high beam CHEVROLET DYNASTY 1993 User Guide
[x] Cancel search | Manufacturer: CHEVROLET, Model Year: 1993, Model line: DYNASTY, Model: CHEVROLET DYNASTY 1993Pages: 2438, PDF Size: 74.98 MB
Page 1066 of 2438
Wiring Diagram
Name Sheet Number
Left Cornering Lamp .........................82
Left High Beam Headlamp ......................82
Left Low Beam Headlamp ......................82
Left Park/Turn Signal Lamp .....................82
Left Side Marker Lamp ........................82
Right Cornering Lamp ........................81
Right High Beam Headlamp .....................81
Right Low Beam Headlamp .....................81
Right Park/Turn Signal Lamp ....................81
Right Side Marker Lamp .......................81
Front End Lighting Concealed Headlamps with D.R.L. (New Yorker/5th Avenue) ................... .83, 84
Daytime Running Lamp Module ..................84
Left Cornering Lamp .........................84
Left High Beam Headlamp ......................84
Left Low Beam Headlamp ......................84
Left Park/Turn Signal Lamp .....................84
Left Side Marker Lamp ........................84
Right Cornering Lamp ........................83
Right High Beam Headlamp .....................83
Right Low Beam Headlamp .....................83
Right Park/Turn Signal Lamp ....................83
Right Side Marker Lamp .......................83
Fuel Injection Ignition System (3.0L) ......19, 20, 21, 22, 23
Automatic Shut Down Relay ....................23
Data Link Connector .........................23
Distributor ...............................19
Distributor Ignition Coil .......................23
Engine Coolant Temperature Sensor ...............19
EVAP/Purge Solenoid .........................20
Exhaust Gas Recirculation Solenoid ................21
Heated Oxygen Sensor ........................19
Idle Air Control Motor ........................21
Injectors .................................20
MAP Sensor ..............................21
Power Steering Switch ........................19
Powertrain Control Module ...........19, 20, 21, 22, 23
Throttle Position (Sensor) ......................21
Fuel Injection Ignition System (3.3L & 3.8L) .............. .24, 25, 26, 27, 28, 29
Automatic Shut Down Relay ....................29
Camshaft Position Sensor ......................28
Crankshaft Position Sensor .....................28
Data Link Connector .........................29
Direct Ignition System Coil Pack ..................24
Engine Coolant Temperature Sensor ...............25
EVAP/Purge Solenoid .........................27
Exhaust Gas Recirculation Solenoid ................26
Heated Oxygen Sensor ........................25
Idle Air Control Motor ........................26
Injectors .................................24
MAP Sensor ..............................26
Power Steering Switch ........................25
Powertrain Control Module .........24, 25, 26, 27, 28, 29
Throttle Position (Sensor) ......................26
Fuel Pump Motor .............................36
Fuel Pump Relay .............................36Wiring Diagram
Name Sheet Number
Fuel Tank Level Gauge Sending Unit .................36
Fuse Application Chart .....................1,2,3,4
Fuseblock Module ........................... .168
Fuses Fuse #1 ...............................2,66
Fuse #2 ........................2,37,43,59,66
Fuse #3 .............1,66,69,71,73,75,78,81,83,
96, 102, 105, 110
Fuse #4 .............1,66,69,71,73,75,78,81,83,
96, 102, 105, 110
Fuse #5 ................1,51,53,55,65,85,95,99,
101, 116, 119, 121, 128, 132, 136, 148
Fuse #6 .....................4,11,15,22,27,37
Fuse #7 ..................4,11,15,22,27,41,147
Fuse #8 . . .4, 11, 15, 22, 27, 57, 67, 95, 100, 102, 104, 107, 109, 128, 132, 135, 141
Fuse #9 ............3,11,57, 115, 124, 125, 148, 158
Fuse #10 ....................3,11,51,53,55,115
Fuse #11 .......................3,11,12,33,53
Fuse #12 ...................... .88, 91, 112, 159
Fuse #13 ...........................4,99,159
Fuse #14 ...............................1,64
Fuse #15 ...........2,6,7,9,57,64, 118, 126, 128, 1
32, 136, 139, 151, 160
Fuse #16 ..............................2,122
Fuse #17 .......................4, 143, 146, 148
Fuse #18 ........3,11,62, 103, 106, 108, 130, 134, 137
Fuse #19 ............................3,11,59
Fuse #20 .....................3,11, 119, 121, 126
Fuse F1-Power Distribution Center .........4,5,7,9,148
Fuse F2-Hazard Lamp ......................5,7,9
Generator ..............................6,8,10
Glove Box Module and Front Cigar Lighter ............111
Ash Receiver Lamp ........................ .111
Deck Lid Release Switch ..................... .111
Front Cigar Lighter ........................ .111
Glove Box Lamp and Switch ...................111
Hazard Flasher ..............................59
Headlamp Dimmer Switch .....................1,66
Headlamp Switch .........................1,65,66
Optical Horn/Headlamp Dimmer Switch .............66
Headlamps-Aero ..................... .69, 70, 71, 72
Headlamps-Concealed . . .73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84
Headlamp Switch Controlled Interior Lighting ...........85
Headlamp Switch Lamp .......................85
Transmission Range Lamp with Electronic Cluster .......85
Heated Oxygen Sensor ................... .14, 19, 25
Heated Rear Window ......................... .148
Heated Rear Window Switch ...................148
Rear Window Grid ......................... .148
Heated Rear Window Switch ...................4,148
Heater Bi-Lever Control Switch ....................51
Heater Blower Motor ...........................51
Heater Blower Motor Resistor .....................51
Heater System ...............................51
Bi-level Control Switch ........................51
Blower Motor ..............................51
8W - 316 WIRING DIAGRAMS AC-AY BODY Ä
Page 1285 of 2438
Wiring Diagram
Name Sheet Number
Engine Starter Relay .........................15
Park/Neutral Safety Switch .....................15
Transmission Range Switch .....................15
Engine Temperature Sending Unit ................40, 41
Enthusiast Seat Jumper ....................... .114
Lumbar Pump ........................... .114
Lumbar Switch ........................... .114
Power Seat Motors ........................ .114
Recliner Seat Back ......................... .114
Wing Motor ............................. .114
Wing Switch ............................ .114
Exhaust Gas Recirculation Diagnostic Solenoid ........18, 24
EVAP/Purge Solenoid .................... .18, 29, 30
Fan Control System ...........................89
A/C Compressor Clutch .......................89
Diode ...................................89
Fan Control Relay ...........................89
Radiator Fan Motor ..........................89
Field Coil Engine Starter Motor ...............13, 14, 15
Front Door & Rear Speakers (w/NBS) ................62
Front End Lighting (Canada) (G Body Only) ..........47, 48
Left Fog Lamp .............................47
Left Headlamp High Beam ......................47
Left Headlamp Low Beam ......................47
Left Park & Turn Signal Lamp ...................47
Right Fog Lamp ............................48
Right Headlamp High Beam .....................48
Right Headlamp Low Beam .....................48
Right Park & Turn Signal Lamp ..................48
Front End Lighting (Canada) (J Body Only) ..........49, 50
Dummy Lamp .......................... .49, 50
Front Left Side Marker Lamp ....................49
Front Right Side Marker Lamp ...................50
Left Headlamp (Inboard) (High Beam) ..............49
Left Headlamp (Outboard) (Low Beam) .............49
Left Park & Turn Signal Lamp ...................49
Right Headlamp (Inboard) (High Beam) .............50
Right Headlamp (Outboard) (Low Beam) ............50
Right Park & Turn Signal Lamp ..................50
Front End Lighting (G Body Only) ................43, 44
Left Fog Lamp .............................43
Left Headlamp High Beam ......................43
Left Headlamp Low Beam ......................43
Left Park & Turn Signal Lamp ...................43
Right Fog Lamp ............................44
Right Headlamp High Beam .....................44
Right Headlamp Low Beam .....................44
Right Park & Turn Signal Lamp ..................44
Front End Lighting (J Body Only) ................45, 46
Dummy Lamp .......................... .45, 46
Front Left Side Marker Lamp ....................45
Front Right Side Marker Lamp ...................46
Left Headlamp (Inboard) (High Beam) ..............45
Left Headlamp (Outboard) (Low Beam) .............45
Left Park & Turn Signal Lamp ...................45
Right Headlamp (Inboard) (High Beam) .............46
Right Headlamp (Outboard) (Low Beam) ............46Wiring Diagram
Name Sheet Number
Right Park & Turn Signal Lamp ..................46
Front Reading Lamps ..................... .124, 126
Fuel Injection Ignition System (3.0L) .........23, 24, 25, 26,
27, 28, 29
Automatic Shut Down Relay ....................27
Data Link Connector .........................25
Distributor ...............................26
EGR Diagnostic Solenoid ......................24
Engine Coolant Temperature Sensor ...............26
EVAP/Purge Solenoid .........................29
Heated Oxygen Sensor ........................24
Idle Air Control Motor ........................23
Ignition Coil ...............................23
Injectors .................................28
MAP Sensor ..............................29
Powertrain Control Module .........23, 24, 25, 26, 27, 29
Throttle Position (Sensor) ......................27
Vehicle Speed Sensor ........................25
Fuel Injection Ignition System (2.5L) . . . .17, 18, 19, 20, 21, 22
Automatic Shut Down Relay ....................20
Data Link Connector .........................19
Distributor ...............................21
EVAP/Purge solenoid .........................18
Engine Coolant Temperature Sensor ...............21
Exhaust Gas Recirculation Diagnostic Solenoid .........18
Heated Oxygen Sensor ........................17
Idle Air Controller Motor .......................17
Ignition Coil ...............................19
Injector .................................22
MAP Sensor ..............................18
Powertrain Control Module .........17, 18, 19, 20, 21, 22
Throttle Position (Sensor) ......................17
Vehicle Speed Sensor ........................21
Fuel Injection Ignition System (Turbo III) ........30, 31, 32,
33, 34, 35,
Automatic Shut Down Relay ....................33
Barometer Solenoid ..........................30
Camshaft Position Sensor ......................30
Charge Air Temperature Sensor ..................32
Crankshaft Position Sensor .....................33
Data Link Connector .........................34
Engine Coolant Temperature Sensor ...............32
EVAP/Purge Solenoid .........................30
Fuel Injectors ..............................31
Heated Oxygen Sensor ........................32
Idle Air Control Motor ........................34
Injector .................................31
Knock Sensor .............................33
MAP Sensor ..............................30
Powertrain Control Module .........30, 31, 32, 33, 34, 35
Throttle Position (Sensor) ......................34
Vehicle Speed Senor .........................35
Waste Gate Solenoid .........................30
Fuel Tank Gauge Level Sending Unit ................107
Fuel Gauge ............................. .107
Fuel Pump .............................. .107
Fuel Tank System ........................ .107, 108
Ä WIRING DIAGRAMS AG-AJ BODY 8W - 535
Page 1286 of 2438
Wiring Diagram
Name Sheet Number
Fuel Gauge ............................. .107
Fuel Pump Module ........................ .107
Fuel Pump Relay .......................... .108
Fuel Tank Gauge Level Sending System ............107
Fuse Application Chart (Engine Compartment) ......1,2,3,4
Fuse Application Chart (Instrument Panel) .........5,6,7,8
Fuse Block ............................... .143
Fuses Fuse 1 ...........................8,42,90,93
Fuse 5 ....................8,13,14,39,42,84,96
Fuse 6 ..............................8,42,56
Fuse 7 .............................8,42,105
Fuse 8 ................................5,52
Fuse 9 ................................5,55
Fuse 10 ..........................5,10,12,54
Fuse 11 ..........................5,60,84,88
Fuse 12 ...............................5,63
Fuse 14 .....................7,42,70,73,77,84
Fuse 15 ..........................7,42,59,70
Fuse 17 .........................6,53, 133, 137
Fuse 18 .........................6,53, 133, 137
Fuse 19 ...............................6,54
Fuse 20 ...............................6,54
Fuse 21 ..........................5,10,12,59
Fuse 22 ...............................5,65
Fuse 25 .......................8,94,95,98,100
Fuse 26 ..............8,16,73,77,94, 121, 123, 125
Fuse 27 ..........................7,42,61,63
Fuse 28 .............................7,42,67
Fuse 36 ...........................1,9,11,56
Fuse 37 ..................................1
Fuse 40 ..............................2,9,11
Fuse 41 ..............................2,9,11
Fuse 42 ...........................2,9,11,18
Fuse 43 ..................................2
Fuse 44 .............................2,10,12
Fuse 45 .............................2,10,12
Fuse 46 ..............................2,9,11
Fuse 47 ..............................2,9,11
Fuse 48 .............................1,10,12
Fuse 50 .............................1,10,12
Fuse 51 .............................2,10,12
Fuse 52 .............................4,10,12
Fuse 53 .............................4,10,12
Fuse 55 ..........................2,10,12,13
Fuse 56 ........................3,10,12,54,84
Fuse 57 ..........................3,10,12,54
Fuse 58 .............................1,10,12
Generator .............................. .10, 12
Glove Box Lamp Switch ................... .101, 103
Headlamp Switch ......................... .51, 55
Headlamp Switch System .................. .53, 54, 55
Battery ..................................53
Fog Lamp Relay ............................55
Fog Lamp Switch ...........................55
Headlamp Switch ...........................55
High Beam Relay ...........................53Wiring Diagram
Name Sheet Number
Left Pod Light .............................55
Low Beam Relay ............................53
Optical Horn Switch .........................55
Park Lamp Relay ...........................53
Parking Switch .............................55
Turn Signal Switch ..........................55
Heated Oxygen Sensor ................... .17, 24, 32
Heated Rear Window ......................8,94,95
Heated Rear Window Switch .................8,94,95
Heater System ...............................93
Blower Motor ..............................93
Blower Motor Resistor ........................93
Blower Switch .............................93
Illumination Lamp Switch ......................93
High Beam Relay ...........................6,53
Horn System ...............................65
Clockspring ...............................65
Horn Relay ...............................65
Horn Switch ..............................65
Left Horn (Lo-Note) ..........................65
Right Horn (Hi-Note) .........................65
Idle Air Control Motor ...................... .17, 23
Ignition Coil ............................. .19, 23
Ignition Switch ...........................2,7,42
Instrument Panel Fuse Application Chart ..........5,6,7,8
Intermittent Wiper System .................... .66, 67
Intermittent Windshield Wiper Motor ...............67
Park Switch ...............................67
Washer Relay .............................66
Windshield Washer Low Fluid Level Sensor ...........67
Windshield Washer Pump Motor .................67
Wiper Switch ..............................66
Interface Grommet ............................85
Key Disarm Switch ....................... .115, 116
Lamp Outage Module Connectors ..................174
Lamps A/C Heater Control Lamp ......................52
Ash Receiver Lamp ..........................51
Back-Up Lamps ...........128, 131, 133, 134, 137, 138
Cargo Lamp ............................. .126
Center High Mounted Stop Lamp ..........140, 141, 142
Cluster Lamps .............................52
Console Switch Module Lamp ...................51
Courtesy Lamps ................ .121, 122, 123, 124
Dome Lamp ......................... .118, 126
Dummy Lamp .......................... .45, 46
Fog Lamp-Left ......................... .43, 47
Fog Lamp-Right ........................ .44, 48
Glove Box Lamp ............. .101, 103, 121, 123, 125
Halo Light ....................... .121, 123, 125
Headlamp, High Beam .......43, 44, 45, 46, 47, 48, 49, 50
Headlamp, Low Beam .......43, 44, 45, 46, 47, 48, 49, 50
Illumination Lamp ....................... .90, 93
Left Pod Lamps ......................... .51, 55
License Lamp .................. .128, 131, 133, 137
Park and Turn Signal Lamp-Left ........43, 45, 47, 49, 50
Park and Turn Signal Lamp-Right .......44, 46, 48, 49, 50
8W - 536 WIRING DIAGRAMS AG-AJ BODY Ä
Page 1288 of 2438
Wiring Diagram
Name Sheet Number
Right Tail Lamp .......................... .131
Right Tail, Stop & Signal Lamps .................131
Rear Lighting w/Lamp Outage (AJ) .......136, 137, 138, 139
Lamp Outage Module ....................... .138
Left Back-Up Lamp ........................ .137
Left Side Marker Lamp ...................... .136
Left Tail Lamp ........................... .136
Left Tail/Stop Lamps ....................... .136
License Lamps ........................... .137
Right Back-Up Lamp ....................... .138
Right Side Marker Lamp ..................... .139
Right Tail Lamp .......................... .138
Right Tail/Stop ........................... .139
Turn Lamp .......................... .136, 139
Rear Lighting without Lamp Outage ......132, 133, 134, 135
Left Back-up Lamp ........................ .133
Left Side Marker Lamp ...................... .132
Left Tail/Stop Lamp ........................ .132
Left Tail Lamp ........................... .132
License Lamp ............................ .133
Right Back-Up Lamp ....................... .134
Right Side Marker Lamp ..................... .135
Right Tail Lamp .......................... .134
Right Tail/Stop Lamp ....................... .135
Turn Lamp .......................... .132, 135
Relay Block ..................... .60, 162, 163, 164
Relays ABS Pump Motor Relay .......................68
ABS System Relay ..........................69
A/C Compressor Clutch Relay ...................91
ADL Relay .............................. .115
Automatic Shut Down Relay ...............20, 27, 33
Backup Lamp Relay ..........................38
Diode Package Relay ..................... .56, 83
Engine Starter Relay ................... .13, 14, 15
Fan Control Relay ...........................89
Fog Lamp Relay ............................55
Fuel Pump Relay .......................... .108
High Beam Relay ..........................6,53
Horn Relay ...............................65
Left Front Turn Signal Relay ....................57
Left Rear Turn Signal Relay .....................57
Low Beam Relay ..........................6,53
Name Brand Speaker Relay .....................60
Park Lamp Relay ..........................5,53
Power Top Relay ...........................96
Right Front Turn Signal Relay ...................57
Right Rear Turn Signal Relay ....................57
Safety Shut Down Relay .......................36
Washer Relay .............................66
Resistors .............................. .90, 93
A/C and Heater Blower Motor Resistor ..............90
Heater Blower Motor Resistor ...................93
Right Instrument Panel to Body Wiring ...........148, 149
RS Amplifier ............................ .63, 64
RS Amplifier Connectors ...................... .159
Security Alarm Module .................... .127, 172Wiring Diagram
Name Sheet Number
Security Alarm System ....................... .127
Sending Unit, Fuel Tank ....................... .107
Sensors Airbag Sensor .............................85
Ambient Air Temperature Sensor .............117, 119
Brake Fluid Level Sensor ......................72
Camshaft Position Sensor ......................30
Charge Air Temperature Sensor ..................32
Crankshaft Position Sensor .....................33
Coolant Level Sensor .........................72
Engine Coolant Temperature Sensor ..........21, 26, 32
Engine Oil Level Sensor .......................41
Heated Oxygen Sensor .................. .17, 24, 32
Knock Sensor .............................33
Left Front Wheel Sensor .......................71
Left Rear Wheel Sensor .......................71
MAP Sensor ........................ .18, 29, 30
Output Speed Sensor .........................39
Right Front Wheel Sensor ......................71
Right Rear Wheel Sensor ......................71
Throttle Position (Sensor) .................17, 27, 34
Turbine Speed Sensor ........................39
Vehicle Speed Sensor .................. .21, 25, 35
Windshield Washer Low Fluid Level Sensor ...........67
Solenoids Barometer ................................30
EMCC Solenoid ............................13
EVAP/Purge Solenoid ................... .18, 29, 30
Exhaust Gas Recirculation Diagnostic Solenoid ......18, 24
Transmission Solenoid ........................36
Waste Gate Solenoid .........................30
Speakers .......................... .61, 62, 63, 64
Splices Splice A3 .......................... .10, 12, 53
Splice A11 ............................ .10, 12
Splice A21-1 ...................... .11, 20, 25, 33
Splice A21-2 ..............................38
Splice A142 ........................9,27,28,32
Splice A142-1 .................. .10, 12, 19, 23, 32
Splice A142-2 .............................28
Splice A142-3 .......................... .28, 31
Splice B47 ...............................69
Splice C7 ............................. .90, 93
Splice C15 ...........................8,94,95
Splice D1 ...................... .77, 86, 117, 119
Splice D1-1 ........................... .29, 86
Splice D2 ...................... .77, 87, 117, 119
Splice D2-1 ........................... .29, 87
Splice E2 .......................... .51, 52, 87
Splice E17 ...............................51
Splice F12-1 ...................9,11,18,19,25,32
Splice F12-2 ...................... .11, 18, 29, 30
Splice F13 ................................67
Splice F20 .........................8,84,92,96
Splice F21-2 ......................... .110, 111
Splice F30 ...................... .60, 84, 88, 127
Splice F35-1 ......................... .113, 115
8W - 538 WIRING DIAGRAMS AG-AJ BODY Ä
Page 1632 of 2438
3.0L ENGINE INDEX
page page
Accessory Drive Belt Service ................ 70
Auto Lash Adjuster ....................... 75
Camshaft Service ........................ 76
Checking Engine Oil Pressure ............... 93
Crankshaft and Cylinder Block, Assembly Service . 86
Cylinder Block ........................... 89
Cylinder Head ........................... 78
Cylinder Head and Camshaft Service ......... 75
Engine Assembly ......................... 69
Engine Lubrication System ................. 91
Engine Mounts .......................... 68 Engine Specifications
..................... 95
General Information ....................... 66
Oil Filter and Bracket ..................... 94
Oil Pan ................................ 92
Oil Pump Service ........................ 92
Piston and Connecting Rod Assembly Service . . . 82
Timing Belt InspectionÐIn Vehicle ............ 72
Timing Belt Service ....................... 72
Valve Service ........................... 80
GENERAL INFORMATION
ENGINE IDENTIFICATION NUMBER OR CODE
The engine identification number is located on the
rear of the cylinder block just below the cylinder
head (Fig. 1). BLOCK: The cylinder block is a light weight de-
sign created by reducing thickness in many parts
and a short 10 mm (3/8 inch) block skirt. High rigid-
ity is provided with ribs cast in the outer wall, a full
length water jacket, and a monoblock or beam type, main bearing cap. This single unit four bearing cap
is designed to control vibration of the cylinder block
partition walls.
CRANKSHAFT: A six throw, five weight crank-
shaft is supported by four main bearings with num-
ber three being the thrust bearing. The six separate
connecting rod throws pins reduce torque fluctua-
tions while a torsional vibration damper is used to
control torsion caused vibration of the crankshaft.
Rubber lipped seals are used at front and rear. The
front seal is retained in the oil pump case and the
rear is retained in a block-mounted housing.
3.0L ENGINE
9 - 66 3.0L ENGINE Ä
Page 1855 of 2438
The PCM adjusts ignition timing based on the fol-
lowing inputs.
² engine coolant temperature
² engine speed (distributor pick-up)
² manifold absolute pressure
² throttle position
The Automatic Shut Down (ASD) and Fuel Pump
relays are mounted externally, but turned on and off
by the PCM through the same circuit. The distributor pick-up signal is sent to the PCM.
If the PCM does not receive a distributor signal
within approximately one second of engine cranking,
the ASD relay and fuel pump relay are deactivated.
When these relays are deactivated, power is shut off
to the fuel injector, ignition coil, oxygen sensor heat-
ing element and fuel pump. The PCM contains a voltage converter that
changes battery voltage to a regulated 8.0 volts. The
8.0 volts power the distributor pick-up and vehicle
speed sensor. The PCM also provides a 5.0 volts sup-
ply for the coolant temperature sensor, manifold ab-
solute pressure sensor and throttle position sensor.
AIR CONDITIONING SWITCH SENSE (AA, AG, AJ
BODY)ÐPCM INPUT
When the air conditioning or defrost switch is in
the ON position and the low pressure and high pres-
sure switches are closed, the PCM receives an input
for air conditioning. After receiving this input, the
PCM activates the A/C compressor clutch by ground-
ing the A/C clutch relay. The PCM also adjusts idle
speed to a scheduled RPM to compensate for in-
creased engine load.
AIR CONDITIONING SWITCH SENSE (AC
BODY)ÐPCM INPUT
When the air conditioning or defrost switch is in
the ON position and the low pressure, high pressure
and ambient temperature switches are closed, the
PCM receives an input for air conditioning. After re-
ceiving this input, the PCM activates the A/C com-
pressor clutch by grounding the A/C clutch relay.
The PCM also adjusts idle speed to a scheduled RPM
to compensate for increased engine load.
BATTERY VOLTAGEÐPCM INPUT
The PCM monitors the battery voltage input to de-
termine fuel injector pulse width and generator field
control. If battery voltage is low, the PCM will in-
crease injector pulse width.
BRAKE SWITCHÐPCM INPUT
When the brake switch is activated, the PCM re-
ceives an input indicating that the brakes are being
applied. After receiving this input the PCM main-
tains idle speed to a scheduled RPM through the idle
air control motor. The brake switch is mounted on
the brake pedal support bracket.
ENGINE COOLANT TEMPERATURE SENSORÐPCM
INPUT
The coolant temperature sensor is a variable resis-
tor with a range of -40É to 265É. The sensor is in-
stalled next to the thermostat housing. The PCM supplies 5.0 volts to the coolant temper-
ature sensor. The sensor provides an input voltage to
the PCM (Fig. 3). As coolant temperature varies, the
sensors resistance changes, resulting in a different
input voltage to the PCM. The PCM demands slightly richer air-fuel mixtures
and higher idle speeds until the engine reaches nor-
mal operating temperature. This sensor is also used for cooling fan control.
DISTRIBUTOR PICK-UPÐPCM INPUT
The distributor pick-up provides two inputs to the
PCM. From one input the PCM determines RPM (en-
gine speed). From the other input it derives crank-
shaft position. The PCM regulates injector
synchronization and adjusts ignition timing and en-
gine speed based on these inputs. The distributor pick-up contains two signal gener-
ators. The pick-up unit consists of 2 light emitting
diodes (LED), 2 photo diodes, and a separate timing
disk. The timing disk contains two sets of slots. Each
set of slots rotates between a light emitting diode
and a photo diode (Fig. 4). The inner set contains 6
large slots, one for each cylinder. The outer set con-
tains several smaller slots. The outer set of slots on the rotating disk repre-
sents 2 degrees of crankshaft rotation. Up to 1200
engine RPM, the PCM uses the input from the outer
set of slots to increase ignition timing accuracy. The outer set of slots contains a 10 degree flat spot
(Fig. 5). The flat spot tells the PCM that the next
piston at TDC will be number 6. The position of each
piston is referenced by one of the six inner slots (Fig.
5). As each slot on the timing disk passes between the
diodes, the beam from the light emitting diode is in-
Fig. 3 Coolant Temperature Sensor
Ä FUEL SYSTEMS 14 - 115