Engine Controls - Tests W/codes - 2.3l Buick Skylark VII

INTRODUCTION

Most engine control problems are the result of mechanical breakdowns, poor electrical connections or damaged vacuum hoses. Before considering the computer system as a possible cause of problems, perform checks and inspections covered in appropriate BASIC TESTING article in this section. Failure to do so may result in lost diagnostic time.

If no faults were found while performing BASIC DIAGNOSTIC PROCEDURES, proceed with DIAGNOSTIC PROCEDURE under SELF-DIAGNOSTIC SYSTEM. If no fault codes are present and driveability problems exist, proceed to TESTS W/O CODES article in this section for diagnosis by symptom (i.e., ROUGH IDLE, NO START, etc.). If only intermittent codes are present, see INTERMITTENTS in TESTS W/O CODES article in this section.

SELF-DIAGNOSTIC SYSTEM

Note. Powertrain Control Module (PCM) may also be referred to as Electronic Control Module (ECM) in some diagnostic charts and figures. Terms are used interchangeably.

Control module is equipped with a self-diagnostic system, which detects system failures or abnormalities. When a malfunction occurs, control module will store a numerical code and, in most cases, illuminate SERVICE ENGINE SOON light located on instrument panel. SERVICE ENGINE SOON light is also referred to as the Malfunction Indicator Light (MIL). Malfunctions are recorded as hard failures or as intermittent failures.

Note. Models equipped with OBD II diagnostic systems may have additional diagnostic information and procedures available; however, to fully utilize information and procedures requires the use of a Tech 1 scan tester. See tester owners manual for additional information.

HARD FAILURES

Most hard failures cause SERVICE ENGINE SOON light to glow and remain on until malfunction is repaired. If light comes on and remains on (light may flash) during vehicle operation, cause of malfunction must be determined using diagnostic (code) charts. If a sensor fails, control module will use a substitute value in its calculations to continue engine operation. In this condition, vehicle is functional, but it will most likely display degraded driveability.

INTERMITTENT FAILURES

Intermittent failures cause SERVICE ENGINE SOON light to flicker or glow and go out about 10 seconds after intermittent fault goes away. Corresponding trouble code, however, will be retained in control module memory. If related fault does not reoccur within 50 engine starts, trouble code will be erased from control module memory. Intermittent failures may be caused by sensor, connector or wiring related problems. See INTERMITTENTS in TESTS W/O CODES article in this section.

DIAGNOSTIC PROCEDURE

Diagnosis of computerized engine control system should be performed in following order

1. Ensure all engine systems not related to computer system are operating properly. DO NOT proceed with testing unless all other problems have been repaired. DIAGNOSTIC CIRCUIT CHECK must be performed before using trouble code charts. See «BASIC TESTING»(/buick/skylark/vii-1992-1998/remont/testing-diagnostics/#engine-controls-basic-testing) article in this section.
2. If trouble codes were displayed, determine whether codes are hard or intermittent trouble codes. Hard codes will cause SERVICE ENGINE SOON light to glow continuously while engine is running. See «HARD OR INTERMITTENT TROUBLE CODE DETERMINATION»(/buick/skylark/vii-1992-1998/remont/testing-diagnostics/#engine-controls-tests-wcodes-23l__hard-or-intermittent-trouble-code-determination) . For diagnosing hard codes, proceed to appropriate trouble code chart. For diagnosing intermittent codes, proceed to INTERMITTENTS in «TESTS W/O CODES»(/buick/skylark/vii-1992-1998/remont/testing-diagnostics/#engine-controls-tests-wo-codes) article in this section.
3. If no trouble codes are present and a driveability problem exists, refer to SYMPTOMS in «TESTS W/O CODES»(/buick/skylark/vii-1992-1998/remont/testing-diagnostics/#engine-controls-tests-wo-codes) article in this section. Doing so will help identify proper system or component to check in «SYSTEM/COMPONENT TESTS - 2.3L»(/buick/skylark/vii-1992-1998/remont/testing-diagnostics/#engine-controls-systemcomponent-tests-23l) article in this section.
4. After necessary repairs are made, clear trouble codes, verify vehicle will enter "closed loop" operation and ensure code does not reset.

Note. For specific information on retrieving codes using a scan tester, refer to user and reference manuals supplied with tester.

Note. Field service mode check can only be performed on vehicles equipped with 12-pin DLC with a wire present in test terminal "B". See DATA LINK CONNECTOR (DLC) TEST TERMINALS .

DATA LINK CONNECTOR (DLC) TEST TERMINALS

Scheme 3

READING TROUBLE CODES

Control module stores component failure information under a related trouble code which can be recalled for diagnosis and repair. Trouble codes may be read by counting flashes of SERVICE ENGINE SOON light (some models) or by reading digital display on a scan tester. Scan tester is faster to use, more accurate and capable of reading information which otherwise would necessitate testing individual control module and sensor/solenoid connector terminals using a digital voltmeter. See SCAN TESTER USAGE and SCAN DATA .

Note. When using most scan testers, a time delay exists between serial data updates. For instantaneous response, a digital voltmeter must be used.

If scan tester is not available, reading flashes of SERVICE ENGINE SOON light is possible by grounding diagnostic test terminal "B" (if a wire is present) of DLC with ignition on and engine off. (Scheme 3) For example, "FLASH, FLASH, pause, FLASH, longer pause" identifies Code 21. First series of flashes is first digit of trouble code. Second series of flashes is second digit of trouble code. Trouble codes are displayed starting with lowest numbered code. Each code is displayed 3 times. Codes will continue to repeat as long as DLC test terminal is grounded.

TROUBLE CODE DEFINITION

TROUBLE CODE DEFINITION

HARD OR INTERMITTENT TROUBLE CODE DETERMINATION

During any diagnostic procedure, determine if codes are hard failure codes or intermittent failure codes. Diagnostic charts will not usually help analyze intermittent codes. To determine hard codes and intermittent codes

1. Enter diagnostic mode. Read and record all stored trouble codes. Exit diagnostic mode, and clear trouble codes. See «CLEARING TROUBLE CODES»(/buick/skylark/vii-1992-1998/remont/testing-diagnostics/#engine-controls-tests-wcodes-23l__clearing-trouble-codes) .
2. Apply parking brake, and place transmission in Neutral or Park. Block drive wheels, and start engine. SERVICE ENGINE SOON light should go out. Run warm engine at specified curb idle for 2 minutes and note SERVICE ENGINE SOON light.
3. If SERVICE ENGINE SOON light comes on, enter diagnostic mode. Read and record trouble codes. This will reveal hard failure codes. Oxygen sensor related codes may require a road test to reset hard failure after trouble codes were cleared.
4. If SERVICE ENGINE SOON light does not come on, all stored trouble codes were intermittent failures, except as noted above.

Note. Trouble codes will be recorded at various operating times. Some codes require operation of that sensor or switch for 5 seconds; others require operation for 5 minutes or longer at normal operating temperature, vehicle speed and load. Therefore, some codes may not set in a service bay operational mode and may require road testing vehicle in order to duplicate conditions under which code will set.

CLEARING TROUBLE CODES

To clear trouble codes from memory, either to determine if malfunction will occur again or after making necessary repairs, disconnect power supply to PCM for at least 30 seconds or clear codes using a scan tester with code clearing capability.

PCM LOCATION

On most models, engine control module is located behind right or left side of dash, behind right or left kick panel or on left or right side of engine compartment. For more precise location, see COMPONENT LOCATIONS in SYSTEM/COMPONENT TESTS - 2.3L article in this section.

Diagnostic Aids

Diagnostic aids (located in many trouble code charts) are additional tips used to help diagnose trouble codes when inspected circuit is okay. Diagnostic aids may help lead to a definitive solution to trouble code problem.

Field Service Mode Check (If Available)

If DLC test terminal "B" is grounded with engine running, SERVICE ENGINE SOON light will indicate operational mode of engine. This test confirms proper operation of fuel system and verifies "closed loop" operation. Clear codes and perform this test after any repair is completed. Most models require the use of a scan tester to enter field service mode. See FIELD SERVICE MODE CHECK in the BASIC TESTING article in this section.

Note. Vehicles utilizing a 16-terminal DLC or 12-terminal DLC with terminal "B" not used, must use a scan tester for retrieving codes or enter Field Service Mode.

SPECIAL TOOLS (DIAGNOSTIC)

Note. A scan tester plugged into DLC may be used to read trouble codes and check voltages in system on serial data line. On most models scan tester is REQUIRED to retrieve vehicle information. For additional information, see SCAN TESTER USAGE and SCAN DATA .

Computerized engine control system is most easily diagnosed using scan tester; however, other tools may aid in diagnosing problems if a scan tester is unavailable. These tools are a tachometer, test light, ohmmeter, digital voltmeter with a 10-megohm input impedance (minimum), vacuum pump, vacuum gauge, fuel injector test lights and 6 jumper wires 6" long (one wire with female connectors at both ends, one wire with male connectors at both ends and 4 wires with male and female connectors at opposite ends). A test light, rather than a voltmeter, must be used when indicated by a diagnostic chart. In addition, special jumper harnesses or testers may be required by manufacturer to facilitate diagnosis.

SCAN TESTER USAGE

Note. Before connecting scan tester to vehicle, diagnostic system should be checked to determine if system is operating properly and if information received will be accurate. This is done by performing DIAGNOSTIC CIRCUIT CHECK or ON-BOARD DIAGNOSTIC SYSTEM CHECK located in BASIC TESTING article in this section. If vehicle does not pass diagnostic check, information received may be invalid.

Scan tester is a specialized tester which, when plugged into DLC, can be used to diagnose on-board computer control systems by providing instant access to circuit voltage information without need to crawl under dash or hood to backprobe sensors and connectors.

Scan tester cuts down diagnostic time dramatically by furnishing input data (voltage signals) which can be compared to specification parameters. See SCAN DATA . They may also furnish information on output device (solenoids and motors) status. However, status parameters only indicate output signals have been sent to devices by control module; they do not indicate whether devices have responded properly to signal. Verify proper response at output device using a voltmeter or test light.

A problem may exist even if trouble codes are not present. About 80 percent of driveability problems occur without trouble codes. Sensors that are out of calibration will not set a trouble code but will cause driveability problems.

Using a scan tester is the easiest method of checking sensor specifications and other data parameters. Tester is also useful in finding intermittent wiring problems by wiggling wiring harnesses and connections (key on, engine off) while observing data parameters. See SCAN DATA .

Note. If erroneous voltage signals are suspected, verify tester information using a digital voltmeter and wiring schematic. If non-existent codes are displayed, DO NOT use scan tester for diagnosis. Contact tester manufacturer for additional information.

SCAN DATA

Note. Information contained in SCAN DATA is typical of readings taken on vehicle with engine idling, upper radiator hose hot, closed throttle, transmission in Park or Neutral, "closed loop" status achieved and all accessories off (except as noted in tables). Data parameters are updated a minimum of every 1 1/4 seconds, more often on most models. Not all devices and systems are used on all models; following lists only represent most commonly used parameters. For additional information, refer to owner manual furnished with tester.

SCAN DATA

ECM/PCM CODE CHARTS

Note. In following diagnostic tests, schematics and illustrations are courtesy of General Motors Corp.

CODE 13, OPEN OXYGEN SENSOR CIRCUIT

Code will set if Codes 21 and 22 are not set, engine is at normal operating temperature, oxygen sensor voltage is constant within a specified range (.35-.55 volt), throttle angle is greater than idle, a precalibrated amount of time has elapsed since start-up and all conditions have existed for a precalibrated amount of time. Most likely causes of code are: open sensor signal (high) circuit, faulty PCM connection, faulty PCM, faulty oxygen sensor connection or faulty oxygen sensor.

Note. Test numbers refer to numbers on diagnostic chart.

1. This tests if problem still exists. Vehicle cannot enter "closed loop" mode if oxygen sensor circuit is open. Code indicates an open in O2 sensor circuit (steady .35-.55 volt).
2. Determines if oxygen sensor, wiring or control module is at fault. If wiring is good, grounding oxygen sensor wire will cause .45 volt reference supplied by control module to pull low.
3. This tests oxygen sensor circuit wiring. Use only a high impedance (10-megohm minimum) digital voltmeter.

Control module will not go into closed loop if code is set. Code may set if vehicle runs out of fuel or stalls while vehicle is in motion. If oxygen sensor ground becomes loose, a false oxygen sensor reading will occur. This can result in a Code 13 being set. On models equipped with an oxygen sensor heating element, element resistance should be 3.5-14.0 ohms.

CODE 13 PCM TERMINAL & CIRCUIT WIRING IDENTIFICATION

Code 13 Schematic (2.3L) Open Oxygen Sensor Circuit. Scheme 4

Code 13 Diagnostic Flow Chart (2.3L) Open Oxygen Sensor Circuit. Scheme 5

CODE 14, COOLANT TEMP SENS SGNL VLTGE LOW (HI TEMP INDICATED)

Code will set if PCM sees an extremely high temperature signal (low voltage). Most likely causes of code are: sensor signal circuit shorted to ground, faulty coolant temperature sensor or faulty PCM.

Note. This chart assumes engine cooling system is functioning properly (not overheating). Test numbers refer to numbers on diagnostic chart.

1. This checks if conditions for code still exist.
2. This tests for grounded sensor signal line between control module and coolant sensor.

After engine is started, temperature should rise steadily to about 90°C and then stabilize when thermostat opens. At normal operating temperature, signal voltage at control module terminal should be 1.5-2.0 volts. Check sensor for shifted calibration by using sensor TEMPERATURE-TO-RESISTANCE VALUES table. When code is set, control module will turn on electric cooling fan(s) if equipped.

CODE 14 PCM TERMINAL & CIRCUIT WIRING IDENTIFICATION

TEMPERATURE-TO-RESISTANCE VALUES (Measure resistance across sensor terminals)

1. For shared sensor ground tie-offs, see appropriate wiring diagram in WIRING DIAGRAMS section.

Code 14 Schematic (2.3L) Coolant Temperature Sensor Signal Voltage Low (High Temp. Indicated). Scheme 6

Code 14 Diagnostic Flow Chart (2.3L) Coolant Temperature Sensor Signal Voltage Low (High Temp. Indicated). Scheme 7

CODE 15, COOLANT TEMP SENSOR SIGNAL VOLTAGE LOW

Code indicates control module has seen high resistance (high monitored voltage) in coolant sensor circuit. This could be due to high resistance (cold temperature) or high voltage at coolant sensor terminal at control module for a precalibrated period of time. Most likely causes of code are: open sensor signal circuit, open sensor ground circuit (not allowing path to ground for 5-volt reference), faulty sensor connection, faulty sensor, faulty PCM connection or faulty PCM.

Note. Test numbers refer to numbers on diagnostic chart.

1. This checks if conditions for code still exist.
2. This test simulates a low voltage condition. If control module recognizes low voltage signal, scan tester will display greater than about 130°C. This indicates control module and wiring are not at fault.
3. This test determines if coolant sensor ground or signal circuit is open.

After engine is started, temperature should rise steadily to about 90°C and then stabilize when thermostat opens. At normal operating temperature, signal voltage at control module terminal should be 1.5-2.0 volts. Check sensor for shifted calibration by using sensor TEMPERATURE-TO-RESISTANCE VALUES table. When code is set, control module will turn on electric cooling fan(s) if equipped.

CODE 15 PCM TERMINAL & CIRCUIT WIRING IDENTIFICATION

TEMPERATURE-TO-RESISTANCE VALUES (Measure resistance across sensor terminals)

1. For shared sensor ground tie-offs, see appropriate wiring diagram in WIRING DIAGRAMS section.

Code 15 Diagnostic Flow Chart (2.3L) Coolant Temp Sensor Signal Voltage Low. Scheme 8

CODE 19, INTERMITTENT 7X SIGNAL

The ignition control module sends a reference signal to the PCM 7 times per crankshaft revolution to indicate crankshaft position and RPM so that the PCM can determine when to pulse the ignition coils and control ignition timing. A 5-volt reference is supplied to the PCM from terminal "G" of the ignition module. This 5-volt reference signal is monitored by the PCM. The ignition module pulls this signal low based upon 7X reference pulses. The seventh pulse is used for crankshaft position (sync) reference. Code 19 is set if the PCM misses at least 20 sync pulses within 4 minutes and 16 seconds.

Note. Test numbers refer to numbers on diagnostic chart.

1. Determines if PCM recognizes a problem. If Code 19 does not set, problem is intermittent.
2. When a resync occurs, engine will stumble. This step determines if component connections or circuit is faulty.
3. Operating non-engine related components may generate electromagnetic interference which may cause a resync.

Inspect harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, poor terminal-to-wire connections or damaged harness. Perform intermittent check by monitoring circuit and code status while wiggling related wiring and connectors. If failure is induced, monitored circuit status will change rapidly and/or related code will set.

If vehicle has non-standard electrical equipment (CB radios, 2-way radios, etc.) check to see if their operation may be causing a 7X resync which may set Code 19. If a "cranks but won't start" condition has existed, code may be due to 20 attempted starts without turning off ignition switch.

Code 19 Schematic (2.3L) Intermittent 7X Signal. Scheme 9

Code 19 Diagnostic Flow Chart (2.3L) Intermittent 7X Signal. Scheme 10

CODE 21, THROTTLE POSITION SENSOR SIGNAL VOLTAGE HIGH

Code will set if engine is idling (closed throttle), MAP value is low, a MAP code is not set and PCM sees high TP sensor voltage. Most likely causes for code are: TP sensor signal circuit shorted to voltage, open sensor ground circuit, faulty sensor connection, faulty TP sensor or faulty PCM.

Note. Test numbers refer to numbers on diagnostic chart.

1. This test checks if code is result of a hard failure or an intermittent condition.
2. This test simulates a low-voltage condition. If control module recognizes change of state, control module and wiring are okay.
3. This step isolates a faulty sensor, control module or open sensor ground circuit. If sensor ground is shared by another sensor, an accompanying code related to that sensor may exist.

A scan tester displays throttle position in volts. Closed throttle voltage should be low. Voltage should increase gradually to about 4.5 volts at a steady rate as throttle angle is increased. If code is intermittent, see INTERMITTENTS in TESTS W/O CODES article in this section.

CODE 21 PCM TERMINAL & CIRCUIT WIRING IDENTIFICATION

1. For shared sensor ground tie-offs, see appropriate wiring diagram in WIRING DIAGRAMS section.

Code 21 Schematic (2.3L) Throttle Position Sensor Signal Voltage High. Scheme 11

Code 21 Diagnostic Flow Chart (2.3L) Throttle Position Sensor Signal Voltage High. Scheme 12

CODE 22, THROTTLE POSITION SENSOR SIGNAL VOLTAGE LOW

Code will set if engine is running and TP sensor voltage is lower than base idle voltage (auto zero voltage). Most likely causes of code are: TP sensor signal circuit open or shorted to ground, 5-volt reference open or shorted to ground (should also set other codes), faulty sensor connection, faulty sensor, faulty PCM connection or faulty PCM.

Note. Test numbers refer to numbers on diagnostic chart.

1. This test checks if code is result of a hard failure or an intermittent condition.
2. This test simulates high voltage conditions. If control module recognizes change of state, control module and wiring are okay.
3. This simulates a high signal voltage to check for an open in TP sensor signal line to control module. Scan tester should recognize this signal and display high TP sensor voltage.

A scan tester displays throttle position in volts. Closed throttle voltage should be low. Voltage should increase gradually to about 4.5 volts at a steady rate as throttle angle is increased. If code is intermittent, see INTERMITTENTS in TESTS W/O CODES article in this section.

CODE 22 PCM TERMINAL & CIRCUIT WIRING IDENTIFICATION

1. For shared sensor ground tie-offs, see appropriate wiring diagram in WIRING DIAGRAMS section.

Code 22 Diagnostic Flow Chart (2.3L) Throttle Position Sensor Signal Voltage Low. Scheme 13

CODE 23, IAT SENSOR SIGNAL VOLTAGE HIGH (LOW TEMP INDICATED)

Code will set if engine has been running for a precalibrated period of time, has reached operating temperature and signal voltage indicates a low intake air temperature (high voltage). Most likely causes of code are: open sensor signal circuit, open sensor ground circuit (not allowing path to ground for 5-volt reference), faulty sensor connection, faulty sensor, faulty PCM connection or faulty PCM.

Note. Test numbers refer to numbers on diagnostic chart.

1. Checks if code is result of a hard failure or an intermittent condition.
2. This simulates low voltage (high temperature) conditions. If scan tester displays a high temperature, control module and wiring are not at fault.
3. This checks for continuity of sensor signal and ground circuits using process of elimination. If ground circuit is shared by other sensors and ground circuit is open, accompanying codes related to those sensors may be present.

If engine is allowed to cool overnight, coolant and IAT sensor values should be close to each other when measured by scan tester. Code will result if signal and ground circuits become open. Check sensor for shifted calibration by using sensor TEMPERATURE-TO-RESISTANCE VALUES table.

CODE 23 PCM TERMINAL & CIRCUIT WIRING IDENTIFICATION

TEMPERATURE-TO-RESISTANCE VALUES (Measure resistance across sensor terminals)

1. For shared sensor ground tie-offs, see appropriate wiring diagram in WIRING DIAGRAMS section.

Code 23 Schematic (2.3L) IAT Sensor Signal Voltage High (Low Temp Indicated). Scheme 14

Code 23 Diagnostic Flow Chart (2.3L) IAT Sensor Signal Voltage High (Low Temp Indicated). Scheme 15

CODE 24, VEHICLE SPEED SENSOR

Speed sensor, which is a Permanent Magnet (PM) generator, provides control module with vehicle speed information. PM generator, mounted in transmission, produces a pulsing AC voltage signal whenever vehicle speed is greater than about 2 MPH. Voltage level and pulses increase with vehicle speed. Control module converts pulsing voltage to MPH, which is used by control module to calculate vehicle adjustments.

Note. Test numbers refer to numbers on diagnostic chart.

Note. Prior to testing Corvette for Code 24, disable ASR system.

1. PM generator only produces a voltage signal if drive wheels are turning greater than about 2 MPH.

A faulty or misadjusted park/neutral switch may set a false Code 24. Use scan tester to check for proper signal in Drive while wiggling shifter. Code 24 may set if vehicle is power braked (brakes applied and throttle depressed) for more than 10 seconds.

Code 24 Schematic (2.3L) Vehicle Speed Sensor. Scheme 16

Code 24 Diagnostic Flow Chart (2.3L) Vehicle Speed Sensor. Scheme 17

CODE 25, IAT SENSOR SIGNAL VOLTAGE LOW (HIGH TEMP INDICATED)

Code will set if intake air temperature is extremely high (sensor signal voltage low) for a precalibrated period of time. Most likely causes of code are: sensor signal circuit shorted to ground, faulty coolant temperature sensor or faulty PCM.

Note. Test numbers refer to numbers on diagnostic chart.

1. This checks if code is hard failure or intermittent condition.
2. This simulates low temperature (high resistance) conditions. If control module recognizes open circuit and scan tester displays temperature of less than about -30°C, control module and wiring are okay.

If engine is allowed to cool overnight, coolant temperature sensor and IAT sensor values should be close to each other when measured by a scan tester. A Code 25 will result if sensor signal circuit is shorted to ground. Check sensor for shifted calibration by using sensor TEMPERATURE-TO-RESISTANCE VALUES table.

CODE 25 PCM TERMINAL & CIRCUIT WIRING IDENTIFICATION

TEMPERATURE-TO-RESISTANCE VALUES (Measure resistance across sensor terminals)

1. For shared sensor ground tie-offs, see appropriate wiring diagram in WIRING DIAGRAMS section.

Code 25 Diagnostic Flow Chart (2.3L) IAT Sensor Signal Voltage Low (High Temp Indicated). Scheme 18

CODE 26, QUAD-DRIVER MODULE ERROR

PCM controls most components with electronic switches completing a ground circuit when actuated. Switches are arranged in groups of 4, called Quad-Driver Modules (QDMs), which can independently control up to 4 outputs (control module terminals). When an output is actuated, terminal is grounded and its voltage normally will be low. When an output is off, its terminal voltage will normally be high.

QDMs are fault-protected. If a relay or solenoid coil is shorted (having very low resistance) or if control side of circuit is shorted to voltage, too much current would be allowed into QDM. QDM senses this and turns driver off or QDM's internal resistance increases to limit current flow and protect QDM. Result is high output terminal voltage when it should be low. If circuit from battery voltage or component is open or control side of circuit is shorted to ground, terminal voltage will be low, even when output is turned off. Either of these conditions is considered to be a QDM fault.

Each QDM has a separate fault line to indicate presence of a current fault to control module central processor. A scan tester displays status of each of these fault lines as "low equals okay" or "high equals fault".

Note. Test numbers refer to numbers on diagnostic chart.

1. Checks to see if code was set as the result of a current or intermittent condition.
2. Checks MIL operation.
3. Checks TEMP/CHECK GAUGES light.

Tech 1 has the ability to command the MIL and TEMP/CHECK GAUGES light on and off. A faulty driver circuit or poor connection can result in setting of Code 26.

Code 26 Schematic (2.3L) Quad-Driver Module Error. Scheme 19

Code 26 Diagnostic Flow Chart (2.3L) Quad-Driver Module Error. Scheme 20

CODE 27, QUAD-DRIVER NO. 1 ERROR

PCM controls most components with electronic switches completing a ground circuit when actuated. Switches are arranged in groups of 4, called Quad-Driver Modules (QDMs), which can independently control up to 4 outputs (control module terminals). When an output is actuated, terminal is grounded and its voltage normally will be low. When an output is off, its terminal voltage will normally be high.

QDMs are fault-protected. If a relay or solenoid coil is shorted (having very low resistance) or if control side of circuit is shorted to voltage, too much current would be allowed into QDM. QDM senses this and turns driver off or QDM's internal resistance increases to limit current flow and protect QDM. Result is high output terminal voltage when it should be low. If circuit from battery voltage or component is open or control side of circuit is shorted to ground, terminal voltage will be low, even when output is turned off. Either of these conditions is considered to be a QDM fault.

Each QDM has a separate fault line to indicate presence of a current fault to control module central processor. A scan tester displays status of each of these fault lines as "low equals okay" or "high equals fault". Because of the brake and 3rd gear switches in the TCC circuit, Code 27 will set if QDM No. 1 is high for 20 seconds or more with battery voltage sensed at greater than 10.5 volts and TCC is commanded on.

Note. Test numbers refer to numbers on diagnostic chart.

1. Checks if code was set as a result of EVAP canister purge valve circuit.
2. Checks TCC operation.
3. Checks shift light operation.

Tech 1 has the ability to command EVAP purge valve and shift light on and off. Inspect harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, poor terminal-to-wire connections or damaged harness. Perform intermittent check by monitoring circuit and code status while wiggling related wiring and connectors. If failure is induced, monitored circuit status will change rapidly and/or related code will set.

Code 27 Schematic (2.3L) Quad-Driver No. 1 Error. Scheme 21

Code 27 Diagnostic Flow Chart (2.3L) Quad-Driver No. 1 Error. Scheme 22

CODE 28, QUAD-DRIVER 2

PCM controls most components with electronic switches which complete a ground circuit when turned ON. These switches are arranged in groups of 4, called Quad-Driver Modules (QDM's) which can independently control up to 4 outputs (control module terminals). When an output is ON the terminal is grounded and its voltage normally will be low. When an output is OFF, its terminal voltage normally will be high, except for the TCC, as noted below which depends on the brake and second gear TCC switches.

QDMs are fauly protected. If a relay or solenoid coil is shorted, having very low or zero resistance, or if the control side of the circuit is shorted to voltage, it would allow too much current into the QDM. The QDM senses this and the output turns OFF or its internal resistance increases to limit current flow and protect the QDM. The result is high output terminal voltage when it sould be low. If the circuit from positive battery voltage, or the component is open, or the control side of the circuit is shorted to ground, terminal voltage will be low, even when output is commanded OFF. Either of these conditions is considered to be a QDM fault.

QDM 2 has a fault line to indicate the presence of a current fault to the PCM's central processor. A scan tool displays the status of the fault line as LOW is okay and HIGH indicates a fault.

DTC 28 will set when

1. QDM 2 fault line C is HIGH for 20 seconds or more
2. Battery voltage is greater than 10.5 volts.

DTC 28 will clear when

1. The next ignition cycle is performed. NOTE: Test numbers refer to numbers on diagnostic chart.

1. This step checks the cooling fan circuit.
2. This step checks the A/C clutch circuit (if equipped).
3. This step checks for a good ground to terminal PB5 (non-A/C equipped vehicles only).

A Tech 1 scan tool has the ability to command the cooling fan and A/C clutch relays ON and OFF.

A faulty connections, or an open circuits 335, 459 or 451 can result in a DTC 28.

Note. Refer to WIRING DIAGRAMS for circuit schematic.

DTC 28 Diagnostic Flow Chart. Scheme 23

CODE 29, QUAD-DRIVER 3

PCM controls most components with electronic switches completing a ground circuit when actuated. Switches are arranged in groups of 4, called Quad-Driver Modules (QDMs), which can independently control up to 4 outputs (control module terminals). When an output is actuated, terminal is grounded and its voltage normally will be low. When an output is off, its terminal voltage will normally be high.

QDMs are fault-protected. If a relay or solenoid coil is shorted (having very low resistance) or if control side of circuit is shorted to voltage, too much current would be allowed into QDM. QDM senses this and turns driver off or QDM's internal resistance increases to limit current flow and protect QDM. Result is high output terminal voltage when it should be low. If circuit from battery voltage or component is open or control side of circuit is shorted to ground, terminal voltage will be low, even when output is turned off. Either of these conditions is considered to be a QDM fault.

Each QDM has a separate fault line to indicate presence of a current fault to control module central processor. A scan tester displays status of each of these fault lines as "low equals okay" or "high equals fault". Code 29 will set if QDM No. 2 is high for 20 seconds or more with battery voltage sensed at greater than 10.5 volts.

Note. Test numbers refer to numbers on diagnostic chart.

1. Checks if PCM is grounding shift solenoids "A" and "B".
2. Checks to see if Tech 1 can command shift solenoids.
3. Checks for short to voltage on shift solenoid circuits.
4. Checks continuity of shift solenoid circuits.
5. Checks to see if PCM is grounding TCC PWM.
6. Checks to see if PCM can command TCC PWM.

Tech 1 has the ability to command shift solenoids and TCC PWM on and off. A faulty connection or an open circuit can result in setting Code 29. Inspect harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, poor terminal-to-wire connections or damaged harness.

Perform intermittent check by monitoring circuit and code status while wiggling related wiring and connectors. If failure is induced, monitored circuit status will change rapidly and/or related code will set.

Code 29 Schematic (2.3L) Quad-Driver 3. Scheme 24

Code 29 Diagnostic Flow Chart - 1 Of 2 (2.3L) Quad-Driver 3. Scheme 25

Code 29 Diagnostic Flow Chart - 2 Of 2 (2.3L) Quad-Driver 3. Scheme 26

CODE 31, PRNDL ERROR

Transmission range switch is mounted on the transaxle assembly. Code will set if PCM recognizes an invalid PRNDL condition, vehicle speed is greater than 5 MPH and conditions have existed for 5 seconds or more.

Note. Test numbers refer to numbers on diagnostic chart.

1. Checks for proper operation of transmission range switch.
2. Checks for an open or grounded circuit.

When fault is present, PCM assumes the D3 position until a correct combination is received by PCM. Until then, some gear select positions may not be possible until fault is cleared (repaired). Inspect harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, poor terminal-to-wire connections or damaged harness.

Perform intermittent check by monitoring circuit and code status while wiggling related wiring and connectors. If failure is induced, monitored circuit status will change rapidly and/or related code will set.

Code 31 Schematic, PRNDL Error (2.3L). Scheme 27

Code 31 Diagnostic Flow Chart, PRNDL Error (2.3L). Scheme 28

CODE 33, MAP SENSOR SIGNAL VOLTAGE HIGH

Code 33 will set when MAP signal voltage reading is high for greater than a precalibrated period of time, TPS voltage indicates throttle is closed and neither Code 21 nor 22 is present. Most likely causes for code are: open sensor ground circuit, sensor signal circuit shorted to voltage, faulty MAP sensor, MAP sensor vacuum leak or faulty PCM.

Note. Test numbers refer to numbers on diagnostic chart.

1. This test confirms Code 33 and determines if it is result of a hard failure or an intermittent condition.
2. This step simulates conditions for a Code 34. If control module recognizes and sets Code 34, low MAP signal, control module and 5-volt reference and MAP signal circuits are not at fault. If ground circuit is shared with other sensors and ground circuit becomes open, additional codes related to these sensors may be set.

With ignition switch in ON position and engine stopped, manifold pressure is equal to atmospheric pressure and signal voltage will be high. Comparison of BARO readings from a known good vehicle using same sensor is a good way to check accuracy of suspect sensor. Readings should be same within .4 volt. Code 33 will result if ground circuit is open, MAP signal circuit is shorted to voltage or to 5-volt reference circuit.

CODE 33 PCM TERMINAL & CIRCUIT WIRING IDENTIFICATION

1. For shared sensor reference and shared sensor ground tie-offs, see appropriate wiring diagram in WIRING DIAGRAMS section.

Code 33 Schematic (2.3L) MAP Sensor Signal Voltage High. Scheme 29

Code 33 Diagnostic Flow Chart (2.3L) MAP Sensor Signal Voltage High. Scheme 30

CODE 34, MAP SENSOR SIGNAL VOLTAGE LOW

Code 34 will set when ignition is on, throttle is off idle, no TP sensor code exists and MAP signal voltage is lower than expected for off idle engine operation. Most likely causes for code are: MAP sensor signal circuit open or shorted to ground, 5-volt reference circuit open or shorted to ground, faulty sensor connection, faulty sensor or faulty PCM.

Note. Test numbers refer to numbers on diagnostic chart.

1. This confirms conditions for Code 34 and determines if code was caused by a hard failure or an intermittent fault.
2. Jumpering MAP signal to 5-volt reference at MAP harness connector will determine if sensor is at fault or if a problem exists with control module or wiring.
3. Scan tester may not display 12 volts. Control module recognizes voltage as greater than 4 volts (high MAP voltage signal), indicating control module and MAP signal circuit are not at fault.

With ignition switch in ON position and engine stopped, manifold pressure is equal to atmospheric pressure and signal voltage will be high. Comparing BARO readings with a known good vehicle using same sensor is a good way to check accuracy of suspect sensor.

Readings should be same within .4 volt. A Code 34 will also result if 5-volt reference and MAP signal circuits are open or shorted to ground.

CODE 34 PCM TERMINAL & CIRCUIT WIRING IDENTIFICATION

1. For shared sensor reference and shared sensor ground tie-offs, see appropriate wiring diagram in WIRING DIAGRAMS section.

Code 34 Diagnostic Flow Chart (2.3L) MAP Sensor Signal Voltage Low. Scheme 31

CODE 35, IAC IDLE SPEED ERROR

Code 35 will set when closed throttle engine speed is 150-200 RPM greater or less than desired idle speed, IAC is attempting to adjust idle speed (high or low IAC counts) and conditions have been present for a precalibrated period of time.

Note. Test numbers refer to numbers on diagnostic chart.

1. Tech 1 RPM control mode is used to extend and retract IAC valve. Movement is verified by an engine speed change. If no change in speed occurs, valve can be retested when removed from throttle body. If IAC valve is retracted beyond control range (about 1500 RPM), many flashes in extend position may occur before engine speed begins to drop. This is normal on certain engines. Fully extending IAC may cause engine to stall. This may be normal.
2. This test uses Tech 1 to command IAC-controlled idle speed. Control module issues commands to obtain requested idle speed. Each light on node light should flash Red and Green while IAC valve is cycled. While sequence of color is not important, check circuits for faults beginning with poor terminal contacts if either light is off or does not flash Red and Green.

A slow, unstable idle may be caused by a system problem which cannot be overcome by IAC. Scan counts will be greater than 60 if idle is too low and zero counts if idle is too high. If idle is too high, stop engine. Fully extend IAC with driver. Start engine. If idle speed is greater than 800 RPM, look for possible vacuum leaks.

System Too Lean

If air/fuel ratio is too lean, idle speed may be either too high (check for vacuum leaks) or too low. Engine speed may vary up and down; disconnecting IAC may not help. Scan and/or digital voltmeter (10-megohm) will read an oxygen (O2) sensor output less than 300 mV (.3 volt). Check for low fuel pressure or water in fuel. A contaminated O2 sensor (caused by silicone) will produce lean air/fuel mixtures with an O2 sensor output fixed greater than 800 mV (.8 volt). This may also set Code 45.

System Too Rich

If air/fuel ratio is too rich, idle speed will be too low and scan tester counts will usually be greater than 80. System may be obviously rich, with Black smoke from exhaust pipe. Scan tester and/or voltmeter will read an O2 sensor voltage signal fixed greater than 800 mV (.8 volt). Look for high fuel pressure and injectors leaking or sticking. Remove IAC, and inspect bore for foreign material and evidence of IAC valve dragging bore.

Throttle Body

Remove IAC, and inspect bore for evidence of IAC valve dragging.

IAC Valve Connections

Inspect carefully for loose or corroded connections.

PCV Valve

An incorrect PCV valve may cause incorrect idle speed.

Code 35 Schematic (2.3L) IAC Idle Speed Error. Scheme 32

Code 35 Diagnostic Flow Chart (2.3L) IAC Idle Speed Error. Scheme 33

CODE 43, KNOCK SENSOR ERROR

Note. Test numbers refer to numbers on diagnostic chart.

1. If conditions for code exist, SERVICE ENGINE SOON light will be on.
2. If engine has an internal problem, sensor may be responding to mechanical noise.
3. Checks knock sensor activity. Scan displays knock sensor activity in counts (about 35-50 at idle). Counts should rise as engine speed increases.
4. Checks internal resistance of knock sensor.
5. Checks knock sensor connections. A faulty connection or component will set a Code 43

Inspect harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, poor terminal-to-wire connections or damaged harness. Perform intermittent check by monitoring circuit and code status while wiggling related wiring and connectors. If failure is induced, monitored circuit status will change rapidly and/or related code will set.

Code 43 Schematic (2.3L) Knock Sensor Error. Scheme 34

Code 43 Diagnostic Flow Chart (2.3L) Knock Sensor Error. Scheme 35

CODE 44, LEAN EXHAUST INDICATION

Note. Some models are equipped with 2 oxygen sensors. On these models, Code 44 will set if the left sensor circuit is lean. Code 64 will set if the right sensor circuit is lean. Use this chart for Code 64 also and perform tests for applicable sensor.

O2 sensor acts like an open sensor circuit and produces no voltage when exhaust temperature is less than 600°F (316°C). An open sensor circuit or cold sensor causes "open loop" operation. On models with 2 oxygen sensors, Code 44 will reflect a lean left O2 sensor; Code 64 will indicate a lean right O2 sensor. Perform test procedures for right or left sensor as necessary.

Code is set when O2 sensor voltage signal at control module is low (less than 0.3 volt) for a precalibrated period and fuel system is operating in "closed loop" and attempting to richen mixture. Most likely causes for setting of code are: an actual lean condition, a short to ground on sensor signal circuit or a faulty PCM.

Note. Test number refers to number on diagnostic chart.

1. Checks to see if O2 sensor is registering a lean condition.

Using scan tester, observe Block Learn Memory (BLM) value at different RPMs. If conditions for a lean exhaust code exist, block learn value will be about 150.

O2 Sensor Wire

O2 sensor wire may be mispositioned and laying against exhaust manifold. Check for ground between sensor and wire connector.

Fuel Contamination

Water, even small amounts, near in-tank fuel pump inlet can be delivered to injector. Water may cause a lean exhaust, setting code.

Fuel Pressure

System will be lean if fuel pressure is low. If necessary, monitor fuel pressure while driving vehicle. For fuel pressure checking procedure, see BASIC TESTING article in this section.

Exhaust Leaks

If exhaust system has large leaks, exhaust system negative pressure pulses can cause outside air to be drawn into system and past O2 sensor. Vacuum or crankcase leaks can also cause a lean condition.

Misfire Or Stall

If engine misfires or stalls (including running out of fuel) while vehicle is moving, code may set. If code is intermittent, see INTERMITTENTS in TESTS W/O CODES article in this section.

CODE 44 PCM TERMINAL & CIRCUIT WIRING IDENTIFICATION

Code 44 Diagnostic Flow Chart (2.3L) Lean Exhaust Indication. Scheme 36

CODE 45, RICH EXHAUST INDICATION

Note. Some models are equipped with 2 oxygen sensors. On these models, Code 45 will set if the left sensor circuit is rich. Code 65 will set if the right sensor circuit is lean. Use this chart for Code 65 also and perform tests for applicable sensor.

O2 sensor acts like an open sensor circuit and produces no voltage when exhaust temperature is less than 600°F (316°C). An open sensor circuit or cold sensor causes "open loop" operation. Code 45 indicates a rich exhaust. Diagnosis should begin with fuel pressure, leaking injector, ignition shielding (ground), vapor canister fuel saturation, coolant sensor, MAP sensor, O2 sensor contamination and TPS intermittent output.

Code is set when fuel system is operating in "closed loop", throttle angle is greater than idle, O2 sensor signal at control module is greater than .7 volt for a precalibrated period, fuel system is attempting to lean mixture and time since engine start is one minute or more. Most likely causes of code are: an actual rich condition, a short to voltage on sensor signal circuit or a faulty PCM.

Note. Test number refers to number on diagnostic chart.

1. Test checks to see if O2 sensor is registering a rich condition.

If other codes of lower number are set with code, use those charts first. Malfunction in MAP or TPS sensor circuits can cause a rich exhaust code to set. If other codes are not set, rich exhaust is most likely caused by

Fuel Pressure High

If fuel pressure is too high, air/fuel ratio will be rich. For fuel pressure checking procedure, see BASIC TESTING article in this section. Control module can compensate for slight increases, but a code will be set if air/fuel ratio becomes too rich.

Ignition Ground

If an open occurs on HEI ground circuit, HEI induced electrical "noise" may result, causing simulated reference pulses to be picked up by control module on reference line of EST harness. Additional pulses result in a higher than actual engine speed signal. Control module will increase injector pulse width ("on" time) to match increased RPM signal. Scan tester will show higher than actual RPM, which can help in diagnosing this problem.

Evaporative Fuel Canister

Fuel saturation of charcoal canister will cause a rich air/fuel ratio. If canister is full of fuel, check canister control valves and hoses.

MAP Sensor

An output causing control module to sense a higher than normal manifold pressure (low vacuum) can cause system to go rich. Disconnecting MAP sensor will allow control module to substitute a fixed value for MAP sensor. If condition disappears, substitute a different MAP sensor, and continue testing.

TPS

An intermittent TPS output will cause system to operate rich due to a false indication of engine acceleration.

O2 Sensor Contamination

O2 sensor contamination, caused by silicone in certain fuels or use of improper RTV sealant, may cause a White powdery coating to cover exterior of O2 sensor. False high signal voltage (low oxygen content sensed) produced is interpreted by control module as a rich mixture, causing control module to set code.

EGR Problem

EGR valve sticking open at idle is usually accompanied by a rough idle and/or stalling. Also check for shorted/leaking injector and fuel-contaminated oil. If code is intermittent, see INTERMITTENTS in TESTS W/O CODES article in this section.

CODE 45 PCM TERMINAL & CIRCUIT WIRING IDENTIFICATION

Code 45 Diagnostic Flow Chart (2.3L) Rich Exhaust Indication. Scheme 37

CODE 51, FAULTY PROM/MEM-CAL

Ensure all pins are fully inserted in socket. If pins are okay, replace PROM/MEM-CAL, clear memory and recheck. If code reappears, replace control module.

CODE 52, FAULTY CAL-PAK

Ensure all pins are fully inserted in socket. If pins are okay, replace CAL-PAK, clear memory and recheck. If Code 51 reappears, replace control module.

CODE 53, SYSTEM VOLTAGE HIGH

This code indicates a basic charging system problem. Code 53 will set when voltage at control module terminal is greater than specification for a precalibrated time. If voltage at PCM battery voltage terminal is not within specification, check and repair charging system.

CHARGING SYSTEM SPECIFICATIONS

Code 53 Schematic (2.3L) System Voltage High. Scheme 38

Code 53 Diagnostic Flow Chart (2.3L) System Voltage High. Scheme 39

CODE 55, PCM ERROR

Ensure PCM grounds are okay. Ensure correct EPROM is being used and that it is properly installed. If okay, replace PCM. Clear codes, confirm closed loop operation and check operation of Malfunction Indicator Light (MIL).

CODE 55, FUEL LEAN MONITOR

PCM is capable of determining if fuel system can deliver adequate fuel during power enrichment (heavy acceleration). During power enrichment conditions, PCM expects to see both O2 sensors registering rich. If both sensors do not register rich, Code 55 will set.

Low fuel pressure or restricted fuel flow may cause a lean condition. Check for plugged injectors, poor or contaminated fuel, low fuel level and restricted fuel supply. Vapor lock can also cause Code 55.

Code 55 Schematic (2.3L) Fuel Lean Monitor. Scheme 40

CODE 65, INJECTOR CURRENT LOW

PCM has 2 injector driver circuits, each controlling a pair of injectors (1 and 4, or 2 and 3). PCM monitors current of each injector driver circuit by measuring voltage drop through a fixed resistor. PCM is able to control voltage drop. Current through each driver is allowed to rise to peak of 4 amps, enabling injectors to open quickly; current is then reduced to one amp, holding injectors open. This is called "peak and hold". If current cannot reach a 4-amp peak, Code 65 is set.

This code is also set if

1. 4-amp injector current was not reached on each circuit.
2. Battery voltage greater than 9 volts.
3. Injectors pulsed on longer than calibrated pulse width.
4. Conditions met for 20 seconds. NOTE: Test numbers refer to numbers on diagnostic chart.

1. Determines if conditions for code are hard or intermittent.
2. Checks PCM and harness wiring to 3-terminal injector harness connector.
3. This tests for open injector harness or injector.
4. Results of step 2) will determine which branch to follow on Code 65 (2 of 2) flow chart.
5. Each harness was confirmed as being okay in step 2). This test will check remainder of circuit from injectors to PCM.
6. This checks for short to voltage in injector driver circuits.
7. Determines if injector driver circuits are shorted to ground.

Note. Although shorted harness or injector (zero ohms) will not set a Code 65, problem should be corrected if discovered.

An open in injector drive or "peak and hold" circuits or PCM drive circuits shorted to voltage will cause a Code 65 to be set and also cause misfire due to an inoperative pair of injectors. "Peak and hold" circuits shorted to ground will cause a Code 65 to set while allowing injectors to pulse. An intermittent problem would have to be present for at least 20 seconds to set Code 65.

Code 65 Schematic (2.3L) Injector Current Low. Scheme 41

Code 65 Diagnostic Flow Chart - 1 Of 2 (2.3L) Injector Current Low. Scheme 42

Code 65 Diagnostic Flow Chart - 2 Of 2 (2.3L) Injector Current Low. Scheme 43

CODE 66, A/C PRESSURE SENSOR

A/C pressure sensor responds to changes in A/C refrigerant system high side pressure. PCM uses A/C compressor load input to determine engine idle speed. Sensor uses a 5-volt reference signal from PCM and returns an input signal to PCM on a separate line. Low pressure (zero psi) will return a signal of about .1 volt. High pressure will return a signal of about 4.9 volts. The PCM will disable the compressor clutch if Code 66 is current.

Note. Test numbers refer to numbers on diagnostic chart.

1. Checks voltage signal from A/C pressure sensor to PCM.
2. Checks to see if high signal is from a shorted sensor or a short to voltage in circuit. Normally, disconnecting sensor would make a normal circuit go to nearly zero volts.
3. Checks to see if low voltage signal is from sensor or circuit. Jumpering sensor signal circuit to 5-volt reference checks circuit, connections and PCM.
4. Checks to see if low voltage signal was due to an open in sensor circuit or 5-volt reference circuit; previous step eliminated pressure sensor as a possible cause.

The 5-volt reference for the TPS is the same 5 volts used by the A/C pressure sensor. If the 5-volt reference has a short to ground, the MAP sensor, A/C pressure sensor and other related sensors will also have a short to ground. This short to ground will not damage the PCM. When the shorted 5-volt reference circuit is repaired, the PCM 5-volt reference will return to normal.

In extremely low temperature climate, the A/C pressure signal can drop as low as .3 volt. If this happens, Code 66 will set and disable the A/C system. Clear code and recheck A/C system in a heated garage to determine if outside ambient temperature is cause for Code 66 setting.

Code 66 Schematic (2.3L) A/C Pressure Sensor. Scheme 44

Code 66 Diagnostic Flow Chart (2.3L) A/C Pressure Sensor. Scheme 45

SUMMARY

If no hard fault codes are present, driveability symptoms exist or intermittent codes exist, proceed to TESTS W/O CODES article in this section for diagnosis by symptom (i.e., ROUGH IDLE, NO START, etc.) or intermittent diagnostic procedures.

2.3L (VIN D) PCM Wiring Diagram (1 Of 3). Scheme 46

2.3L (VIN D) PCM Wiring Diagram (2 Of 3). Scheme 47

2.3L (VIN D) PCM Wiring Diagram (3 Of 3). Scheme 48

See also:
• BASIC TESTING
• TESTS W/O CODES
• SYSTEM/COMPONENT TESTS - 2.3L
• HARD OR INTERMITTENT TROUBLE CODE DETERMINATION
• DATA LINK CONNECTOR (DLC) TEST TERMINALS
• SCAN TESTER USAGE
• SCAN DATA
• CODE 13
• CODE 14
• CODE 15
• CODE 19
• CODE 21
• CODE 22
• CODE 23
• CODE 24
• CODE 25
• CODE 26
• CODE 27
• CODE 28
• CODE 29
• CODE 31
• CODE 33
• CODE 34
• CODE 35
• CODE 43
• CODE 44
• CODE 45
• CODE 51
• CODE 52
• CODE 53
• CODE 55
• CODE 55
• CODE 65
• CODE 66
• CLEARING TROUBLE CODES