charging CHEVROLET DYNASTY 1993 Workshop Manual
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Page 931 of 2438

WIRING DIAGRAMS AA-BODY
INDEX
Wiring Diagram
Name Sheet Number
Airbag System ...............................47
Clockspring ...............................47
Diagnostic Module ..........................47
Interface Grommet ..........................47
Sensor-Left ...............................47
Sensor-Right ..............................47
Squibb ..................................47
Air Conditioning Compressor ...................32, 33
Air Conditioning System (2.5L Engine) ...............71
A/C Cycling Switch ..........................71
Blower Motor ..............................71
Blower Switch .............................71
Control Switch .............................71
Damped Pressure Switch ......................71
Defrost Switch .............................71
Illumination Lamp ...........................71
Resistor .................................71
Air Conditioning System (3.0L Engine) ...............72
A/C Switch ...............................72
Blower Motor ..............................72
Blower Switch .............................72
Control Switch .............................72
Damped Pressure Switch ......................72
Defrost Switch .............................72
High Pressure Switch ........................72
Illumination Lamp ...........................72
Resistor .................................72
Anti-Lock Brake System .................41, 42, 43, 44
ABS Pump Motor Relay .......................41
ABS System Relay ..........................43
ABS Warning Lamp Relay ......................43
Brake Switch ..............................44
Controller ....................... .41, 42, 43, 44
Hydraulic Modulator .........................41
Ignition Switch .............................44
Park Brake Switch ...........................44
Wheel Sensors .............................42
Ash Receiver Lamp ...........................52
Automatic Shut-down Relay .................14, 20, 28
Automatic Transmission Park/Neutral Position and Back-Up Lamp Switch ...............................9
Back-Up Lamp Switch ..........................9
Battery ............................1,5,7,39,40
Blower Motor-A/C ............................71
Blower Motor-Heater ...........................71
Brake Switch ...............................44
Brake Warning Lamp Switch ......................11
Bulkhead Disconnect (50-Way) ................112, 113
Center High Mounted Stop Lamp ..........94, 98, 102, 105
Charging System (2.5L) ........................5,6
Battery ...................................5
Generator .................................6Wiring Diagram
Name Sheet Number
Heated Rear Window Switch .....................5
Charging System (3.0L) ........................7,8
Battery ....................................7
Generator .................................8
Ignition Off-Draw Connector .....................7
Cigar Lighter ................................45
Cigar Lighter Lamp ............................52
Circuit Breaker (30 Amp) Fuseblock Cavity #10 .......67, 82
Circuit Breaker (30 Amp) Fuseblock Cavity #13 . . .2, 66, 67, 86
Clockspring ............................. .47, 59
Cluster Printed Circuit Board .................119, 120
Cluster Printed Circuit Board Connectors .............118
Courtesy Lamps .............................76
Daytime Running Light Module ....................57
Deck Lid Ajar Switch ..........................78
Dimmer Switch-Headlamp .....................1,50
Distributor ......................... .15, 21, 22, 27
EGR Solenoid ...............................24
Electrically Heated Rear Window ...................84
Heated Rear Window .........................84
Switch ..................................84
Timer ...................................84
Electronically Tuned Stereo Radio without Name Brand Speakers ................................87
Electronically Tuned Stereo Radio with Name Brand Speakers ................................89
Speaker Choke .............................89
Speaker Relay .............................89
Electronic Cluster ........................... .121
Engine Coolant Sensor ................... .15, 21, 27
Engine Oil and Temperature Warning System (2.5L) .......39
Engine Oil and Temperature Warning System (3.0L) .......40
Engine Oil Pressure Switch/Sending Unit ...........39, 40
Engine Temperature Sending Unit ................39, 40
Engine Starter System (2.5L Engine & 3.0L ATX) .......9,10
Automatic Transmission Park/Neutral Position Switch .....9
Backup Lamp Switch ..........................9
EMCC Solenoid .............................9
Engine Starter Relay ..........................9
Manual Transmission Back-Up Lamp Switch ...........9
Permanent Magnet Engine Starter Motor .............9
Engine Temperature Sending Unit ................39, 40
Exhaust Gas Recirculation Diagnostic Solenoid ........13, 24
Fan Control System with A/C and Heater System (2.5L) ....32
A/C Compressor ............................32
A/C Compressor Clutch Relay ...................32
A/C High Pressure Switch ......................32
Fan Control Relay ...........................32
Radiator Fan Motor ..........................32
Fan Control System with A/C and Heater System (3.0L) ....33
A/C Conditioning Compressor ...................33
A/C Compressor Clutch Relay ...................33
Ä WIRING DIAGRAMS AA-BODY 8W - 181
Page 1064 of 2438

Wiring Diagram
Name Sheet Number
Relay Bank ............................. .106
Blower Slide Control ...........................51
Bulkhead Disconnect (50 Way) ................181, 182
Bulkhead Disconnect (50-Way) (2.5L Engine) .......183, 184
Bulkhead Disconnect (50-Way) (3.0L Engine) .......185, 186
Bulkhead Disconnect (50-Way) (3.3L & 3.8L Engine) ......................... .187, 188
Camshaft Position Sensor .......................28
Crankshaft Position Sensor .......................28
Cellular Phone System ........................ .126
Antenna ............................... .126
Center Phone ............................ .126
External Speaker .......................... .126
Microphone ............................. .126
Transmitter/Receiver Unit .................... .126
Visor Phone ............................. .126
Charging System (2.5L Engine) ...................5,6
Battery ...................................5
Generator .................................6
Power Distribution Center .......................6
Charging System (3.0L Engine) ...................7,8
Battery ...................................7
Generator .................................8
Power Distribution Center .......................8
Charging System (3.3L & 3.8L Engine) .............9,10
Battery ...................................9
Generator ................................10
Power Distribution Center ......................10
Cigar Lighter .......................... .111, 112
Circuit Breakers Concealed Headlamps .......................2,68
Power Door Locks ........................2,139
Power Seats ............................2,149
Power Windows .........................3,158
Compressor Motor ........................ .40, 42
Concealed Headlamp Controls .....................68
Circuit Breaker .............................68
Headlamp Door Motor ........................68
Headlamp Door Relays ........................68
Headlamp Relay ............................68
Relay Bank ...............................68
Courtesy Lamp System .................87, 88, 89, 90
Left Front Door Courtesy Lamp ..................87
Left Front Door Jamb Switch ....................87
Left Illuminated Visor Vanity Mirror ................89
Left Illuminated Visor Vanity Mirror Switch ...........89
Left Lamp and Switch ........................89
Left Rear Door Courtesy Lamp ...................87
Left Rear Door Jamb Switch ....................87
Left Rear Quarter Reading Lamp ..................90
Right Front Door Courtesy Lamp .................88
Right Front Door Jamb Switch ...................88
Right Illuminated Visor Vanity Mirror ...............89
Right Illuminated Visor Vanity Mirror Switch ..........89
Right Lamp and Switch .......................89
Right Rear Door Courtesy Lamp ..................88
Right Rear Door Jamb Switch ...................88Wiring Diagram
Name Sheet Number
Right Rear Quarter Reading Lamp .................90
Trunk Lamp ...............................90
Data Link Connectors ..........14, 23, 100, 103, 106, 110,
130, 134, 136
Deck Lid Release and Deck Lid Pull-Down System . . . .159, 160
Deck Lid Pull-Down Unit ..................... .160
Deck Lid Release Solenoid .................159, 160
Deck Lid Release Solenoid/Pull-Down Key Cylinder Switch ............................... .160
Mercury Switch .......................... .159
Underhood Light .......................... .159
Dimmer Switch-Optical Horn ....................1,66
Distributor .............................. .17, 19
Door Ajar System w/Electronic Cluster ...............92
Left Front Door Ajar Switch .....................92
Left Rear Door Ajar Switch .....................92
Right Front Door Ajar Switch ....................92
Right Rear Door Ajar Switch ....................92
Door Ajar System w/Mechanical Cluster and Visual Mess Ctr ...............................93
Left Front Door Ajar Switch .....................93
Left Rear Door Ajar Switch .....................93
Right Front Door Ajar Switch ....................93
Right Rear Door Ajar Switch ....................93
Door Ajar System w/Mechanical Cluster w/o Visual Mess Ctr ...............................94
Left Front Door Ajar Switch .....................94
Left Rear Door Ajar Switch .....................94
Right Front Door Ajar Switch ....................94
Right Rear Door Ajar Switch ....................94
Door Electrical Ground Systems ...................165
Door Jamb Courtesy Lamp Switches ..............87, 88
Door Lock System ....................... .139, 140
Circuit Breaker ........................... .139
Connector and Door Lock Switch Function .......139, 140
Door Lock Relay .......................... .140
Door Unlock Relay ......................... .140
Left Front Door Lock Motor ................... .139
Left Front Door Lock Switch ...................139
Left Rear Door Lock Motor ................... .139
Relay Bank ............................. .139
Right Front Door Lock Motor ...................140
Right Front Door Lock Switch ..................140
Right Rear Door Lock Motor ...................140
Exhaust Gas Recirculation Solenoid ............14, 21, 26
Electronically Tuned Stereo Radio ..............119, 120
Left Door Speaker ......................... .120
Left Rear Speaker ......................... .120
Right Door Speaker ........................ .120
Right Rear Speaker ........................ .120
Electronically Tuned Stereo Radio with RS Amplifier ....................... .121, 122, 123
Left Door Speaker ......................... .123
Left Front Speaker ......................... .123
Left Rear Speaker ......................... .123
Right Door Speaker ........................ .123
Right Front Speaker ........................ .123
Right Rear Speaker ........................ .123
8W - 314 WIRING DIAGRAMS AC-AY BODY Ä
Page 1283 of 2438

WIRING DIAGRAMS AG-AJ BODY
ALPHABETICAL INDEX
Wiring Diagram
Name Sheet Number
A/C Compressor Clutch .........................89
A/C and Heater System ..................... .91, 92
A/C Compressor Clutch Relay ...................91
A/C Low Pressure Switch ......................91
A/C High Pressure Switch ......................92
A/C Cycling Switch ..........................92
ABS Warning Lamp Diode .......................69
Airbag System ........................... .84, 85
Clock Spring ..............................84
Diagnostic Module ..........................84
Interface Grommet ..........................85
Left Airbag Sensor ..........................85
Right Airbag Sensor .........................85
Squib (Airbag Igniter) ........................84
Air Conditioning System ........................90
A/C Blower Motor ...........................90
A/C/Heater Blower Motor Resistor .................90
A/C Switch ...............................90
Blower Switch .............................90
Defrost Switch .............................90
Illumination Lamps Switch .....................90
Alarm, Security Module ....................... .127
Ambient Air Temperature Sensor ...............117, 119
Anti-Lock Brake System (Except Turbo 3) .............170
Anti-Lock Brake System Controller ..........68, 69, 70, 71
Anti-Lock Brake System .................68, 69, 70, 71
ABS Controller .................... .68, 69, 70, 71
ABS Hydraulic Modulator ......................68
ABS Pump Motor Relay .......................68
ABS System Relay ..........................69
ABS Warning Lamp Diode ......................69
ABS Warning Switch Lamp Switch ................70
Brake Switch ..............................70
Left Front Wheel Sensor .......................71
Left Rear Wheel Sensor .......................71
Park Brake Switch ...........................70
Right Front Wheel Sensor ......................71
Right Rear Wheel Sensor ......................71
Automatic Shutdown Relay ..................20, 27, 33
Battery ...........................1,9,11,53,56
Body Computer ......................... .165, 166
Body Computer #1 ............................40
Body Computer (Mechanical Cluster) ..............79, 80
Body Computer #2 ............................40
Body Computer (Electronic Cluster) ...............81, 82
Body Wiring to Left Instrument Panel ...............147
Body Wiring to Right Instrument Panel ...........150, 151
Bulkhead Disconnect (50-Way) ................153, 154
Center High Mounted Stop Lamp (AG) ...............140
Center High Mounted Stop Lamp (J-21) ..............141
Center High Mounted Stop Lamp (J-27) ..............142
Charging System (2.5L and Turbo) ................9,10Wiring Diagram
Name Sheet Number
Battery ...................................9
Data Link Connector ..........................9
Generator ................................10
Power Distribution Center ....................9,10
Powertrain Control Module ......................9
Charging System (3.0L) ..................... .11, 12
Battery ..................................11
Generator ................................12
Power Distribution Center .................. .11, 12
Cigar Lighter ................................51
Circuit Breakers (Fuse Cavity #2) ...........8,42,110, 111
Circuit Breakers (Fuse Cavity #3) ..............5,53,116
Clockspring .......................... .59, 65, 84
Clutch Pedal Position Jumper ..................13, 15
Clutch Pedal Position Switch .....................14
Combo Flasher ..............................56
Data Link Connector ..................9,19,25,34,72
Daytime Running Lights Module Connector ............173
Decklid Lock Sense Switch ..................... .102
Dimming Interior Lamps & Headlamp Switch .........51, 52
Ash Receiver Lamp ..........................51
Cluster Lamps .............................52
Cigar Lighter ..............................51
Console Switch Module .......................51
A/C Heater Control Switch Lamp .................52
Headlamp Switch ...........................51
Fog Lamp Switch ...........................51
Fuse Panel Switch ...........................51
Left Pod Lamps ............................51
Left Switch Pod ............................51
Transmission Range Lamp .....................51
Diode ....................................89
Diode Package ....................... .83, 102, 104
Distributor .............................. .21, 26
Dome and Courtesy Lamps (AG) ...............125, 126
Cargo Lamp ............................. .126
Dome Lamp ............................. .126
Front Reading Lamps ....................... .126
Front Reading Lamp Switch ................... .126
Glove Box Lamp & Switch .................... .125
Halo Light .............................. .125
Liftgate Ajar Switch ........................ .125
Vanity Mirror Lamps ....................... .126
Vanity Mirror Lamp Switch ................... .126
Dome, Reading and Courtesy Lamps (J-27 Only) .....121, 122
Courtesy Lamp ........................... .121
Decklid Ajar Switch ........................ .122
Glove Box Lamp .......................... .121
Halo Light .............................. .121
Left Door Courtesy Lamp .................... .122
Rear Mirror Courtesy Lamp ................... .122
Right Door Courtesy Lamp ................... .121
Ä WIRING DIAGRAMS AG-AJ BODY 8W - 533
Page 1467 of 2438

WIRING DIAGRAMS AP BODY D-P
ALPHABETICAL INDEX
Wiring Diagram
Name Sheet Number
ABS Hydraulic Modulator Unit .....................27
ABS Pump Motor Relay .........................27
ABS System Controller ................... .26, 27, 28
ABS System Relay ............................28
ABS Yellow Light Relay .........................28
A/C and Heater System ..................... .47, 48
A/C Cycling Switch ..........................48
A/C High Pressure Switch ......................48
A/C Low Pressure Switch ......................48
Blower Motor ..............................47
Blower Switch .............................47
Defrost Switch .............................47
Illumination Lamp ...........................47
Resistor .................................48
A/C Compressor Clutch Relay .....................50
Airbag Diagnostic Module Connector ................78
Airbag System ...............................35
Clockspring ...............................35
Diagnostic Module ..........................35
Sensors .................................35
Squibb (Airbag Igniter) ........................35
Anti-Lock Braking System ..................26, 27, 28
Data Link Connector .........................27
Hydraulic Modulator Unit ......................27
Pump Motor Relay ..........................27
System Controller ..................... .26, 27, 28
System Relay ..............................28
Wheel Sensors .............................26
Yellow Light Relay ..........................28
Anti-Lock Brake System Controller Connector ...........90
Ash Receiver Lamp ...........................37
Automatic Shut Down Relay 2.2L E.F.I. .............2,14
Automatic Shut Down Relay 2.5L E.F.I. .............2,14
Automatic Shut Down Relay 3.0L .................2,22
Back-Up Lamp Relay ..........................23
Back-Up Lamp Switch .......................7,8,9
Battery .................................1,3,5
Brake Warning Lamp Switch ......................11
Body to Instrument Panel Wiring Left ................87
Cargo Lamp ................................40
Center High Mounted Stop Lamp ................70, 72
Charging System .........................3,4,5,6
Battery .................................3,5
Generator ...............................4,6
Ignition Off Draw Connector ...................3,5
Chime, Key-In, Seat Belt Warning, Headlamp On .........43
Cigar Lighter ................................37
Cigar Lighter Lamp ............................37
Circuit Breakers Headlamp Switch ...........................36
Cavity #8 ..........................2,11,57,58
Cavity #11 ..............................1,60Wiring Diagram
Name Sheet Number
Clockspring .......................... .29, 35, 42
Clutch Pedal Position Jumper ...................8,10
Clutch Pedal Position Switch .....................7,9
Courtesy Lamps .............................72
Data Link Connector ..................... .13, 22, 27
Daytime Running Lamp Jumper ....................30
Daytime Running Lamp Module ....................30
Daytime Running Lights Module Connector ............84
Defrost Switch ..............................47
Dimmer Switch\eadlamp .......................1,36
Dimmer Switch-Optical Horn ....................1,36
Diode 49
Distributor 2.2L, 2.5L ..........................15
Distributor 3.0L ..............................18
Distributor Ignition Coil ..................... .14, 22
Dome Lamp System ....................... .39, 40
Cargo Lamp ..............................40
Dome Lamp ..............................40
Glove Box Lamp ............................39
Glove Box Lamp Switch .......................39
Left Front Door Jamb Switch ....................39
Left Rear Door Jamb Switch ....................40
Liftgate Latch Switch .........................40
Right Front Door Jamb Switch ...................39
Right Rear Door Jamb Switch ...................40
Door and Rear Speakers (Radio) ...................66
Door Jamb Switches ....................... .39, 40
Door Lock System-2 Door .................... .61, 62
Door Lock System-4 Door .................... .63, 64
Engine Coolant Temperature Sending Unit .............12
Engine Coolant Temperature Sensor 2.2L ..............15
Engine Coolant Temperature Sensor 2.5L ..............15
Engine Coolant Temperature Sensor 3.0L ..............18
Engine Oil Pressure Sending Unit/Switch ..............12
Engine Oil Pressure Switch .......................12
Engine Oil Pressure and Temperature System ...........12
Engine to Instrument Panel Wiring ..................86
Engine Starter System ....................7,8,9,10
Engine Starter System (Automatic Transmission) .....2,8,10
Back-Up Lamp Switch .........................8
Clutch Pedal Position Jumper ..................8,10
Engine Starter Motor .......................8,10
Engine Starter Relay ........................8,10
Park/Neutral Position Switch .....................8
Transmission EMCC Solenoid ....................8
Engine Starter System (Manual Transmission) ........2,7,9
Back-Up Lamp Switch .......................7,9
Clutch Pedal Position Switch ...................7,9
Engine Starter Motor ........................7,9
Engine Starter Relay ........................7,9
Squib Igniter (Airbag) ........................35
Exhaust Gas Recirculation Solenoid 2.2L ..............13
Ä WIRING DIAGRAMS AP BODY D-P 8W - 717
Page 1764 of 2438

2.2L/2.5L SINGLE POINT FUEL INJECTIONÐSYSTEM OPERATION INDEX
page page
Air Conditioning (A/C) Clutch RelayÐPCM Output.28
Air Conditioning Switch SenseÐPCM Input ..... 26
Auto Shutdown (ASD) Relay and Fuel Pump RelayÐPCM Output ..................... 29
Battery VoltageÐPCM Input ................ 26
Brake SwitchÐPCM Input .................. 26
EVAP Canister Purge SolenoidÐPCM Output . . . 29
CCD Bus .............................. 25
Coolant Temperature SensorÐPCM Input ...... 26
Data Link ConnectorÐPCM Output ........... 30
Distributor (Hall Effect) Pick-UpÐPCM Input .... 26
Electric Electronic Gas RecirculationÐPCM Output.30
Fuel InjectorÐPCM Output ................. 31
Fuel Pressure Regulator ................... 33
General Information ....................... 24
Generator FieldÐPCM Output ............... 31
Heated Oxygen Sensor (O
2Sensor)ÐPCM Input . 27
Idle Air Control MotorÐPCM Output .......... 29 Ignition CoilÐPCM Output
.................. 31
Malfunction Indicator Lamp (Check Engine)ÐPCM Output ............................... 30
Manifold Absolute Pressure (MAP) SensorÐPCM Input ................................ 27
Modes of Operation ....................... 32
Part Throttle Unlock SolenoidÐPCM Output .... 31
Powertrain Control Module ................. 25
Radiator Fan RelayÐPCM Output ............ 31
Speed Control SolenoidsÐPCM Output ........ 31
Speed ControlÐPCM Input ................. 27
System Diagnosis ........................ 25
TachometerÐPCM Output .................. 32
Throttle Body ............................ 33
Throttle Position Sensor (TPS)ÐPCM Input ..... 28
Transaxle Park/Neutral SwitchÐPCM Input ..... 28
Vehicle Speed SensorÐPCM Input ........... 28
GENERAL INFORMATION
The computer regulated, Electronic Fuel Injection
System (Fig. 1) provides a precise air/fuel ratio for
all driving conditions. The fuel injection system is
controlled by the powertrain control module (PCM).
The PCM is a pre-programmed digital computer. The
PCM regulates ignition timing, air-fuel ratio, emission
control devices, cooling fan, charging system, speed con-
trol, and idle speed. The PCM can adapt its requirement
to meet changing operating conditions.
Fig. 1 Electronic Fuel Injection Components
14 - 24 FUEL SYSTEMS Ä
Page 1770 of 2438

The PCM removes the ground to the solenoid when
the engine reaches a specified temperature and the
time delay interval has occurred. When the solenoid is
de-energized, vacuum flows to the canister purge
valve. Vapors are purged from the canister and flow to
the throttle body. The purge solenoid is also energized during certain
idle conditions to update the fuel delivery calibration.
MALFUNCTION INDICATOR LAMP (CHECK
ENGINE)ÐPCM OUTPUT
The Malfunction Indicator lamp (instrument panel
Check Engine lamp) comes on each time the ignition
key is turned ON and stays on for 3 seconds as a bulb
test. The malfunction indicator lamp warns the opera-
tor that the PCM has entered a Limp-in mode. During
Limp-in-Mode, the PCM attempts to keep the system
operational. The malfunction indicator lamp signals
the need for immediate service. In limp-in mode, the
PCM compensates for the failure of certain components
that send incorrect signals. The PCM substitutes for
the incorrect signals with inputs from other sensors. Signals that can trigger the Malfunction Indi-
cator Lamp.
² Coolant Temperature Sensor
² Manifold Absolute Pressure Sensor
² Throttle Position Sensor
² Battery Voltage Input
² An Emissions Related System
² Charging system
The malfunction indicator lamp can also be used to
display diagnostic trouble codes. Cycle the ignition
switch on, off, on, off, on, within five seconds and any
diagnostic trouble codes stored in the PCM will be
displayed. Refer to the 2.2L/2.5L Single Point Fuel
InjectionÐOn-Board Diagnostics section in this group.
DATA LINK CONNECTORÐPCM OUTPUT
The data link connector provides the technician with
the means to connect the DRBII scan tool to diagnosis
the vehicle.
ELECTRIC ELECTRONIC GAS
RECIRCULATIONÐPCM OUTPUT
The electronic exhaust gas recirculation transducer
(EET) is a back pressure transducer/electric vacuum
solenoid assembly (Fig. 13). The EET assembly mounts
above the EGR valve (Fig. 14).
The solenoid turns the vacuum supply to the trans-
ducer on and off. The electric vacuum solenoid portion
of the EET energizes when the PCM provides a ground
path. When the solenoid energizes, vacuum is pre-
vented from flowing to the transducer. When the sole-
noid de-energizes, vacuum flows to the transducer. The
solenoid energizes during engine warm-up, closed
throttle (idle or cruise), wide open throttle, and rapid
acceleration/deceleration. If the solenoid wire con-
nector is disconnected, the EGR valve will oper-
ate at all times.
Fig. 12 EVAP Canister Purge Solenoid
Fig. 13 Electronic EGR Recirculation Transducer
Fig. 14 EGR Valve and Electric EGR Transducer
14 - 30 FUEL SYSTEMS Ä
Page 1771 of 2438

FUEL INJECTORÐPCM OUTPUT
The Fuel Injector is an electric solenoid operated
by the PCM (Fig. 15).
Based on sensor inputs, the PCM determines when
and how long the fuel injector should operate. The
amount of time the injector fires is referred to as in-
jector pulse width. The auto shutdown (ASD) relay
supplies battery voltage to the injector. The PCM
supplies the ground path. By switching the ground
path on and off, the PCM adjusts injector pulse
width. When the PCM supplies a ground path, a
spring loaded needle or armature lifts from its seat.
Fuel flows through the orifice and deflects off the
sharp edge of the injector nozzle. The resulting fuel
sprays forms a 45É cone shaped pattern before enter-
ing the air stream in the throttle body. Fuel is supplied to the injector constantly at regu-
lated 270 Kpa (39 psi). Unused fuel returns to the
fuel tank.
GENERATOR FIELDÐPCM OUTPUT
The PCM regulates the charging system voltage
within a range of 12.9 to 15.0 volts. Refer to Group
8A for charging system information.
IGNITION COILÐPCM OUTPUT
The PCM provides a ground contact (circuit) for en-
ergizing the ignition coil. When the PCM breaks the
contact, the energy in the coil primary transfers to
the secondary causing the spark. The PCM will de-
energize the ASD relay if it does not receive an input
from the distributor pick-up. Refer to Auto Shutdown
(ASD) Relay/Fuel Pump RelayÐPCM Output in this
section for relay operation. The ignition coil is mounted on the hot box next to
the thermostat housing (Fig. 16).
PART THROTTLE UNLOCK SOLENOIDÐPCM
OUTPUT
Three-speed automatic transaxles use a part throt-
tle unlock solenoid. The PCM controls the lock-up of
the torque convertor through the part throttle unlock
solenoid. The transaxle is locked up only in direct
drive mode. Refer to Group 21 for transaxle informa-
tion.
RADIATOR FAN RELAYÐPCM OUTPUT
The radiator fan is energized by the PCM through
the radiator fan relay. The PCM grounds the radia-
tor fan relay when engine coolant reaches a predeter-
mined temperature. For more information, refer to
Group 7, Cooling Systems. On AC, AG and AJ models, the radiator fan relay
is located in the power distribution center. Refer to
the Wiring and Component Identification section of
Group 8W. On AA and AP models, the radiator fan relay is
mounted on the drivers side fender well, next to the
strut tower (Fig. 10).
SPEED CONTROL SOLENOIDSÐPCM OUTPUT
The speed control vacuum and vent solenoids are
operated by the PCM. When the PCM supplies a
ground to the vacuum and vent solenoids, the speed
control system opens the throttle blade. When the
PCM supplies a ground only to the vent solenoid, the
throttle blade holds position. When the PCM removes
the ground from both the vacuum and vent solenoids,
the throttle blade closes. The PCM balances the two
solenoids to maintain the set speed. Refer to Group
8H for speed control information.
Fig. 15 Fuel Injector
Fig. 16 Ignition Coil
Ä FUEL SYSTEMS 14 - 31
Page 1785 of 2438

SYSTEMS TEST
WARNING: APPLY PARKING BRAKE AND/OR
BLOCK WHEELS BEFORE PERFORMING A TEST
WITH THE ENGINE OPERATING.
OBTAINING DIAGNOSTIC TROUBLE CODES
(1) Connect DRBII scan tool to the data link con-
nector located in the engine compartment near the
powertrain control module (PCM). (2) Start the engine if possible, cycle the transaxle
selector and the A/Cswitch if applicable. Shut off
the engine. (3) Turn the ignition switch on, access Read Fault
Screen. Record all the fault messages shown on the
DRBII scan tool. Observe the malfunction indicator
lamp (check engine lamp on the instrument panel).
The lamp should light for 3 seconds then go out (bulb
check).
STATE DISPLAY TEST MODE
The switch inputs used by the powertrain control
module (PCM) have only two recognized states,
HIGH and LOW. For this reason, the PCM cannot
recognize the difference between a selected switch po-
sition versus an open circuit, a short circuit, or a de-
fective switch. If the change is displayed, it can be
assumed that the entire switch circuit to the PCM is
functional. From the state display screen access ei-
ther State Display Inputs and Outputs or State Dis-
play Sensors.
STATE DISPLAY INPUTS AND OUTPUTS
Connect the DRBII scan tool to the vehicle and ac-
cess the State Display screen. Then access Inputs and
Outputs. The following is a list of the engine control
system functions accessible through the Inputs and
Outputs screen. Park/Neutral Switch (automatic transaxle only)
Speed Control Resume
Brake Switch
Speed Control On/Off
Speed Control Set
A/C Switch Sense
S/C (Speed Control) Vent Solenoid
S/C (Speed Control) Vacuum Solenoid
Torque Converter Clutch Solenoid (3 speed auto-
matic transaxle)
A/C Clutch Relay
EGR Solenoid
Auto Shutdown Relay
Radiator Fan Relay
Purge Solenoid
Malfunction Indicator (Check Engine) Lamp
STATE DISPLAY SENSORS
Connect the DRBII scan tool to the vehicle and ac-
cess the State Display screen. Then access Sensor
Display. The following is a list of the engine control
system functions accessible through the Sensor Dis-
play screen. Oxygen Sensor Signal
Coolant Temperature
Coolant Temp Sensor
Throttle Position
Minimum Throttle
Battery Voltage
MAP Sensor Reading
Idle Air Control Motor Position
Added Adaptive Fuel
Adaptive Fuel Factor
Barometric Pressure
Min Airflow Idl Spd
Engine Speed
Fault #1 Key-On Info
Module Spark Advance
Speed Control Target
Fault #2 Key-On Info
Fault #3 Key-On Info
Speed Control Status
Charging System Goal
Theft Alarm Status
Speed Control Switch Voltage
Map Sensor Voltage
Vehicle Speed
Oxygen Sensor State
MAP Gauge Reading
Throttle Opening (percentage)
Total Spark Advance
CIRCUIT ACTUATION TEST MODE
The circuit actuation test mode checks for proper
operation of output circuits or devices which the pow-
ertrain control module (PCM) cannot internally rec-
ognize. The PCM can attempt to activate these
outputs and allow an observer to verify proper oper-
ation. Most of the tests provide an audible or visual
indication of device operation (click of relay contacts,
spray fuel, etc.). With the exception of an intermit-
tent condition, if a device functions properly during
its test, it can be assumed that the device, its associ-
ated wiring, and its driver circuit are in working or-
der.
OBTAINING CIRCUIT ACTUATION TEST
Connect the DRBII scan tool to the vehicle and ac-
cess the Actuators screen. The following is a list of
the engine control system functions accessible
through Actuators screens. Stop All Tests
Ignition Coil #1
Fuel Injector #1
Idle Air Control Motor Open/Close
Ä FUEL SYSTEMS 14 - 45
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² Methanol Concentration Sensor
² Pressure relief/Rollover valve
² PCV Valve
² All fuel system and emission system hoses and
tubes
SYSTEM OPERATION
The flexible fuel vehicle's 2.5L engine use a se-
quential multi-port electronic fuel injection system
(Fig. 1). The powertrain control module (PCM) oper-
ates the electronic fuel injection system. The PCM
provides precise air/fuel ratios and ignition timing
for all driving conditions.
The PCM regulates the air-fuel ratio, ignition coil
dwell and idle speed. The PCM also operates the
high speed and low speed cooling fans, charging sys-
tem, speed control system and various emission con-
trol devices. Various sensors and switches provide inputs to the
PCM. The PCM converts all inputs into signals and
regulates various systems based on the inputs. The
PCM adjusts the systems it controls to meet chang-
ing operating conditions. Fuel is injected into the intake port above the in-
take valve in precise metered amounts through elec-
trically operated injectors. The PCM operates the
injectors in a specific sequence. The PCM adjusts the
air/fuel ratio based on the percentage of methanol in the fuel. The PCM constantly adjusts injector pulse
width to obtain the ideal air fuel ratio for the current
percentage of methanol in the fuel. Injector pulse
width refers to the amount of time an injector oper-
ates. The PCM adjusts injector pulse width by opening
and closing the ground path to the injectors. Engine
RPM (speed), manifold absolute pressure (air density)
and the percentage of methanol in the fuel are the
primary inputs that determine injector pulse width.
SYSTEM DIAGNOSIS
The powertrain control module (PCM) can test
many of its own input and output circuits. If the
PCM senses a fault in a major system, the PCM
stores a diagnostic trouble code in memory. Technicians can display stored diagnostic trouble
codes by two different methods. The first is to cycle
the ignition switch On - Off - On - Off - On within 5
seconds. Then count the number of times the mal-
function indicator lamp (check engine lamp) on the
instrument panel flashes on and off. The number of
flashes represents the trouble code. There is a slight
pause between the flashes representing the first and
second digits of the code. Longer pauses separate in-
dividual trouble codes.
Fig. 1 Flexible Fuel MPI Components
14 - 56 FUEL SYSTEMS Ä
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ter mounting studs (Fig. 12). The top of the solenoid
has the word TOP on it. The solenoid will not oper-
ate unless it is installed correctly.
DATA LINK CONNECTORÐPCM OUTPUT
The data link connector provides the technician
with the means to connect the DRBII scan tool to di-
agnosis the vehicle.
FUEL INJECTORÐPCM OUTPUT
The Fuel Injectors are electric solenoids driven by
the PCM (Fig. 13). Based on sensor inputs, the PCM
determines when and how long the fuel injector
should operate. The amount of time an injector fires
is referred to as injector pulse width. The auto shut-
down (ASD) relay supplies battery voltage to the in-
jector. The PCM supplies the ground path. By
switching the ground path on and off, the PCM ad-
justs injector pulse width.
When the PCM supplies a ground path, a spring
loaded needle or armature lifts from its seat and fuel
flows through the injector orifice. Fuel is constantly supplied to the injector at regu-
lated 380 Kpa (55 psi). Unused fuel returns to the
fuel tank.
GENERATOR FIELDÐPCM OUTPUT
The PCM regulates the charging system voltage
within a range of 12.9 to 15.0 volts. Refer to Group
8A for charging system information.
IDLE AIR CONTROL MOTORÐPCM OUTPUT
The idle speed stepper motor is mounted on the
throttle body and is controlled by the PCM (Fig. 9).
The PCM adjusts engine idle speed through the idle
air control motor to compensate for engine load or
ambient conditions. The throttle body has an air bypass passage that
provides air for the engine at idle (the throttle blade is closed). The idle air control motor pintle protrudes
into the air bypass passage and regulates air flow
through it. The PCM adjusts engine idle speed by moving the
idle air control motor pintle in and out of the bypass
passage. The adjustments are based on inputs the
PCM receives from the throttle position sensor, speed
sensor (distributor pick-up coil), coolant temperature
sensor, and various switch operations (brake, park/
neutral, air conditioning). Deceleration die out is also
prevented by increasing airflow when the throttle is
closed quickly.
IGNITION COILÐPCM OUTPUT
The PCM provides a ground contact (circuit) for en-
ergizing the ignition coil. When the PCM breaks the
contact, the energy in the coil primary transfers to
the secondary causing the spark. The PCM will de-
energize the ASD relay if it does not receive an input
from the distributor pick-up. Refer to Auto Shutdown
(ASD) Relay/Fuel Pump RelayÐPCM Output in this
section for relay operation. The ignition coil is mounted on the hot box next to
the thermostat housing (Fig. 14).
MALFUNCTION INDICATOR (CHECK ENGINE)
LAMPÐPCM OUTPUT
The malfunction indicator lamp (instrument panel
Check Engine lamp) comes on each time the ignition
key is turned ON and stays on for 3 seconds as a
bulb test. The malfunction indicator lamp warns the
operator that the PCM has entered a Limp-in mode.
During Limp-in-Mode, the PCM attempts to keep the
system operational. The malfunction indicator lamp
signals the need for immediate service. In limp-in
Fig. 13 Fuel Injector
Fig. 14 Ignition Coil
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