display CHEVROLET DYNASTY 1993 Workshop Manual

Perform cluster Self Diagnostic Test to determine
whether problem is within cluster or outside of clus-
ter. Refer to Fig. 24 and 25.
Successful completion of the SELF DIAGNOSTIC
TEST indicates that the problem is in the wiring,
connectors or sensors out side of the cluster.
CLUSTER ASSEMBLY REMOVAL
The electronic cluster which is serviced as an as-
sembly is removed with the same procedure as the
conventional cluster.
CONDITION: CLUSTER DISPLAYS DO NOT ILLUMINATE AFTER VEHICLE IS STARTED
(1) Check fuses and verify battery and ignition
voltage at cluster connector. (2) Check ground from cluster connector to instru-
ment panel ground stud.
SWITCH AND PANEL COMPONENT SERVICE
HEADLAMP SWITCH
The headlamp switch is located on the left side of
the switch pod. The switch controls the headlamps,
parking lamps, fog lamps and instrument light dim- ming. If any of the switches require replacement the
entire headlamp switch assembly must be replaced
(Fig. 26 and 27).
REMOVAL
(1) Remove switch pod assembly from the instru-
ment panel. DO NOT attempt to remove instrument
cluster dimmer switch or wiper delay switch knob,
they are not removable. (2) Remove turn signal switch lever by pulling
straight out of switch pod. (3) Remove screws from bottom of switch pod.
(4) Separate inner and outer switch pod halves and
remove turn signal switch to gain access to screw. (5) Remove five inner switch pod panel screws and
3 screws from underneath the switch pod. Separate
the inner bezel from the outer bezel. (6) Remove switch mounting screws before discon-
necting linkage. (7) Disconnect switch linkage from buttons. Pull
the linkage straight up from the switch/button to dis-
engage it and remove switch.
Fig. 23 Mechanical Cluster Lamp Location
Ä INSTRUMENT PANEL AND GAUGES 8E - 51

AP BODY INDEX
page page
Cluster and Gauge Service and Testing ....... 58
Gauges ................................ 61
General Information ....................... 58 Instrument Panel Replacement
.............. 72
Interior Lamp Replacement ................. 73
Switch and Panel Component Service ......... 67
GENERAL INFORMATION
INSTRUMENT CLUSTER
There are two conventional instrument cluster as-
semblies available. The clusters incorporates mag-
netic type gauges and an electronically driven
speedometer and odometer assembly (Fig. 1 and 2).
MAGNETIC GAUGES
All gauges on the AP Body clusters are the mag-
netic type gauges. When the ignition switch is in the
OFF position each gauge, except for the voltmeter
and tachometer will show a reading. However, the
readings are only accurate when the ignition switch
is in the ON position.
TACHOMETER DRIVE MODULE
The tachometer drive module is an electronic mod-
ule used to drive the magnetic tachometer in the
high line cluster. This module is located on top of the instrument
cluster.
ELECTRONIC DIGITAL CLOCK
The electronic digital clock is in the radio. The
clock and radio each use the display panel built into
the radio. A digital readout indicates the time in
hours and minutes whenever the ignition switch is in
the ON or ACC position. When the ignition switch is in the OFF position, or
when the radio frequency is being displayed, time
keeping is accurately maintained. The procedure for setting the clock varies slightly
with each radio. The correct procedure is described
under the individual radio operating instructions re-
fer to the Sound Systems Manual supplied with the
vehicle.
WARNING LAMPS AND INDICATOR LIGHTS
The instrument cluster has warning and indicators
lamps for eight different systems:
² Low oil pressure
² Brake warning
² Seat belt warning
² Malfunction indicator (check engine) lamp
² Air Bag
² High beam indicator
² Right and left turn signals.
² Anti-lock (ABS)
CLUSTER AND GAUGE SERVICE AND TESTING
CAUTION: Disconnect the negative battery cable
before servicing the instrument panel. When power
is required for test purposes, reconnect battery ca-
ble for test only. Disconnect the negative battery
cable after test and before continuing service pro-
cedures.
SENDING UNIT TEST
Check for a defective sending unit or wiring, when
a problem occurs with a cluster gauge. Do this before
disassembling the cluster. (1) Sending units and wiring can be checked by
grounding the connector leads, at the sending unit,
in the vehicle. (2) With the ignition in the ON position, a
grounded input will cause the fuel or temperature
gauge to read at or above maximum.
Fig. 1 Instrument Cluster With Tachometer
Fig. 2 Instrument Cluster Without Tachometer
8E - 58 INSTRUMENT PANEL AND GAUGES Ä

² If no short to ground at connector, check speaker
resistance at amplifier connector for an reading of
three to five ohms.
² If resistance is OK, refer to Radio Diagnosis. If ra-
dio checks OK, replace amplifier.
² If resistance is less than three ohms check
speaker. Check across the speaker connector if less
than three ohms replace speaker. If resistance is OK
repair wires
CONDITION: MECHANICAL NOISE DISTORTION
² Check trim for loose parts and speaker attach-
ments for buzzes
² Remove speaker still connected and listen for dis-
tortion. Distortion replace speaker.
CONDITION: ONE SPEAKER NON-OPERATIVE
² Remove output signal connector from amplifier
and check for three to five ohms resistance to the
non-operative speaker. Refer to Fig. 34 for the appro-
priate pin numbers.
² If resistance is less than three ohms, test speaker
for resistance.
² If OK repair wire. If not replace speaker.
CONDITION: ALL SPEAKERS NON-OPERATIVE
²Check radio for being ON, are the display lights
on
² Radio not ON, refer to Radio Diagnosis
² Check Amplifier Connectors and wires for proper
connection
² Check pin 9 and pin 27 for battery voltage
² If voltage OK replace amplifier ²
If pin 27 has battery voltage and pin 9 has 0 volt-
age. Refer to Power Antenna Diagnosis and test volt-
age at antenna relay.
² If pin 9 has battery voltage and pin 27 has 0 volt-
age. Check pin 27 for short to ground.
² If shorted to ground repair wire
² If no short to ground check fuse cavity number 16
for blown fuse.
² If fuse blows again replace amplifier
RELAY/CHOKEÐINFINITY SPEAKER
If the audio system is lacking bass, check for con-
tinuity across the relay and choke connectors. If no
continuity, replace relay/choke assembly (Fig. 35).
LOCATION
(1) AA and AP Bodies, attached to the reinforce-
ment above glove box. (2) AG Body, attached to the dimmer module bay-
onet bracket on the bulkhead behind the glove box.
Fig. 35 Relay/Choke Assembly
Ä AUDIO SYSTEM 8F - 29

COMPACT DISC PLAYER
WARNING: USE OF THE CONTROLS, ADJUST-
MENTS, OR SERVICE PROCEDURES NOT SPECI-
FIED HERE OR IN THE OWNER MANUAL MAY
RESULT IN HAZARDOUS RADIATION EXPOSURE.
REPAIR PROCEDURES SHOULD ONLY BE PER-
FORMED BY A TRAINED TECHNICIAN.
DIAGNOSIS TEST
Power to the compact disc player is supplied by the
radio through the CD interface cable. The compact
disc player will only work with the radio system
turned ON. When a compact disc is inserted with the
label side facing up, the disc is automatically loaded
and will begin to play. The CD player may eject the disc with a display of
E under the following conditions:
² The surface of the disc is dirty or wet
² The disc was inserted with the label side facing
down
² The disc is defective
² The CD player may skip or mute while playing a
disc under severe vibration conditions example pot
holes, railroad tracks, etc.
² If the CD player becomes too hot at temperatures
above 60ÉC (140 ÉF) the CD player will shut down
with a display of HOT until it cools down. Refer to
the Audio Diagnostic Charts.
COMPACT DISC PLAYER REPLACEMENT
With intergral compact disc player refer to Radio
Removal.
AJ BODY
(1) Remove center instrument panel bezel by pull-
ing toward the rear of the car. (2) Remove two screws attaching disc player to
console (Fig. 36). (3) Pull disc player out of console and disconnect
interface cable. (4) To install compact disc player, above the re-
moval procedures.
Fig. 36 Compact Disc Player
8F - 30 AUDIO SYSTEM Ä

Flexible fuel vehicles can operate on a mixture of
up to 85 percent methanol, 15 percent unleaded gas-
oline. These vehicles also operate on mixtures con-
taining a lower percentage of methanol or just pure
unleaded gasoline. Engine components which are required for safe op-
eration using fuel containing methanol alcohol are
identified by a standard green color and/or display
the statement methanol compatible imprinted on the
component. To ensure continued safe operation, these
components must be serviced only with genuine MO-
PAR replacement parts. Methanol compatible parts for the 2.5L FFV (Flex-
ible Fuel Vehicle) engine include, but are not limited
to; the valve stem oil seals, all piston rings, the oil
fill cap, the fuel injectors, fuel rail, fuel pressure reg-
ulator, hoses and the vacuum control harness hose. BLOCK: All four cylinder cast iron blocks have
cast-in recesses in the bottom of each cylinder bore to
provide connecting rod clearance; especially needed
for 2.5L engines. The bores are also siamese to min-
imize engine length. A coolant passage is drilled
cross-ways through the siamese section to enhance
between the bore cooling on some engine types. A
partial open deck is used for cooling and weight re-
duction with oil filter, water pump, and distributor
mounting bosses molded into the front (radiator side)
of the block. Nominal wall thickness is 4.5 mm. Five
main bearing bulkheads and a block skirt extending
3 mm below the crankshaft center line add to the
blocks high rigidity with light weight. CRANKSHAFT: A nodular cast iron crankshaft is
used in TBI engines. A forged steel crankshaft is
used in the Turbo III engine. All engines have 5 main bearings, with number 3 flanged to control
thrust. The 60 mm diameter main and 50 mm diam-
eter crank pin journals (all) have undercut radiuses
fillets that are deep rolled for added strength. To op-
timize bearing loading 4 counterweights are used.
Hydrodynamic seals (installed in diecast aluminum
retainers) provide end sealing, where the crankshaft
exits the block. Anaerobic gasket material is used for
retainer-to-block sealing. No vibration damper is
used. A sintered iron (TBI engine and steel billet
Turbo III engines) timing belt sprocket is mounted
on the crankshaft nose. This sprocket provides mo-
tive power; via timing belt to the camshaft and inter-
mediate shaft sprockets (also sintered iron (TBI
engine and steel billet Turbo III engines) providing
timed valve, distributor, and oil pump actuation. PISTONS: Some Chrysler pistons have cast-in
steel struts at the pin bosses for autothermic control.
All 2.2L and 2.5L piston tops have cuts to provide
valve clearance. Some pistons are dished to provide
various compression ratios. Standard 2.2L and 2.5L
engines are designed for 9.5:1 and 8.9:1 compression
ratios respectively. The 2.5L piston is dished and is a
lightweight design to enhance engine smoothness.
The 2.2L turbo III uses dished pistons providing a
8.3:1 compression ratio. All standard 2.2/2.5L and
2.5L FFV engines use pressed-in piston pins to at-
tach forged steel connecting rods, 2.2L turbo III en-
gine uses a full floating piston pin and connecting
rod assembly. PISTONS RINGS: The 2.2/2.5L engines share
common piston rings throughout, including molybde-
num filled top ring for reliable compression sealing
and a tapered faced intermediate ring for additional
cylinder pressure control. The 2.5L FFV engine fea-
ture all chrome rings for enhanced long term dura-
bility under multi-fueled conditions. CYLINDER HEAD: The cylinder head is cast alu-
minum with in-line valves. The 2.2/2.5L and 2.5L
FFV valves are arranged with alternating exhaust
and intake. The intake and exhaust ports are located
in the rearward, facing side of the head. The Turbo
III valves are arranged in two inline banks, with the
ports of the bank of two intake valves per cylinder
facing toward the radiator side of engine and ports of
the bank of two exhaust valve per cylinder facing to-
ward the dash panel. The intake ports feed fast-burn
design combustion chambers (2.2/2.5L and 2.5L FFV
only) with the spark plug located close to the center
line of the combustion chamber for optimum effi-
ciency. An integral oil gallery within the cylinder
head supplies oil to the hydraulic lash adjusters,
camshaft, and valve mechanisms. CAMSHAFT: The nodular iron camshaft has five
bearing journals (2.2/2.5L and 2.5L FFV). The Turbo
III employs dual camshafts that have nine bearing
journals. Flanges at the rear journal control cam-
Fig. 1 Engine Identification
Ä 2.2/2.5L ENGINE 9 - 9

CAUTION: When using the ASD Fuel System Test,
the Auto Shutdown (ASD) Relay remains energized
for either 7 minutes, until the test is stopped, or un-
til the ignition switch is turned to the Off position.
(4) Place the ignition key in the ON position. Us-
ing the DRBII scan tool, access ASD Fuel System
Test. The ASD Fuel System Test will activate the
fuel pump and pressurize the system. If the gauge reads the pressure shown in the Fuel
System Pressure chart, further testing is not re-
quired. If pressure is not correct, record the pressure
and remove gauge. If pressure is below specifications, proceed to Fuel
System Pressure Below Specifications . If pressure
is above specifications, proceed to Fuel System
Pressure Above Specifications .
Fuel System Pressure Below Specifications
If the fuel pressure reading in step (4) was below
specifications, test the system according to the fol-
lowing procedure.
WARNING: RELEASE FUEL SYSTEM PRESSURE
BEFORE DISCONNECTING A FUEL SYSTEM HOSE
OR COMPONENT.
(a) Perform Fuel Pressure Release procedure.
(b) Install Fuel Pressure Gauge C-4799 and Fuel
Pressure Adapter 6433 in the fuel supply line (Fig.
7) between the fuel tank and fuel filter. (c) Using the DRBII scan tool, with the ignition
key in the ON position, repeat the ASD Fuel Sys-
tem Test.
² If pressure is at least 5 psi higher than reading
recorded in step (4), replace fuel filter. ² If no change is observed, gently the squeeze re-
turn hose. If fuel pressure increases, replace pressure
regulator. If the gauge reading does not change while
squeezing the return hose, the problem is either a
plugged inlet strainer or defective fuel pump. Fuel System Pressure Above Specifications If the fuel pressure reading in step (4) was above
specifications test the system according to the follow-
ing procedure.
WARNING: FUEL SYSTEM PRESSURE MUST BE
RELEASED BEFORE A FUEL SYSTEM HOSE OR
COMPONENT IS DISCONNECTED.
(a) Perform Fuel Pressure Release procedure.
(b) Install Fuel Pressure Gauge C-4799 and Fuel
Pressure Adapter 6433 in the fuel supply line be-
tween the fuel tank and fuel filter (Fig. 7). (c) Remove the fuel return line hose from the
fuel pump at fuel tank. Connect Fuel Pressure Test
Adapter 6541 to the return line (Fig. 8). Place the
other end of adapter 6541 into an approved gaso-
line container or a container approved for gasoline/
methanol mixtures (minimum 2 gallon size). All
return fuel will flow into container. (d) Using the DRBII scan tool, with the ignition
key in the ON position, repeat the ASD Fuel Sys-
tem Test.
² If pressure is now correct, replace fuel pump as-
sembly. ²
If pressure is still above specifications, remove fuel
return hose from chassis fuel tubes (at engine). Attach
Fuel Pressure Test Connect Adapter 6541 to the fuel re-
turn hose and place other end of hose in clean approved
gasoline container or a container approved for metha-
nol/gasoline mixtures (Fig. 9). Repeat test. If pressure is
now correct, check for restricted fuel return line. If no
change is observed, replace fuel pressure regulator.
MECHANICAL MALFUNCTIONS
Mechanical malfunctions are more difficult to diag-
nose with this system. The powertrain control mod-
ule (PCM) compensates for some mechanical
malfunctions. If engine performance problems are en-
countered, and no fault codes are displayed, the prob-
lem may be mechanical rather than electronic.
FUEL PUMP MODULE REMOVAL
WARNING: RELEASE FUEL SYSTEM PRESSURE
BEFORE SERVICING FUEL SYSTEM COMPONENTS.
WHEN SERVICING FLEXIBLE FUEL VEHICLES,
WEAR METHANOL RESISTANT GLOVES AND EYE
PROTECTION AND AVOID BREATHING FUMES. DO
NOT ALLOW METHANOL/GASOLINE MIXTURES TO
CONTACT SKIN. SERVICE VEHICLES IN WELL VEN-
TILATED AREAS AND AVOID IGNITION SOURCES.
NEVER SMOKE WHILE SERVICING THE VEHICLE.
Remove the fuel tank to service the fuel pump. Re-
fer to Fuel Tank Section for fuel tank removal. (1) Using a hammer and a brass drift punch care-
fully tap lock ring counter clockwise to release pump
(Fig. 11).
Fig. 10 Fuel Pressure Gauge and Adapter
14 - 8 FUEL SYSTEMS Ä

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

2.2L/2.5L SINGLE POINT FUEL INJECTIONÐON-BOARD DIAGNOSTICS INDEX
page page
60-Way PCM Wiring Connector .............. 46
Circuit Actuation Test Mode ................ 45
Diagnostic Trouble Code Description .......... 42
General Information ....................... 41
High and Low Limits ...................... 42
Ignition Timing Procedure .................. 46 Monitored Circuits
........................ 41
Non-Monitored Circuits .................... 42
State Display Test Mode ................... 45
Systems Test ........................... 45
Throttle Body Minimum Air Flow Check Procedure.46
GENERAL INFORMATION
The powertrain control module (PCM) has been
programmed to monitor many different circuits of the
fuel injection system. If a problem is sensed with a
monitored circuit often enough to indicate an actual
problem, the PCM stores a fault. If the problem is re-
paired or ceases to exist, the PCM cancels the Diag-
nostic Trouble Code after 50 to 100 vehicle key on/off
cycles. Certain criteria must be met for a diagnostic trou-
ble code to be entered into powertrain control module
(PCM) memory. The criteria may be a specific range
of engine RPM, engine temperature, and/or input
voltage to the PCM. It is possible that a diagnostic trouble code for a
monitored circuit may not be entered into memory
even though a malfunction has occurred. This may
happen because one of the diagnostic trouble code
criteria for the circuit has not been met. For exam-
ple , assume that one of the diagnostic trouble code
criteria for a certain sensor circuit is that the engine
must be operating between 750 and 2000 RPM to be
monitored for a diagnostic trouble code. If the sensor
output circuit shorts to ground when engine RPM is
above 2400 RPM (resulting i n a 0 volt input to the
PCM) a diagnostic trouble code will not be entered
into memory. This is because the condition does not
occur within the specified RPM range. There are several operating conditions for which
the PCM does not monitor and set diagnostic trouble
codes. Refer to Monitored Circuits and Non-Moni-
tored Circuits in this section. Stored diagnostic trouble codes can be displayed by
cycling the ignition key On - Off - On - Off - On.
Also, the technician can display fault information us-
ing the DRB II scan tool. The DRBII scan tool con-
nects to the data link connector in the vehicle (Fig.
1,2or3).
MONITORED CIRCUITS
The powertrain control module (PCM) can detect
certain fault conditions in the fuel injection system. Open or Shorted Circuit - The PCM can deter-
mine if the sensor output (input to PCM) is within
proper range, and if the circuit is open or shorted. Output Device Current Flow
- The PCM senses
whether the output devices are hooked up. If there is
a problem with the circuit, the PCM senses whether
the circuit is open, shorted to ground, or shorted
high. Oxygen Sensor - The PCM can determine if the
oxygen sensor is switching between rich and lean
Fig. 1 Data Link Connector LocationÐAA and AP Vehicles
Fig. 2 Data Link Connector LocationÐAC Vehicles
Ä FUEL SYSTEMS 14 - 41

once the system has entered closed loop. Refer to
Modes of Operation in this section for an explanation
of closed loop operation.
NON-MONITORED CIRCUITS
The PCM does not monitor the following circuits,
systems and conditions that could have malfunctions
that result in driveability problems. Diagnostic trou-
ble codes may not be displayed for these conditions.
However, problems with these systems may cause di-
agnostic trouble codes to be displayed for other sys-
tems. For example, a fuel pressure problem will not
register a fault directly, but could cause a rich or
lean condition. This could cause an oxygen sensor
fault to be stored in the PCM. Fuel Pressure - Fuel pressure is controlled by the
fuel pressure regulator. The PCM cannot detect a
clogged fuel pump inlet filter, clogged in-line fuel fil-
ter, or a pinched fuel supply or return line. However,
these could result in a rich or lean condition causing
an oxygen sensor fault. Secondary Ignition Circuit - The PCM cannot
detect an inoperative ignition coil, fouled or worn
spark plugs, ignition cross firing, or open spark plug
cables. Engine Timing - The PCM cannot detect an incor-
rectly indexed timing chain, camshaft sprocket and
crankshaft sprocket. The PCM also cannot detect an
incorrectly indexed distributor. However, these could
result in a rich or lean condition causing an oxygen
sensor fault to be stored in the PCM. Cylinder Compression - The PCM cannot detect
uneven, low, or high engine cylinder compression. Exhaust System
- The PCM cannot detect a
plugged, restricted or leaking exhaust system. Fuel Injector Malfunctions - The PCM cannot
determine if the fuel injector is clogged, the pintle is
sticking or the wrong injector is installed. However,
these could result in a rich or lean condition causing
an oxygen sensor fault to be stored in the PCM. Excessive Oil Consumption - Although the PCM
monitors the exhaust stream oxygen content through
the oxygen sensor when the system is in closed loop,
it cannot determine excessive oil consumption. Throttle Body Air Flow - The PCM cannot detect
a clogged or restricted air cleaner inlet or filter ele-
ment. Evaporative System - The PCM will not detect a
restricted, plugged or loaded evaporative purge can-
ister. Vacuum Assist - Leaks or restrictions in the vac-
uum circuits of vacuum assisted engine control sys-
tem devices are not monitored by the PCM. However,
these could result in a MAP sensor fault being stored
in the PCM. PCM System Ground - The PCM cannot deter-
mine a poor system ground. However, a diagnostic
trouble code may be generated as a result of this con-
dition. PCM Connector Engagement - The PCM cannot
determine spread or damaged connector pins. How-
ever, a diagnostic trouble code may be generated as a
result of this condition.
HIGH AND LOW LIMITS
The powertrain control module (PCM) compares in-
put signal voltages from each input device with es-
tablished high and low limits that are programmed
into it for that device. If the input voltage is not
within specifications and other diagnostic trouble
code criteria are met, a diagnostic trouble code will
be stored in memory. Other diagnostic trouble code
criteria might include engine RPM limits or input
voltages from other sensors or switches that must be
present before a fault condition can be verified.
DIAGNOSTIC TROUBLE CODE DESCRIPTION
When a diagnostic trouble code appears, it indi-
cates the powertrain control module (PCM) has rec-
ognized an abnormal condition in the system.
Diagnostic trouble codes can be obtained from the
malfunction indicator lamp (instrument panel Check
Engine lamp) on the Instrument Panel or from the
DRBII scan tool. Diagnostic trouble codes indicate
the results of a failure but do not identify the failed
component directly.
Fig. 3 Data Link Connector LocationÐAG and AJ Vehicles
14 - 42 FUEL SYSTEMS Ä

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
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