Engine Controls - Tests W/codes - 5.2l Jeep Grand Cherokee ZJ

INTRODUCTION

If no faults were found while performing BASIC DIAGNOSTIC PROCEDURES, proceed with self-diagnostics. If no trouble codes or if only pass codes are present after entering self-diagnostics, proceed to TEST NTC-1A procedures in this article or refer to basic tests in the TESTS W/O CODES article in this section for diagnosis by symptom (i.e., ROUGH IDLE, NO START, etc.).

MODEL IDENTIFICATION

Vehicle body codes are used throughout self-diagnostic tests. See VEHICLE BODY IDENTIFICATION table for model identification.

VEHICLE BODY IDENTIFICATION

SELF-DIAGNOSTIC SYSTEM

SYSTEM DIAGNOSTICS

Note. Malfunction Indicator Light (MIL) may also be referred to as CHECK ENGINE Light.

Self-diagnostic capabilities of this system, if properly used, can simplify testing. Powertrain Control Module (PCM) monitors several different engine control system circuits.

If a problem is sensed with a monitored circuit, PCM memory stores a trouble code, MIL glows and PCM enters limp-in mode. In limp-in mode, PCM compensates for component failure by substituting information from other sources. This allows vehicle operation until repairs can be made.

Test circuits and repair or replace components as required. If problem is repaired or ceases to exist, PCM cancels trouble code after 50 ignition on/off cycles.

A specific trouble code results from a particular system failure. A trouble code does not condemn a specific component; component is not necessarily reason for failure. Trouble codes only suggest probable malfunction area.

Hard Failures

Hard failures cause MIL to glow and remain on until malfunction is repaired. If light comes on and remains on (light may flash) during vehicle operation, determine cause of malfunction using self-diagnostic tests. If a sensor fails, PCM will use a substitute value in its calculations, allowing engine to operate in limp-in mode. In this condition, vehicle will run, but driveability may be poor.

Intermittent Failures

Intermittent failures may cause MIL to flicker or stay on until intermittent trouble code goes away. However, PCM memory will retain corresponding trouble code. If related trouble code does not reoccur within a certain time frame, related trouble code will be erased from PCM memory. Intermittent failures can be caused by a failed sensor, bad connector or wiring related problems.

SERVICE PRECAUTIONS

During diagnosis, following these precautions

1. Always relieve fuel pressure before disconnecting any fuel injection-related component. DO NOT allow fuel to contact engine or electrical components. See FUEL PRESSURE RELEASE.
2. When battery is disconnected, vehicle computer and memory systems may lose memory data. Driveability problems may exist until computer systems have completed a relearn cycle. See «COMPUTER RELEARN PROCEDURES»(/jeep/grand-cherokee/zj-1992-1996/remont/computer-relearn/#computer-relearn-procedures) article in GENERAL INFORMATION section before disconnecting battery.
3. Vehicle must have a fully charged battery and functional charging system.
4. Probe PCM 60-pin connector from pin side. DO NOT backprobe PCM connector.
5. DO NOT cause short circuits when performing electrical tests. This will set additional trouble codes, making diagnosis of original problem more difficult.
6. DO NOT use a test light instead of a voltmeter.
7. When checking for spark, ensure coil wire is no more than 1/4" from ground. If coil wire is more than 1/4" from ground, damage to vehicle electronics and/or PCM may result.
8. DO NOT prolong testing of fuel injectors, or engine may hydrostatically (liquid) lock.
9. Always repair lowest trouble code number (CHECK ENGINE light) or first trouble code displayed (DRB) first.
10. Always perform verification procedure test after repairs are made.
11. Always disconnect DRB after use.
12. Always disconnect DRB before charging battery.

VISUAL INSPECTION

Most driveability problems in engine control system result from failed wiring, poor electrical connections or leaking air and vacuum hose connections. To avoid unnecessary component testing, perform a visual inspection before beginning self-diagnostic tests.

DIAGNOSTIC PROCEDURE

Note. DO NOT skip any steps in self-diagnostic tests, or incorrect diagnosis may result.

Always perform a visual inspection before attempting to diagnose engine control system problems. See VISUAL INSPECTION . Enter on-board diagnostics, and retrieve trouble codes. See ENTERING ON-BOARD DIAGNOSTICS . If trouble codes are not present and/or using Diagnostic Readout Box (DRB), proceed to one of following tests.

1. Go to appropriate «TEST NS-1A»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ns-1a-qualifying-no-start-condition) if a no-start condition exists or engine stalls after start-up. Perform indicated VERIFICATION TEST after repairs have been made.
2. Go to appropriate TEST TC-1A if engine runs but has performance problems. Perform indicated VERIFICATION TEST after repairs have been made.
3. Go to appropriate «TEST NTC-1A»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l) if a driveability problem exits but no trouble codes are present. Perform indicated VERIFICATION TEST after repairs have been made.

ENTERING ON-BOARD DIAGNOSTICS

Note. Although other scan testers are available, manufacturer recommends using Diagnostic Readout Box (DRB). MIL function can be used but has limited diagnostic capability.

DRB Diagnostic Mode

1. Turn ignition off. Connect DRB to data link connector. Data link connector is located in engine compartment, near PCM.
2. Start engine (if possible). With foot on brake, move transmission shift lever through all positions, ending in Park (A/T). Turn A/C switch on and then off (if equipped).
3. Turn engine off. Without starting engine again, turn ignition on. Enter selection No. 1, STAND ALONE DRB-III. Enter selection No. 1, CHRYSLER DOMESTIC. Enter selection No. 1, ENGINE. Proceed until READ DTCS selection is offered. After trouble codes have been accessed, refer to the appropriate «TEST NS-1A»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ns-1a-qualifying-no-start-condition) (NO-START TEST-1A) or «TEST TC-1A»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-tc-1a-checking-system-for) (TROUBLE CODE TEST-1A) to diagnose problem.
4. To erase trouble codes while in this mode, press BACK key. At DRB display, scroll to YES - ERASE FAULTS. A confirmation message should then appear, FAULTS ERASED.

MIL Diagnostic Mode

1. Start engine (if possible). Move transmission shift lever through all positions, ending in Park. Turn A/C on, then off (if equipped).
2. Turn engine off. Without starting engine again, turn ignition on, off, on, off and on within 5 seconds. Record 2-digit trouble codes as displayed by flashing MIL.
3. For example, trouble code 23 is displayed as flash, flash, 4-second pause, flash, flash, flash. After a slightly longer pause, other codes stored are displayed in numerical order. When MIL begins to flash trouble codes, it cannot be stopped. Start over if count is lost. Code 55 indicates end of trouble code display.
4. Refer to «TROUBLE CODES/MESSAGES»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__trouble-codesmessages) to translate trouble code number to a DRB trouble code. Once trouble area is identified, refer to TEST TC-1A. Use DRB trouble codes to find appropriate test.
5. As an example, a 2.5L engine starts and runs but has a driveability problem. MIL indicates a Code 14. Refer to «TROUBLE CODES/MESSAGES»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__trouble-codesmessages) to translate trouble code number to a DRB trouble code. When DRB trouble code is obtained, refer to appropriate test in this article. To clear trouble codes, see «CLEARING TROUBLE CODES»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__clearing-trouble-codes) .

CLEARING TROUBLE CODES

Note. Trouble codes can also be cleared using DRB. See DRB DIAGNOSTIC MODE under ENTERING ON-BOARD DIAGNOSTICS .

Trouble codes are cleared by disconnecting negative battery cable for at least 15 seconds, allowing PCM to clear trouble codes.

INACTIVE TROUBLE CODE CONDITION

This procedure applies if you have been sent here from diagnostic tests and have just attempted to simulate condition that initially set trouble code. Following additional checks may assist in identifying a possible intermittent problem

1. Visually inspect related wiring harness connectors for broken, bent, pushed-out or corroded terminals.
2. Visually inspect related wiring harnesses for chafed, pierced or partially broken wires.
3. Check all pertinent Technical Service Bulletins (TSBs).

FUEL PRESSURE RELEASE

Disconnect negative battery cable. Loosen fuel filler cap to release tank pressure. Remove protective cap from pressure test port on fuel rail. Using appropriate fuel pressure gauge/hose with gauge removed, place gauge end of hose into approved gasoline container. To release pressure, screw other end of hose onto pressure test port. After pressure is released, remove hose from test port and install protective cap.

Scheme 17

Scheme 18

TROUBLE CODES/MESSAGES

Note. Not all trouble codes apply to all vehicles. Some trouble codes have more than one meaning. When a trouble code has more than one meaning, MIL is unable to distinguish between different failures.

Code 11

DRB displays NO CRANK REFERENCE SIGNAL AT PCM. Condition is: no crankshaft reference signal detected during cranking.

Code 12

DRB displays BATTERY DISCONNECT. Condition is: Direct battery input to Powertrain Control Module (PCM) disconnected within last 50 key-on cycles.

Code 13

DRB displays SLOW CHANGE IN IDLE MAP SENSOR SIGNAL. Condition is: Manifold Absolute Pressure (MAP) sensor output change slower and/or smaller than expected.

DRB displays NO CHANGE IN MAP FROM START TO RUN. Condition is: no difference recognized between Manifold Absolute Pressure (MAP) reading and barometric (atmospheric) pressure reading at start-up.

Code 14

DRB displays MAP VOLTAGE TOO LOW. Condition is: Manifold Absolute Pressure (MAP) sensor input less than minimum acceptable voltage.

DRB displays MAP VOLTAGE TOO HIGH. Condition is: Manifold Absolute Pressure (MAP) sensor input more than maximum acceptable voltage.

Code 15

DRB displays NO VEHICLE SPEED SENSOR SIGNAL. Condition is: no Vehicle Speed Sensor (VSS) signal detected with road load conditions.

Code 17

DRB displays ENGINE IS COLD TOO LONG. Condition is: coolant temperature stays less than normal operating temperature during vehicle operation.

Code 21

DRB displays O2S STAYS AT CENTER. Condition is: no rich or lean signal detected from oxygen sensor input.

DRB displays O2S SHORTED TO VOLTAGE. Condition is: oxygen sensor input voltage maintained at more than normal operating range.

Code 22

DRB displays ECT SENSOR VOLTAGE TOO LOW. Condition is: Engine Coolant Temperature (ECT) sensor input less than minimum acceptable voltage.

DRB displays ECT SENSOR VOLTAGE TOO HIGH. Condition is: Engine Coolant Temperature (ECT) sensor input more than maximum acceptable voltage.

Code 23

DRB displays INTAKE AIR TEMPERATURE SENSOR VOLTAGE LOW. Condition is: Intake Air Temperature (IAT) sensor input less than minimum acceptable voltage.

DRB displays INTAKE AIR TEMPERATURE SENSOR VOLTAGE HIGH. Condition is: Intake Air Temperature (IAT) sensor input more than maximum acceptable voltage.

DRB displays THROTTLE BODY TEMP VOLTAGE HIGH. Condition is: throttle body temperature input is more than maximum acceptable voltage.

DRB displays THROTTLE BODY TEMP VOLTAGE LOW. Condition is: throttle body temperature input is less than maximum acceptable voltage.

Code 24

DRB displays THROTTLE POSITION SENSOR VOLTAGE LOW. Condition is: Throttle Position Sensor (TPS) input less than minimum acceptable voltage.

DRB displays THROTTLE POSITION SENSOR VOLTAGE HIGH. Condition is: Throttle Position Sensor (TPS) input more than maximum acceptable voltage.

Code 25

DRB displays IDLE AIR CONTROL MOTOR CIRCUITS. Condition is: open or shorted condition detected in one or more Idle Air Control (IAC) motor circuits.

Code 27

DRB displays INJECTOR (#1-#8) CONTROL CIRCUIT. Condition is: injector output driver does not respond properly to Powertrain Control Module (PCM) control signal.

Code 31

DRB displays EVAP PURGE SOLENOID CIRCUIT. Condition is: open or shorted condition detected in purge solenoid circuit.

Code 32

DRB displays EGR SOLENOID CIRCUIT. Condition is: open or shorted condition detected in EGR solenoid circuit.

DRB displays EGR SYSTEM FAILURE. Condition is: required change in air/fuel ratio not detected during diagnostic test. Trouble code is only present on models with California emissions packages.

Code 33

DRB displays A/C CLUTCH RELAY CIRCUIT. Condition is: open or shorted condition detected in A/C clutch relay circuit.

Code 34

DRB displays SPEED CONTROL SOLENOID CIRCUITS. Condition is: open or shorted condition detected in speed control vacuum or vent solenoid circuits.

DRB displays SPEED CONTROL SWITCH ALWAYS LOW. Condition is: speed control switch input less than minimum acceptable level.

DRB displays SPEED CONTROL SWITCH ALWAYS HIGH. Condition is: speed control switch input more than minimum acceptable level.

Code 35

DRB displays RADIATOR FAN RELAY CIRCUIT. Condition is: open or shorted condition detected in radiator fan relay circuit.

Code 37

DRB displays TORQUE CONVERTER CLUTCH SOLENOID CIRCUIT. Condition is: open or shorted condition detected in torque converter clutch solenoid circuit.

DRB displays TRANS TEMP SENSOR VOLTAGE TOO LOW. Condition is: voltage low at transmission temperature sensor.

DRB displays TRANS TEMP SENSOR VOLTAGE TOO HIGH. Condition is: voltage high at transmission temperature sensor.

Code 41

DRB displays GENERATOR FIELD NOT SWITCHING PROPERLY. Condition is: open or shorted condition detected in alternator field circuit.

Code 42

DRB displays AUTO SHUTDOWN RELAY CONTROL CIRCUIT. Condition is: open or shorted condition detected in Auto Shutdown (ASD) relay circuit.

DRB displays NO ASD RELAY VOLTAGE SENSE AT PCM. Condition is: Powertrain Control Module (PCM) did not receive message in Auto Shutdown (ASD) relay circuit.

Code 43

DRB displays IGNITION COIL (#1-#5) PRIMARY CIRCUIT. Condition is: peak primary circuit current not achieved with maximum dwell time.

Code 44

DRB displays BATTERY TEMP SENSOR VOLTS OUT OF LIMIT. Condition is: battery temperature sensor volts out of limit.

Code 45

DRB displays OVERDRIVE SOLENOID. Condition is: open or shorted condition detected in overdrive solenoid circuit.

Code 46

DRB displays CHARGING SYSTEM VOLTAGE TOO HIGH. Condition is: battery voltage sense input more than target charging voltage during engine operation.

Code 47

DRB displays CHARGING SYSTEM VOLTAGE TOO LOW. Condition is: battery voltage sense input less than target charging voltage during engine operation.

Code 51

DRB displays O2S STAYS BELOW CENTER (LEAN). Condition is: oxygen sensor input indicates lean air/fuel ratio during engine operation.

Code 52

DRB displays ADDITIVE ADAPTIVE MEMORY AT LEAN LIMIT. Condition is: additive adaptive memory at lean limit.

DRB displays O2S STAYS ABOVE CENTER (RICH). Condition is: oxygen sensor input indicates rich air/fuel ratio during engine operation.

Code 53

DRB displays INTERNAL PCM FAILURE. Condition is: Powertrain Control Module (PCM) detects internal failure.

DRB displays PCM FAILURE SPI COMMUNICATION. Condition is: Powertrain Control Module (PCM) detects internal failure.

Code 54

DRB displays CRANKSHAFT SIGNAL SYNC PICK-UP SIGNAL. Condition is: no fuel sync signal detected during crankshaft rotation.

DRB displays NO CAM SYNC SIGNAL AT PCM. Condition is: open or shorted condition detected in cam sync signal circuit.

Code 55

DRB display will be blank. Completion of trouble code display by MIL light.

Code 62

DRB displays PCM FAILURE SRI MILES NOT STORED. Condition is: Powertrain Control Module (PCM) detects internal failure.

Code 63

DRB displays PCM FAILURE EEPROM WRITE DENIED. Condition is: unsuccessful attempt to write to an EEPROM location by PCM.

CONNECTOR IDENTIFICATION

CONNECTOR IDENTIFICATION

A/C CLUTCH RELAY CONNECTOR TERMINAL IDENTIFICATION

Scheme 19

ASD RELAY CONNECTOR TERMINAL IDENTIFICATION

Scheme 20

CAMSHAFT POSITION SENSOR CONNECTOR TERMINAL ID

Scheme 21

CRANKSHAFT POSITION SENSOR CONNECTOR TERMINAL IDENTIFICATION

Scheme 22

EGR SOLENOID CONNECTOR TERMINAL IDENTIFICATION

Scheme 23

ECT SENSOR CONNECTOR TERMINAL IDENTIFICATION

Scheme 24

EVAPORATIVE PURGE SOLENOID CONNECTOR TERMINAL ID

Scheme 25

FUEL PUMP CONNECTOR TERMINAL IDENTIFICATION

Scheme 26

FUEL PUMP CONNECTOR TERMINAL IDENTIFICATION

Scheme 27

FUEL PUMP RELAY CONNECTOR TERMINAL IDENTIFICATION

Scheme 28

IAC MOTOR CONNECTOR TERMINAL IDENTIFICATION

Scheme 29

IAT SENSOR CONNECTOR TERMINAL ID

Scheme 30

MAP SENSOR CONNECTOR TERMINAL ID

Scheme 31

OVERDRIVE SOLENOID CONNECTOR TERMINAL IDENTIFICATION

Scheme 32

OXYGEN SENSOR CONNECTOR TERMINAL IDENTIFICATION

Scheme 33

O2 SENSOR CONNECTOR TERMINAL ID

TCC RELAY CONNECTOR TERMINAL IDENTIFICATION

Scheme 34

TRANSMISSION SOLENOID CONNECTOR TERMINAL ID

Scheme 35

TRANSMISSION TEMPERATURE SENSOR CONNECTOR TERMINAL ID

Scheme 36

Scheme 37

SELF-DIAGNOSTIC TESTS

Note. In following self-diagnostic tests, illustrations are courtesy of Chrysler Corp.

TEST TC-1A - CHECKING SYSTEM FOR TROUBLE CODES

Note. For connector terminal identification, see CONNECTOR IDENTIFICATION . For wiring diagram, see WIRING DIAGRAMS article in this section.

1. Battery must be fully charged before proceeding. Attempt to start engine. If engine will not start, crank engine for at least 10 seconds. Connect DRB to Data Link Connector (DLC). Record DRB trouble codes.
2. If DRB displays ERROR message, go to «TEST NS-6A»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ns-6a-correcting-no-response) . If DRB has a blank screen or displays RAM TEST FAILURE, CARTRIDGE ERROR, KEY PAD TEST FAILURE, LOW BATTERY or HIGH BATTERY, DRB failure is indicated. To diagnose and correct problem, see VEHICLE COMMUNICATIONS in «TESTS W/CODES - BODY CONTROL COMPUTER»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-body-control-computer) article in this section. If DRB displays trouble codes, see «DRB TROUBLE CODES»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l) table and perform appropriate test(s). If DRB does not display codes, see «TEST NS-1A»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ns-1a-qualifying-no-start-condition) for no-start tests or «TEST NTC-1A»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l) for no trouble code tests.

DRB TROUBLE CODES

TEST TC-2A - NO CRANK REFERENCE SIGNAL AT PCM (DTC 11)

Note. For connector terminal identification, see CONNECTOR IDENTIFICATION . For wiring diagram, see WIRING DIAGRAMS article in this section.

1. Using DRB, erase trouble codes. Turn ignition on and then off. Attempt to start engine. If engine will not start, crank engine for at least 10 seconds.
2. Using DRB, read trouble codes. If DRB does not display NO CRANK REFERENCE SIGNAL AT PCM, condition required to set trouble code is not present at this time. Go to next step. If DRB displays NO CRANK REFERENCE SIGNAL AT PCM, go to step 6).
3. NO CRANK REFERENCE SIGNAL AT PCM trouble code sets if Powertrain Control Module (PCM) does not see a Crankshaft Position (CKP) sensor signal with Camshaft Position (CMP) sensor signal present. Possible causes are: failed CKP sensor, open or shorted CKP sensor signal circuit Red/Light Green wire, open or shorted CKP sensor 8-volt supply circuit White/Black wire, open CKP sensor ground circuit (Black/Light Blue wire), improperly adjusted CKP sensor, or failed (PCM). Go to next step.
4. Inspect all related wiring and connectors, and repair as necessary. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If no problems are found with wiring and connectors, go to next step.
5. Start engine. Wiggle wiring harness from CKP sensor to PCM. If engine misfires or stalls, repair wiring harness as necessary. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If engine does not misfire or stall, see INACTIVE TROUBLE CODE CONDITION in this article. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If engine does not misfire or stall, test is complete.
6. Turn ignition off. Disconnect Crankshaft Position (CKP) sensor connector. Using DRB in voltmeter mode, check voltage on CKP sensor connector, 8-volt supply circuit White/Black wire. If voltage is less than 7 volts, go to TEST TC-2B. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .
7. If voltage is more than 7 volts, turn ignition off. Connect a jumper wire to CKP sensor signal circuit Red/Light Green wire on CKP sensor connector harness side.
8. Using DRB, read trouble codes. Turn ignition off and then on. Using other end of jumper wire, make and break connection at CKP sensor ground circuit (Black/Light Blue wire) on sensor connector several times while observing DRB. If DRB displays NO CAM SYNC SIGNAL AT PCM, replace CKP. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .
9. If DRB does not display NO CAM SYNC SIGNAL AT PCM, turn ignition off. Using DRB in ohmmeter mode, check resistance of CKP sensor connector, ground circuit (Black/Light Blue wire). If resistance is more than 5 ohms, repair open Black/Light Blue wire. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .
10. If resistance is less than 5 ohms, disconnect Powertrain Control Module (PCM) connector. Inspect PCM connector for damaged or pushed-out terminals. Repair as necessary. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If PCM connector terminals are okay, go to next step.
11. Using an external ohmmeter, check resistance of signal circuit Red/Light Green wire between CKP sensor connector harness side and PCM connector terminal No. 24. If resistance is more than 5 ohms, repair open Red/Light Green or Gray/Black wire. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .
12. If resistance is less than 5 ohms, using DRB in ohmmeter mode, check resistance of PCM connector terminal No. 24, CKP sensor signal circuit Red/Light Green wire. If resistance is more than 5 ohms, replace PCM. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If resistance is less than 5 ohms, repair short to ground in Red/Light Green or Gray/Black wire. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .

TEST TC-2B - NO CRANK REFERENCE SIGNAL AT PCM

Note. For connector terminal identification, see CONNECTOR IDENTIFICATION . For wiring diagram, see WIRING DIAGRAMS article in this section.

1. Turn ignition off. Disconnect Camshaft Position (CMP) sensor connector. Inspect CMP sensor connector for damaged or pushed-out terminals. Repair as necessary. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If CMP sensor connector terminals are okay, go to next step.
2. Turn ignition on. Using DRB in voltmeter mode, check voltage on CMP sensor connector 8-volt supply circuit White/Black wire. If voltage is more than 7 volts, replace CMP sensor. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .
3. If voltage is less than 7 volts, turn ignition off. Disconnect Powertrain Control Module (PCM) connector. Inspect PCM connector for damaged or pushed-out terminals. Repair as necessary. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If PCM connector terminals are okay, go to next step.
4. Using DRB in ohmmeter mode, check resistance of Crankshaft Position Sensor (CKP) connector, 8-volt supply circuit White/Black wire. If resistance is less than 5 ohms, repair short to ground in Orange or White/Black wire. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .
5. If resistance is more than 5 ohms, check resistance of 8-volt supply circuit White/Black wire between CKP sensor harness side connector and PCM connector terminal No. 7 using an external ohmmeter. If resistance is more than 5 ohms, repair open Orange or White/Black wire. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If resistance is less than 5 ohms, replace PCM. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .

TEST TC-3A - NO CAM SYNC SIGNAL AT PCM (DTC 54)

Note. For connector terminal identification, see CONNECTOR IDENTIFICATION . For wiring diagram, see WIRING DIAGRAMS article in this section.

1. Using DRB, erase trouble codes. Attempt to start engine. If engine will not start, crank engine for at least 10 seconds.
2. Using DRB, read trouble codes. If DRB does not display NO CAM SYNC SIGNAL AT PCM, condition required to set trouble code is not present at this time. Go to next step. If DRB displays NO CAM SYNC SIGNAL AT PCM, go to step 6).
3. NO CAM SYNC SIGNAL AT PCM trouble code sets if Powertrain Control Module does not see Camshaft Position (CMP) sensor signal with Crankshaft Position (CKP) signal present. Possible causes are: failed CMP sensor, open or shorted CMP sensor signal circuit Gray/Black wire, open CMP sensor 8-volt supply circuit Black wire, open CMP sensor ground circuit (Black/Light Blue wire), improperly adjusted CMP sensor, or failed PCM. Go to next step.
4. Inspect all related wiring and connectors. Repair as necessary. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If no problems are found with wiring and connectors, go to next step.
5. Start engine. Wiggle wiring harness from CMP sensor to PCM. If engine misfires or stalls, repair wiring harness as necessary. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If engine does not misfire or stall, see INACTIVE TROUBLE CODE CONDITION in this article. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If engine does not misfire or stall, test is complete.
6. Turn ignition off. Disconnect Camshaft Position (CMP) sensor connector. Using DRB in voltmeter mode, check voltage on CMP sensor connector, 8-volt supply circuit White/Black wire. If voltage is less than 7 volts, repair open Orange or White/Black wire. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .
7. If voltage is more than 7 volts, connect a jumper wire to CMP signal circuit Gray/Black wire on CMP sensor connector harness side. Using other end of jumper wire, make and break connection at CMP sensor ground circuit (Black/Light Blue wire) on sensor connector several times. Without turning ignition off, attempt to start engine. If engine starts, replace CMP sensor. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If engine does not start, turn ignition off.
8. Remove distributor cap. While observing distributor rotor, have an assistant crank engine. If rotor does not turn as engine is cranked, repair distributor drive system as necessary. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .
9. If rotor turns, check resistance of CMP connector, sensor ground circuit (Black/Light Blue wire) using DRB in ohmmeter mode. If resistance is more than 5 ohms, repair open Black/Light Blue wire. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .
10. If resistance is less than 5 ohms, disconnect Powertrain Control Module (PCM) connector. Inspect PCM connector for damaged or pushed-out terminals. Repair as necessary. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If PCM connector terminals are okay, go to next step.
11. Using an external ohmmeter, check resistance of signal circuit Gray/Black wire between CMP sensor connector harness side and PCM connector terminal No. 44. If resistance is more than 5 ohms, repair open Tan/Yellow wire or Gray/Black wire. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .
12. If resistance is less than 5 ohms, check resistance of PCM connector terminal No. 44 Gray/Black wire using DRB in ohmmeter mode. If resistance is more than 5 ohms, replace PCM. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If resistance is less than 5 ohms, repair short to ground in Tan/Yellow wire or Gray/Black wire. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .

TEST TC-4A - SLOW CHANGE IN IDLE MAP SENSOR SIGNAL OR NO CHANGE IN MAP FROM START TO RUN (DTC 13)

Note. For connector terminal identification, see CONNECTOR IDENTIFICATION . For wiring diagram, see WIRING DIAGRAMS article in this section.

1. Turn ignition on. Using DRB, read trouble codes. If DRB displays MAP SENSOR VOLTAGE TOO LOW, go to TEST TC-5A. If DRB does not display MAP SENSOR VOLTAGE TOO LOW, go to next step.
2. Using DRB, erase trouble codes. Start engine. Allow engine to idle for 30 seconds. With engine running, use DRB to read trouble codes. If DRB displays NO CHANGE IN MAP FROM START TO RUN or SLOW CHANGE IN IDLE MAP SENSOR SIGNAL, go to step 7).
3. If DRB does not display NO CHANGE IN MAP FROM START TO RUN or SLOW CHANGE IN IDLE MAP SENSOR SIGNAL, use DRB to set engine speed to 1500 RPM. With engine running at 1500 RPM, read Manifold Absolute Pressure (MAP) sensor voltage on DRB. While Monitoring MAP sensor voltage, wiggle MAP sensor connector and wiring harness.
4. If engine stalls or MAP sensor voltage becomes erratic, inspect all related wiring and connectors. Repair wiring or connectors as necessary. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If engine does not stall and MAP sensor voltage does not become erratic, snap throttle open and closed while monitoring DRB.
5. If engine vacuum rapidly drops to less than one in. Hg, condition required to set trouble code is not present at this time. NO CHANGE IN MAP FROM START TO RUN trouble code sets if too small a difference is seen between barometric pressure at key on and manifold vacuum after engine start. SLOW CHANGE IN IDLE MAP SENSOR SIGNAL trouble code sets if variation in MAP signal is less than .157 volt and engine is at 600-1500 RPM. Possible causes for both these trouble codes are: restricted or leaking vacuum/pressure hose to MAP sensor, ice in MAP sensor or passage, or MAP sensor failure. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .
6. If engine vacuum does not rapidly drop to less than one in. Hg, remove MAP sensor. Inspect MAP sensor vacuum port and vacuum connector. If restriction exists, repair as necessary. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If restriction does not exist, replace MAP sensor. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .
7. Turn ignition off. Tee a vacuum gauge into Manifold Absolute Pressure (MAP) sensor vacuum hose. Start engine. With engine at idle, read vacuum gauge. If reading is zero in. Hg at idle, repair leak in vacuum hose to MAP sensor. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If reading is not zero in. Hg, snap throttle open and closed while monitoring DRB.
8. If engine vacuum does not rapidly drop, repair restricted vacuum hose. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If engine vacuum drops rapidly, turn ignition off. Disconnect MAP sensor connector. Turn ignition on. Using DRB in voltmeter mode, check voltage on MAP sensor connector, 5-volt sensor feed circuit (Violet/White wire). If voltage is less than 4 volts, repair open Violet/White wire. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If voltage is more than 5 volts, replace MAP sensor. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .

TEST TC-5A - MAP SENSOR VOLTAGE TOO LOW (DTC 14)

Note. For connector terminal identification, see CONNECTOR IDENTIFICATION . For wiring diagram, see WIRING DIAGRAMS article in this section.

1. Start engine. Using DRB, read Manifold Absolute Pressure (MAP) sensor voltage. If voltage is less than .2 volt, go to step 5). If voltage is more than .2 volt, turn engine off. Turn ignition on.
2. Using DRB, read MAP sensor voltage. If voltage is less than 1.2 volts, go to step 5). If voltage is more than 1.2 volts, wiggle MAP sensor connector and wiring harness while watching DRB display. If voltage changes, repair connector or wiring harness as necessary. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .
3. If voltage does not change, condition required to set trouble code is not present at this time. MAP SENSOR VOLTAGE TOO LOW trouble code sets if MAP sensor output is less than 1.2 volts at start or less than .2 volt with engine running. Engine speed must be more than 400 but less than 1500 RPM and Throttle Position Sensor (TPS) voltage must be less than one volt. Possible causes are: short to ground in MAP sensor signal circuit Red/White wire, MAP sensor shorted internally or loss of MAP sensor 5-volt supply circuit (Violet/White wire). Go to next step.
4. Inspect all related wiring and connectors. Repair as necessary. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If no problems are found with wiring and connectors, test is complete. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .
5. Turn ignition on. Ensure engine is off. Disconnect MAP sensor connector. Using DRB, read MAP sensor voltage. If voltage is more than 4 volts, replace MAP sensor. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .
6. If voltage is less than 4 volts, check voltage on MAP sensor connector, 5-volt supply circuit (Violet/White wire). If voltage is less than 64 volts, repair open Violet/White wire. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .
7. If voltage is more than 4 volts, turn ignition off. Disconnect Powertrain Control Module (PCM) connector. Using an external ohmmeter, check resistance between MAP sensor connector signal circuit Red/White wire and sensor ground circuit (Black/Light Blue wire).
8. If resistance is less than 5 ohms, repair Dark Green/Red wire or Red/White wire shorted to Black/Light Blue wire. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If resistance is more than 5 ohms, replace PCM. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .

TEST TC-6A - MAP SENSOR VOLTAGE TOO HIGH (DTC 14)

Note. For connector terminal identification, see CONNECTOR IDENTIFICATION . For wiring diagram, see WIRING DIAGRAMS article in this section.

1. Start engine. Using DRB, read Manifold Absolute Pressure (MAP) sensor voltage. If MAP sensor voltage is more than 4.6 volts, go to step 4). If MAP sensor voltage is less than 4.6 volts, wiggle MAP sensor connector and wiring harness while watching DRB display. If MAP sensor voltage changes, repair connector or wiring harness as necessary. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .
2. If MAP sensor voltage does not change, condition required to set trouble code is not present at this time. MAP SENSOR VOLTAGE TOO HIGH trouble code sets if MAP sensor output is more than 4.6 volts at start or with engine running. Engine speed must be more than 400 but less than 1500 RPM and Throttle Position Sensor (TPS) voltage must be less than one volt. Possible causes are: open MAP sensor signal circuit Red/White wire, MAP sensor open internally, open MAP sensor ground circuit (Black/Light Blue wire) or short to voltage in MAP sensor signal circuit Red/White wire. Go to next step.
3. Inspect all related wiring and connectors. Repair wiring or connectors as necessary. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If no problems are found with wiring and connectors, test is complete. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .
4. Turn ignition off. Disconnect MAP sensor connector. Connect a jumper wire between signal circuit Red/White wire and ground circuit (Black/Light Blue wire) on MAP sensor connector. Turn ignition on. Using DRB, read MAP sensor voltage. If DRB displays NO RESPONSE, repair MAP sensor signal circuit Red/White wire for a short to 5-volt supply circuit (Violet/White wire). Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If DRB does not display NO RESPONSE, go to next step.
5. If voltage is less than one volt, replace MAP sensor. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If MAP sensor voltage is more than one volt, move jumper wire from MAP sensor connector, ground circuit (Black/Light Blue wire) to an engine ground. Using DRB, read MAP sensor voltage.
6. If MAP sensor voltage is less than one volt, repair open Black/Light Blue wire. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If MAP sensor voltage is more than one volt, turn ignition off. Disconnect Powertrain Control Module (PCM) connector.
7. Using an external ohmmeter, check resistance of signal circuit Red/White wire between MAP sensor connector and PCM connector terminal No. 1. If resistance is less than 5 ohms, replace PCM. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If resistance is more than 5 ohms, repair open Dark Green/Red wire or Red/White wire. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .

TEST TC-7A - NO VEHICLE SPEED SENSOR SIGNAL (DTC 15)

Note. For connector terminal identification, see CONNECTOR IDENTIFICATION . For wiring diagram, see WIRING DIAGRAMS article in this section.

1. Raise vehicle so drive wheels are free to spin. Start engine. Using DRB, read Vehicle Speed Sensor (VSS) signal. Put transmission in any forward gear. If DRB displays more than zero MPH, go to next step. If DRB does not display more than zero MPH, go to step 4).
2. Condition required to set trouble code is not present at this time. NO VEHICLE SPEED SENSOR SIGNAL trouble code sets if Powertrain Control Module (PCM) does not see a VSS signal at PCM terminal No. 47 (White/Orange wire) under road load conditions. Possible causes are: open or shorted VSS signal circuit (White/Orange wire), open VSS sensor 8-volt supply circuit White/Black wire, open VSS sensor ground circuit (Black/Light Blue wire), failed VSS sensor, failed Daytime Running Light (DRL) module (if equipped), or failed PCM. Go to next step.
3. Inspect all related wiring and connectors. Repair as necessary. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If no problems are found with wiring and connectors, see INACTIVE TROUBLE CODE CONDITION in this article. Perform «TEST VER-1»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-1-no-start-verification) .
4. Turn ignition off. Disconnect Vehicle Speed Sensor (VSS) connector. Inspect VSS connector for damaged or pushed-out terminals. Repair as necessary. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If connector is okay, go to next step.
5. Using DRB in voltmeter mode, check voltage on VSS connector, 8-volt supply circuit White/Black wire. If voltage is less than 7 volts, repair open Orange wire or White/Black wire. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .
6. If voltage is more than 7 volts, check voltage on VSS connector, signal circuit (White/Orange wire). If voltage is less than 4 volts, go to TEST TC-7B. If voltage is more than 4 volts, connect a jumper wire between VSS signal circuit (White/Orange wire) and ground circuit (Black/Light Blue wire) on VSS sensor connector.
7. Turn ignition on. Using DRB, read vehicle speed. Make and break connection at VSS sensor connector several times while observing DRB display. If DRB does not display more than zero MPH, go to TEST 7B. If DRB displays more than zero MPH, remove VSS.
8. Inspect speedometer pinion gear. Repair as necessary. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If pinion gear is okay, replace VSS. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .

TEST TC-7B - NO VEHICLE SPEED SENSOR SIGNAL

Note. For connector terminal identification, see CONNECTOR IDENTIFICATION . For wiring diagram, see WIRING DIAGRAMS article in this section.

1. Turn ignition off. Using DRB in ohmmeter mode, check resistance of VSS connector, sensor ground circuit (Black/Light Blue wire). If resistance is more than 5 ohms, repair open Black/Light Blue wire. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If resistance is less than 5 ohms, ensure ignition is off.
2. Disconnect Powertrain Control Module (PCM) connector. Inspect PCM connector for damaged or pushed out terminals. Repair as necessary. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If connector is okay, go to next step.
3. Using an external ohmmeter, check resistance of VSS signal circuit (White/Orange) wire between VSS connector and PCM connector terminal No. 47. If resistance is more than 5 ohms, repair open White/Orange wire. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .
4. If resistance is less than 5 ohms, check resistance of PCM connector terminal No. 47 (White/Orange wire) using DRB in ohmmeter mode. If resistance is more than 5 ohms, replace PCM. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If resistance is less than 5 ohms, repair short to ground in White/Orange wire. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .

TEST TC-7C - NO VEHICLE SPEED SENSOR SIGNAL

Note. For connector terminal identification, see CONNECTOR IDENTIFICATION . For wiring diagram, see WIRING DIAGRAMS article in this section.

1. Turn ignition off. Using DRB in ohmmeter mode, check resistance of VSS connector, sensor ground circuit (Black/Light Blue wire). If resistance is more than 5 ohms, repair open Black/Light Blue wire. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If resistance is less than 5 ohms, ensure ignition is off.
2. Disconnect Powertrain Control Module (PCM) connector. Inspect PCM connector for damaged or pushed out terminals. Repair as necessary. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If connector is okay, go to next step.
3. Using an external ohmmeter, check resistance White/Orange wire between VSS connector and PCM connector terminal No. 47. If resistance is more than 5 ohms, repair open White/Orange wire. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .
4. If resistance is less than 5 ohms, check resistance of PCM connector terminal No. 47 (White/Orange wire) using DRB in ohmmeter mode. If resistance is more than 5 ohms, replace PCM. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If resistance is less than 5 ohms, short to ground in White/Orange wire. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .

TEST TC-8A - LEFT O2S SENSOR STAYS AT CENTER (DTC 21)

Note. For connector terminal identification, see CONNECTOR IDENTIFICATION . For wiring diagram, see WIRING DIAGRAMS article in this section.

1. Start engine. Allow engine to run until normal operating temperature is reached. Using DRB, set engine speed to 1500 RPM. Using DRB, read oxygen (O2) sensor state. NOTE: DRB displays dual O2 sensors as LT O2S and RT O2S. On systems equipped with dual O2 sensors, DRB will read LT O2S in following step. NOTE: ZJ models have one oxygen sensor. Only LEFT O2S DRB messages apply. If messages for RIGHT O2S appear, DRB may be faulty.
2. If O2 sensor is not switching from rich to lean, go to step 6). If O2 sensor is switching from rich to lean, wiggle sensor connector and wiring harness while watching DRB display.
3. If O2 sensor is locked at center at any time, inspect all related wiring, paying particular attention to O2 sensor signal circuit Black/Orange wire and connectors. Repair as necessary. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If O2 sensor is not locked at center at any time, condition required to set trouble code is not present at this time. Go to next step.
4. LEFT O2S STAYS AT CENTER trouble code sets if O2 sensor output voltage stays at .5 volt for 1.5 minutes with engine temperature more than 170°F (77°C) and engine running for 2 minutes. Possible causes are: open O2 sensor circuit or O2 sensor failure. Go to next step.
5. Inspect all related wiring and connectors. Repair as necessary. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If no problems are found with wiring and connectors, test is complete. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .
6. Turn ignition off. Disconnect O2 sensor connector (on dual O2 sensor system, disconnect left connector). Using DRB in ohmmeter mode, check resistance of ground circuit (Black/Light Blue wire) at O2 sensor connector harness side. If resistance is more than 5 ohms, repair open Black/Light Blue wire. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .
7. If resistance is less than 5 ohms, connect a jumper wire between O2 sensor signal circuit Black/Orange wire and battery positive terminal. Using DRB, read O2 sensor voltage. If O2 sensor voltage is more than one volt, replace O2 sensor. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .
8. If O2 sensor voltage is less than one volt, turn ignition off. Disconnect Powertrain Control Module (PCM) connector. Disconnect jumper wire between O2 sensor connector and battery positive terminal.
9. Using an external ohmmeter, check resistance of signal circuit Black/Orange wire between O2 sensor connector harness side and PCM connector terminal No. 41. If resistance is less than 5 ohms, replace PCM. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If resistance is more than 5 ohms, repair open Dark Green/White wire or Black/Orange wire. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .
10. Turn ignition off. Disconnect O2 sensor connector (on dual O2 sensor system, disconnect left connector). Using DRB in ohmmeter mode, check resistance of ground circuit (Black/Light Blue wire) at O2 sensor connector harness side. If resistance is more than 5 ohms, repair open Black/Light Blue wire. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .
11. If resistance is less than 5 ohms, connect a jumper wire between O2 sensor signal circuit (Tan/White wire) and battery positive terminal. Using DRB, read O2 sensor voltage. If O2 sensor voltage is more than one volt, replace O2 sensor. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .
12. If O2 sensor voltage is less than one volt, turn ignition off. Disconnect Powertrain Control Module (PCM) connector. Disconnect jumper wire between O2 sensor connector and battery positive terminal.
13. Using an external ohmmeter, check resistance of signal circuit (Tan/White wire) between O2 sensor connector harness side and PCM connector terminal No. 23. If resistance is less than 5 ohms, replace PCM. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If resistance is more than 5 ohms, repair open Tan/White wire. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .

TEST TC-9A - RIGHT O2S STAYS AT CENTER (DTC 21)

Note. ZJ models have one oxygen sensor. Only LEFT O2S DRB messages apply. If messages for RIGHT O2S appear, DRB may be faulty.

TEST TC-10A - LEFT O2S STAYS ABOVE CENTER (RICH) (DTC 52)

Note. For connector terminal identification, see CONNECTOR IDENTIFICATION . For wiring diagram, see WIRING DIAGRAMS article in this section.

1. Start engine. Allow engine to run until normal operating temperature is reached. If vehicle is not equipped with dual oxygen (O2) sensors, go to step 5). If vehicle is equipped with dual O2 sensors, go to next step. NOTE: DRB displays dual O2 sensors as LT O2S and RT O2S. NOTE: ZJ models have one oxygen sensor. Only LEFT O2S DRB messages apply. If messages for RIGHT O2S appear, DRB may be faulty.
2. Using DRB, set engine speed to 1500 RPM. Using DRB, read LT O2S sensor voltage. If O2 sensor voltage is not always more than .5 volt, condition required to set trouble code is not present at this time. Go to next step. If O2 sensor voltage is always more than .5 volt, go to step 4).
3. LEFT O2S STAYS ABOVE CENTER (RICH) trouble code sets if O2 sensor output voltage stays at more than .5 volt, but less than 1.2 volts, for 8 minutes. Possible causes are: high fuel pressure, other engine sensor calibration failures, ignition system failure, O2 sensor failure or fuel contamination. Go to TEST NTC-1A.
4. If RIGHT O2S STAYS ABOVE CENTER (RICH) trouble code is not also set, replace leaking injector for left intake manifold bank. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If RIGHT O2S STAYS ABOVE CENTER (RICH) trouble code is also set, a condition causing engine to run rich in all cylinders is indicated. Go to TEST NTC-1A.
5. Using DRB, set engine speed to 1500 RPM. Using DRB, read O2 sensor voltage. If O2 sensor voltage is not always more than .5 volt, condition required to set trouble code is not present at this time. Go to next step. If O2 sensor voltage is always more than .5 volt, a condition causing engine to run rich in all cylinders is indicated. Go to TEST NTC-1A.
6. LEFT O2S STAYS ABOVE CENTER (RICH) trouble code sets if O2 sensor output voltage stays at more than .5 volt, but less than 1.2 volts, for 8 minutes. Possible causes are: high fuel pressure, other engine sensor calibration failures, ignition system failure, O2 sensor failure or fuel contamination. Go to TEST NTC-1A.

TEST TC-11A - RIGHT O2S STAYS ABOVE CENTER (RICH) (DTC 52)

Note. ZJ models have one oxygen sensor. Only LEFT O2S DRB messages apply. If messages for RIGHT O2S appear, DRB may be faulty.

TEST TC-12A - LEFT O2S STAYS BELOW CENTER (LEAN) (DTC 51)

Note. For connector terminal identification, see CONNECTOR IDENTIFICATION . For wiring diagram, see WIRING DIAGRAMS article in this section.

1. Start engine. Allow engine to run until normal operating temperature is reached. Go to next step. NOTE: DRB displays dual O2 sensors as LT O2S and RT O2S. NOTE: ZJ models have one oxygen sensor. Only LEFT O2S DRB messages apply. If messages for RIGHT O2S appear, DRB may be faulty.
2. Using DRB, set engine speed to 1500 RPM. Using DRB, read O2 sensor voltage. If O2 sensor voltage is not always less than .5 volt, condition required to set trouble code is not present at this time. Go to next step. If O2 sensor voltage is always less than .5 volt, a condition causing engine to run lean in all cylinders is indicated. Go to TEST NTC-1A.
3. LEFT O2S STAYS BELOW CENTER (LEAN) trouble code sets if O2 sensor output voltage stays at less than .5 volt for 8 minutes. Possible causes are: major vacuum leak, low fuel pressure, other engine sensor calibration failures, ignition system failure, O2 sensor failure or fuel contamination. Go to TEST NTC-1A.

TEST TC-13A - RIGHT O2S STAYS BELOW CENTER (LEAN) (DTC 51)

Note. ZJ models have one oxygen sensor. Only LEFT O2S DRB messages apply. If messages for RIGHT O2S appear, DRB may be faulty.

TEST TC-14A - LEFT O2S SHORTED TO VOLTAGE (DTC 21)

Note. For connector terminal identification, see CONNECTOR IDENTIFICATION . For wiring diagram, see WIRING DIAGRAMS article in this section.

Note. ZJ models have one oxygen sensor. Only LEFT O2S DRB messages apply. If messages for RIGHT O2S appear, DRB may be faulty.

1. Using DRB, read O2 sensor voltage. If voltage is less than 1.2 volts, go to next step. If voltage is more than 1.2 volts, disconnect O2 sensor connector. If voltage is less than 1.2 volts, replace O2 sensor. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If voltage is more than 1.2 volts, repair short to ground in O2 sensor connector, signal circuit Black/Orange wire. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .
2. While observing DRB, wiggle wiring harness from O2 sensor connector to Powertrain Control Module (PCM). If voltage increases to more than 1.2 volts at any time, repair wiring harness as necessary. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If voltage does not increase to more than 1.2 volts at any time, condition required to set trouble code is not present at this time.
3. LEFT O2S SHORTED TO VOLTAGE trouble code sets if O2 sensor signal circuit Black/Orange wire voltage is more than 1.2 volts. Possible causes are: sensor signal circuit shorted to another circuit, dirty or wet connection causing voltage tracking in connector, or O2 sensor failure. Go to next step.
4. While monitoring DRB, wiggle wiring harness between O2 sensor connector and PCM. If voltage increases to more than 1.2 volts at any time, repair wiring harness as necessary. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If voltage does not increase to more than 1.2 volts at any time, condition required to set trouble code is not present at this time. Go to next step.
5. Inspect all related wiring and connectors. Repair as necessary. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If no problems are found in wiring or connectors, see INACTIVE TROUBLE CODE CONDITION in this article.

TEST TC-15A - RIGHT O2S SHORTED TO VOLTAGE (DTC 21)

Note. ZJ models have one oxygen sensor. Only LEFT O2S DRB messages apply. If messages for RIGHT O2S appear, DRB may be faulty.

TEST TC-16A - RIGHT/LEFT IDLE ADAPTIVE MEM AT LEAN/RICH LIMIT (DTC 52)

Note. ZJ models have one oxygen sensor. Only LEFT O2S DRB messages apply. If messages for RIGHT O2S appear, DRB may be faulty.

These trouble codes may set for several reasons not related to Powertrain Control Module (PCM) electronics. Idle adaptive memory is designed to aid in air/fuel control. Its function is to adapt air/fuel mixture to correct for fuel pressure differences and mechanical changes such as engine wear and mechanical malfunctions.

These trouble codes affect following systems

1. Dual Oxygen (O2) Sensor System

PCM reaches its operating limit when one O2 sensor indicates a continuous lean or rich exhaust gas mixture. O2 sensor responsible is disabled and other O2 sensor takes over. If both sensors are indicating excessive lean or rich readings, fuel control system goes into open loop mode.

1. Single Oxygen (O2) Sensor System

Fuel control system goes into open loop when O2 sensor indicates a continuous lean or rich exhaust gas mixture.

Following definitions apply to RIGHT (or LEFT) IDLE ADAPTIVE MEM AT LEAN (or RICH) message

1. RIGHT (Or LEFT) IDLE ADAPTIVE MEM AT LEAN PCM tries to adapt air/fuel mixture richer.
2. RIGHT (Or LEFT) IDLE ADAPTIVE MEM AT RICH PCM tries to adapt air/fuel mixture leaner.

Possible causes of RIGHT (or LEFT) IDLE ADAPTIVE MEM AT LEAN (or RICH) message are

1. Excessive engine wear.
2. Incorrect fuel pressure.
3. Mechanical malfunctions.

TEST TC-17A - ECT SENSOR VOLTAGE TOO LOW (DTC 22)

Note. For connector terminal identification, see CONNECTOR IDENTIFICATION . For wiring diagram, see WIRING DIAGRAMS article in this section.

1. Using DRB, read Engine Coolant Temperature (ECT) sensor voltage. If voltage is less than 0.5 volt, go to step 4). If voltage is more than 0.5 volt, wiggle wiring harness from ECT sensor to Powertrain Control Module (PCM) while observing DRB. If voltage changes, repair wiring harness as necessary. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .
2. If voltage does not change, condition required to set trouble code is not present at this time. ECT SENSOR VOLTAGE TOO LOW trouble code sets if ECT sensor signal circuit (Tan/Black wire) is less than 0.5 volt. Possible causes are: short to ground in ECT sensor signal circuit (Tan/Black wire) or ECT sensor shorted internally. Go to next step.
3. Inspect all related wiring and connectors. Repair as necessary. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If no problems are found with wiring and connectors, see INACTIVE TROUBLE CODE CONDITION in this article. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .
4. Disconnect ECT sensor connector. Using DRB, read ECT sensor voltage. If voltage is more than 4 volts, replace ECT sensor. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If voltage is less than 4 volts, turn ignition off. Disconnect Powertrain Control Module (PCM) connector.
5. Using DRB in ohmmeter mode, check resistance of ECT sensor connector, signal circuit (Tan/Black wire). If resistance is less than 5 ohms, repair short to ground in Tan/Black wire. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .
6. If resistance is more than 5 ohms, check resistance between ECT sensor connector, signal circuit (Tan/Black wire) and ground circuit (Black/Light Blue wire) using an external ohmmeter. If resistance is less than 5 ohms, repair Tan/Black wire shorted to Black/Light Blue wire. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If resistance is more than 5 ohms, replace PCM. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .

TEST TC-18A - ECT SENSOR VOLTAGE TOO HIGH (DTC 22)

Note. For connector terminal identification, see CONNECTOR IDENTIFICATION . For wiring diagram, see WIRING DIAGRAMS article in this section.

1. Using DRB, read Engine Coolant Temperature (ECT) sensor voltage. If voltage is more than 4.9 volts, go to step 4). If voltage is less than 4.9 volts, wiggle wiring harness from ECT sensor to Powertrain Control Module (PCM) while observing DRB. If voltage changes, repair wiring harness as necessary. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .
2. If voltage does not change, condition required to set trouble code is not present at this time. ECT SENSOR VOLTAGE TOO HIGH trouble code sets if ECT sensor signal circuit (Tan/Black wire) is more than 4.9 volts. Possible causes are: open ECT sensor signal circuit (Tan/Black wire), ECT sensor open internally, or open ECT sensor ground circuit (Black/Light Blue wire).
3. Inspect all related wiring and connectors. Repair as necessary. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If no problems are found with wiring and connectors, see INACTIVE TROUBLE CODE CONDITION in this article. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .
4. Disconnect ECT sensor connector. Connect a jumper wire between signal circuit (Tan/Black wire) and ground circuit (Black/Light Blue wire) on ECT sensor connector. Using DRB, read ECT sensor voltage.
5. If voltage is less than one volt, replace ECT sensor. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If voltage is more than one volt, move jumper wire from ECT sensor connector, ground circuit (Black/Light Blue wire), to engine ground.
6. Using DRB, read ECT sensor voltage. If voltage is less than one volt, repair open Black/Light Blue wire. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If voltage is more than one volt, turn ignition off. Disconnect Powertrain Control Module (PCM) connector.
7. Using an external ohmmeter, check resistance of signal circuit (Tan/Black wire) between ECT sensor connector and PCM connector terminal No. 2. If resistance is more than 5 ohms, repair open Tan/Black wire. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If resistance is less than 5 ohms, replace PCM. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .

TEST TC-19A - INTAKE AIR TEMP SENSOR VOLTAGE LOW (DTC 23)

Note. For connector terminal identification, see CONNECTOR IDENTIFICATION . For wiring diagram, see WIRING DIAGRAMS article in this section.

1. Using DRB, read Intake Air Temperature (IAT) sensor voltage. If IAT sensor voltage is less than .5 volt, go to step 4). If IAT sensor voltage is more than .5 volt, wiggle wiring harness from IAT sensor to Powertrain Control Module (PCM) while observing DRB. If voltage changes, repair wiring harness as necessary.
2. If voltage does not change, condition required to set trouble code is not present at this time. INTAKE AIR TEMP SENSOR VOLTAGE LOW trouble code sets if IAT sensor signal circuit (Black/Red wire) is less than .5 volt. Possible causes are: short to ground in IAT signal circuit (Black/Red wire) or IAT sensor shorted internally. Go to next step.
3. Inspect all related wiring and connectors. Repair as necessary. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If no problems are found with wiring and connectors, see INACTIVE TROUBLE CODE CONDITION in this article. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .
4. Disconnect IAT sensor connector. Using DRB, read IAT sensor voltage. If voltage is more than 4 volts, replace IAT sensor. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If voltage is less than 4 volts, turn ignition off. Disconnect Powertrain Control Module (PCM) connector.
5. Using an external ohmmeter, check resistance between IAT sensor connector, signal circuit (Black/Red wire) and ground circuit (Black/Light Blue wire). If resistance is less than 5 ohms, repair Black/Red wire shorted to Black/Light Blue wire. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .
6. If resistance is more than 5 ohms, using DRB in ohmmeter mode, check resistance of IAT sensor connector, signal circuit (Black/Red wire). If resistance is less than 5 ohms, repair short to ground in Black/Red wire. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If resistance is more than 5 ohms, replace PCM. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .

TEST TC-20A - INTAKE AIR TEMP SENSOR VOLTAGE HIGH (DTC 23)

Note. For connector terminal identification, see CONNECTOR IDENTIFICATION . For wiring diagram, see WIRING DIAGRAMS article in this section.

1. Using DRB, read Intake Air Temperature (IAT) sensor voltage. If IAT sensor voltage is more than 4.5 volts, go to step 4). If IAT sensor voltage is less than 4.5 volts, wiggle wiring harness from IAT sensor to Powertrain Control Module (PCM) while observing DRB display. If voltage changes, repair wiring harness as necessary.
2. If voltage does not change, condition required to set trouble code is not present at this time. INTAKE AIR TEMP SENSOR VOLTAGE HIGH trouble code sets if IAT sensor signal circuit (Black/Red wire) is more than 4.9 volts. Possible causes are: open IAT sensor signal circuit (Black/Red wire), IAT sensor open internally or open IAT sensor ground circuit (Black/Light Blue wire). Go to next step.
3. Inspect all related wiring and connectors. Repair as necessary. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If no problems are found with wiring and connectors, see INACTIVE TROUBLE CODE CONDITION in this article. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .
4. Disconnect IAT sensor connector. Connect jumper wire between signal circuit (Black/Red wire) and ground circuit (Black/Light Blue wire) on IAT sensor connector. Using DRB, read IAT sensor voltage. If voltage is less than one volt, replace IAT sensor. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .
5. If voltage is more than one volt, move jumper wire from IAT sensor connector, ground circuit (Black/Light Blue wire) to an engine ground. Using DRB, read IAT sensor voltage. If voltage is less than one volt, repair open Black/Light Blue wire. If voltage is more than one volt, turn ignition off. Disconnect Powertrain Control Module (PCM) connector.
6. Using an external ohmmeter, check resistance of signal circuit (Black/Red wire) between IAT sensor connector and PCM connector terminal No. 21. If resistance is more than 5 ohms, repair open Black/Red wire. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If resistance is less than 5 ohms, replace PCM. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .

TEST TC-21A - THROTTLE POSITION SENSOR VOLTAGE LOW (DTC 24)

Note. For connector terminal identification, see CONNECTOR IDENTIFICATION . For wiring diagram, see WIRING DIAGRAMS article in this section.

1. Using DRB, read Throttle Position Sensor (TPS) voltage. If TPS voltage is less than .2 volt, go to step 5). If TPS voltage is more than .2 volt, slowly open and close throttle while observing DRB.
2. If voltage change is not smooth, replace TPS. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If voltage change is smooth, wiggle wiring harness from TPS to Powertrain Control Module (PCM) while observing DRB. If voltage changes, repair wiring harness as necessary. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .
3. If voltage does not change, condition required to set trouble code is not present at this time. THROTTLE POSITION SENSOR VOLTAGE LOW trouble code sets if TPS signal circuit (Orange/Dark Blue wire) is less than .2 volt or if vehicle speed is more than 20 MPH, engine speed is more than 1500 RPM and vacuum is less than 2 in. Hg with TPS signal circuit (Orange/Dark Blue wire) less than .5 volt. Possible causes are: short to ground in TPS signal circuit (Orange/Dark Blue wire), TPS sensor failure or open TPS 5-volt supply circuit (Violet/White wire). Go to next step.
4. Inspect all related wiring and connectors. Repair as necessary. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If no problems are found with wiring and connectors, condition required to set trouble code is not present at this time. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .
5. Disconnect TPS connector. Using DRB, read TPS voltage. If voltage is more than one volt, replace TPS. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If voltage is less than one volt, go to next step.
6. Using DRB, check voltage on TPS connector, 5-volt supply circuit (Violet/White wire). If voltage is less than 4 volts, repair open Violet/White wire. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .
7. If voltage is more than 4 volts, turn ignition off. Disconnect Powertrain Control Module (PCM) connector. Using DRB in ohmmeter mode, check resistance of TPS connector, signal circuit (Orange/Dark Blue wire). If resistance is more than 5 ohms, replace PCM. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If resistance is less than 5 ohms, repair short to ground in Orange/Dark Blue wire. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .

TEST TC-22A - THROTTLE POSITION SENSOR VOLTAGE HIGH (DTC 24)

Note. For connector terminal identification, see CONNECTOR IDENTIFICATION . For wiring diagram, see WIRING DIAGRAMS article in this section.

1. Using DRB, read Throttle Position Sensor (TPS) voltage. If voltage is more than 4.5 volts, go to step 5). If TPS voltage is less than 4.5 volts, slowly open and close throttle while observing DRB.
2. If voltage change is not smooth, replace TPS. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If voltage change is smooth, wiggle wiring harness from TPS to Powertrain Control Module (PCM) while observing DRB. If voltage changes, repair wiring harness as necessary. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .
3. If voltage does not change, condition required to set trouble code is not present at this time. THROTTLE POSITION SENSOR VOLTAGE HIGH trouble code sets if TPS signal circuit (Orange/Dark Blue wire) is more than 4.5 volts. Possible causes are: open TPS signal circuit (Orange/Dark Blue wire), open TPS ground circuit (Black/Light Blue wire) or TPS sensor failure. Go to next step.
4. Inspect all related wiring and connectors. Repair as necessary. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If no problems are found with wiring and connectors, condition required to set trouble code is not present at this time. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .
5. Disconnect TPS connector. Connect a jumper wire between TPS signal circuit (Orange/Dark Blue wire) and TPS ground circuit (Black/Light Blue wire) on TPS connector. Using DRB, read TPS voltage. If DRB displays NO RESPONSE, repair Orange/Dark Blue wire shorted to Violet/White wire. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If voltage is less than one volt, replace TPS. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .
6. If voltage is more than one volt, move jumper wire from TPS connector, ground circuit (Black/Light Blue wire), to an engine ground. Using DRB, read TPS sensor voltage.
7. If voltage is less than one volt, repair open Black/Light Blue wire. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If voltage is more than one volt, turn ignition off. Disconnect Powertrain Control Module (PCM) connector.
8. Using an external ohmmeter, check resistance of TPS signal circuit (Orange/Dark Blue wire) between TPS connector and PCM connector terminal No. 22. If resistance is less than 5 ohms, replace PCM. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If resistance is more than 5 ohms, repair open Orange/Dark Blue wire. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .

TEST TC-23A - IDLE AIR CONTROL MOTOR CIRCUITS (DTC 25)

Note. For connector terminal identification, see CONNECTOR IDENTIFICATION . For wiring diagram, see WIRING DIAGRAMS article in this section.

1. Turn ignition off. Connect a tachometer. Start engine. Allow engine to idle for 20 seconds. Using DRB, actuate Idle Air Control (IAC) motor to 1400 RPM. If tachometer does not read 1300-1500 RPM, go to step 6).
2. If tachometer reads 1300-1500 RPM, using DRB, actuate IAC motor to 900 RPM. If tachometer does not read 800-1000 RPM, go to step 6). If tachometer reads 800-1000 RPM, condition required to set trouble code is not present at this time. Go to next step.
3. IDLE AIR CONTROL MOTOR CIRCUITS trouble code sets if any of 4 Idle Air Control (IAC) motor wires is shorted to ground or battery voltage. Possible causes are: IAC motor internally shorted or IAC motor wires shorted together. Go to next step.
4. Inspect all related wiring and connectors. Repair as necessary. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If no problems are found with wiring and connectors, start engine. Allow engine to run until normal operating temperature is reached. Using DRB, actuate IAC wiggle test. Idle speed should increase and decrease in relation to DRB display. If engine speed does not change as specified, go to step 6).
5. If engine speed changes as specified, wiggle wiring harness from IAC motor to Powertrain Control Module (PCM) while observing IAC motor operation. If IAC motor stops operating at any time, repair wiring harness as necessary. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If no problems were found with wiring and connectors, see INACTIVE TROUBLE CODE CONDITION in this article. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .
6. Turn ignition off. Disconnect Idle Air Control (IAC) motor connector. Inspect IAC motor connector for damaged, pushed-out or miswired terminals. Repair as necessary. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If connector is okay, go to next step.
7. Using DRB, check resistance of all wires on IAC motor connector. If resistance for any wire is less than 5 ohms, repair appropriate wire for a short to ground. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .
8. If resistance for all wires is more than 5 ohms, using DRB, actuate IAC motor. Using DRB in voltmeter mode, check voltage on each IAC motor connector wire. If voltage for any wire is less than 5 volts at all times, go to appropriate test. See «IAC DRIVER TEST»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l) table. If voltage for all wires is more than 5 volts at any time, go to next step. IAC DRIVER TEST Driver No. Wire Color Test No. 1 BRN/WHT «TEST TC-23B»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-tc-23b-iac-driver-1) 2 Violet/Black «TEST TC-23C»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-tc-23c-iac-driver-2) 3 Yellow/Black «TEST TC-23D»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-tc-23d-iac-driver-3) 4 Gray/Red «TEST TC-23E»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-tc-23e-iac-driver-4)
9. Turn ignition off. Disconnect Powertrain Control Module (PCM) connector. Using an external ohmmeter, check and record resistance readings between following driver circuits. Refer to the «IAC DRIVER CIRCUIT IDENTIFICATION»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l) table: Driver circuit No. 1 and circuits No. 2, 3 and 4. Driver circuit No. 2 and circuits No. 3 and 4. Driver circuit No. 3 and circuit No. 4. IAC DRIVER CIRCUIT IDENTIFICATION Driver No. Wire Color 1 Brown/White 2 Violet/Black 3 Yellow/Black 4 Gray/Red
10. If resistance between any 2 wires is less than 5 ohms, repair those 2 wires for shorting together. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If resistance between all pairs of wires is more than 5 ohms, replace IAC motor. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .

TEST TC-23B - IAC DRIVER #1 CONTROL CIRCUIT

Note. For connector terminal identification, see CONNECTOR IDENTIFICATION . For wiring diagram, see WIRING DIAGRAMS article in this section.

1. Turn ignition off. Disconnect Powertrain Control Module (PCM) connector. Inspect connector for damaged, pushed-out or miswired terminals. Repair as necessary. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If connector is okay, go to next step.
2. Using an external ohmmeter, check resistance of Idle Air Control (IAC) motor driver No. 1 circuit (Brown/White wire) between IAC motor connector and PCM terminal No. 40. If resistance is less than 5 ohms, replace PCM. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If resistance is more than 5 ohms, repair open Brown/White wire. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .

TEST TC-23C - IAC DRIVER #2 CONTROL CIRCUIT

Note. For connector terminal identification, see CONNECTOR IDENTIFICATION . For wiring diagram, see WIRING DIAGRAMS article in this section.

1. Turn ignition off. Disconnect Powertrain Control Module (PCM) connector. Inspect connector for damaged, pushed-out or miswired terminals. Repair as necessary. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If connector is okay, go to next step.
2. Using an external ohmmeter, check resistance of Idle Air Control (IAC) motor driver No. 2 circuit Violet/Black wire between IAC motor connector and PCM terminal No. 60. If resistance is less than 5 ohms, replace PCM. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If resistance is more than 5 ohms, repair open Yellow/Black wire or Violet/Black wire. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .

TEST TC-23D - IAC DRIVER #3 CONTROL CIRCUIT

Note. For connector terminal identification, see CONNECTOR IDENTIFICATION . For wiring diagram, see WIRING DIAGRAMS article in this section.

1. Turn ignition off. Disconnect Powertrain Control Module (PCM) connector. Inspect connector for damaged, pushed-out or miswired terminals. Repair as necessary. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If connector is okay, go to next step.
2. Using an external ohmmeter, check resistance of Idle Air Control (IAC) motor driver No. 3 circuit Yellow/Black wire between IAC motor connector and PCM terminal No. 39. If resistance is less than 5 ohms, replace PCM. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If resistance is more than 5 ohms, repair open Gray/Red wire or Yellow/Black wire. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .

TEST TC-23E - IAC DRIVER #4 CONTROL CIRCUIT

Note. For connector terminal identification, see CONNECTOR IDENTIFICATION . For wiring diagram, see WIRING DIAGRAMS article in this section.

1. Turn ignition off. Disconnect Powertrain Control Module (PCM) connector. Inspect connector for damaged, pushed-out or miswired terminals. Repair as necessary. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If connector is okay, go to next step.
2. Using an external ohmmeter, check resistance of Idle Air Control (IAC) motor driver No. 4 circuit Gray/Red wire between IAC motor connector and PCM terminal No. 59. If resistance is less than 5 ohms, replace PCM. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If resistance is more than 5 ohms, repair open Violet/Black wire or Gray/Red wire. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .

TEST TC-24A - INJECTOR CONTROL CIRCUITS (DTC 27)

Note. For connector terminal identification, see CONNECTOR IDENTIFICATION . For wiring diagram, see WIRING DIAGRAMS article in this section.

1. Using DRB, erase trouble codes. Attempt to start engine. If engine will not start, crank engine for at least 10 seconds.
2. Using DRB, read trouble codes. If engine starts, allow engine to idle for at least 20 seconds. If DRB does not display INJECTOR CONTROL CIRCUIT, condition required to set trouble code is not present at this time. Go to next step. If DRB displays INJECTOR CONTROL CIRCUIT, go to appropriate test. See INJECTOR TROUBLE CODES table. INJECTOR TROUBLE CODES Trouble Code Go To INJECTOR #1 CONTROL CIRCUIT «TEST TC-24B»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-tc-24b-injector-1-control) INJECTOR #2 CONTROL CIRCUIT «TEST TC-25A»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-tc-25a-injector-2-control) INJECTOR #3 CONTROL CIRCUIT «TEST TC-26A»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-tc-26a-injector-3-control) INJECTOR #4 CONTROL CIRCUIT «TEST TC-27A»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-tc-27a-injector-4-control) INJECTOR #5 CONTROL CIRCUIT «TEST TC-28A»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-tc-28a-injector-5-control) INJECTOR #6 CONTROL CIRCUIT «TEST TC-29A»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-tc-29a-injector-6-control) INJECTOR #7 CONTROL CIRCUIT «TEST TC-30A»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-tc-30a-injector-7-control) INJECTOR #8 CONTROL CIRCUIT «TEST TC-31A»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-tc-31a-injector-8-control)
3. INJECTOR CONTROL CIRCUIT trouble code sets if Powertrain Control Module (PCM) does not detect injector "turn-off edge" when expected. Possible causes are: open or shorted injector control circuit, open injector power supply circuit, open injector, or failed driver in PCM. Go to next step.
4. Inspect all related wiring and connectors. Repair as necessary. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If no problems are found with wiring and connectors, go to next step.
5. Start engine. Wiggle wiring harness from injectors to PCM. If engine misfires or stalls, repair wiring harness as necessary. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If engine does not misfire or stall, see INACTIVE TROUBLE CODE CONDITION in this article. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .

TEST TC-24B - INJECTOR #1 CONTROL CIRCUIT

Note. For connector terminal identification, see CONNECTOR IDENTIFICATION . For wiring diagram, see WIRING DIAGRAMS article in this section.

1. Turn ignition off. Disconnect injector No. 1 connector. Using an external ohmmeter, check resistance between injector terminals. If resistance is not 10-16 ohms, replace injector. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If resistance is 10-16 ohms, turn ignition on.
2. Using DRB, actuate injector No. 1. Using DRB in voltmeter mode, check voltage on injector No. 1 connector, Auto Shutdown (ASD) output circuit Green/Black wire. If voltage is less than 10 volts, repair open Dark Green/Orange wire or Dark Green/Black wire. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If voltage is more than 10 volts, turn ignition off.
3. Disconnect Powertrain Control Module (PCM) connector. Using an external ohmmeter, check resistance of injector No. 1 driver circuit (White/Dark Blue wire) between injector connector (harness side) and PCM connector terminal No. 16. If resistance is more than 5 ohms, repair open White/Dark Blue wire. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .
4. If resistance is less than 5 ohms, using DRB in ohmmeter mode, check resistance of PCM terminal No. 16 (White/Dark Blue wire). If resistance is less than 5 ohms, repair short to ground in White/Dark Blue wire. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If resistance is more than 5 ohms, replace PCM. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .

TEST TC-25A - INJECTOR #2 CONTROL CIRCUIT (DTC 27)

Note. For connector terminal identification, see CONNECTOR IDENTIFICATION . For wiring diagram, see WIRING DIAGRAMS article in this section.

1. Turn ignition off. Disconnect injector No. 2 connector. Using an external ohmmeter, check resistance between injector terminals. If resistance is not 10-16 ohms, replace injector. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If resistance is 10-16 ohms, turn ignition on.
2. Using DRB, actuate injector No. 2. Using DRB in voltmeter mode, check voltage on injector No. 2 connector, Auto Shutdown (ASD) output circuit Dark Green/Black wire. If voltage is less than 10 volts, repair open Dark Green/Orange wire or Dark Green/Black wire. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If voltage is more than 10 volts, turn ignition off.
3. Disconnect Powertrain Control Module (PCM) connector. Using an external ohmmeter, check resistance of injector No. 2 driver circuit (Tan wire) between injector connector (harness side) and PCM connector terminal No. 15. If resistance is more than 5 ohms, repair open Tan wire. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .
4. If resistance is less than 5 ohms, using DRB in ohmmeter mode, check resistance of PCM terminal No. 15 (Tan wire). If resistance is less than 5 ohms, repair short to ground in Tan wire. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If resistance is more than 5 ohms, replace PCM. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .

TEST TC-26A - INJECTOR #3 CONTROL CIRCUIT (DTC 27)

Note. For connector terminal identification, see CONNECTOR IDENTIFICATION . For wiring diagram, see WIRING DIAGRAMS article in this section.

1. Turn ignition off. Disconnect injector No. 3 connector. Using an external ohmmeter, check resistance between injector terminals. If resistance is not 10-16 ohms, replace injector. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If resistance is 10-16 ohms, turn ignition on.
2. Using DRB, actuate injector No. 3. Using DRB in voltmeter mode, check voltage on injector No. 3 connector, Auto Shutdown (ASD) output circuit Dark Green/Black wire. If voltage is less than 10 volts, repair open Dark Green/Orange wire or Dark Green/Black wire. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If voltage is more than 10 volts, turn ignition off.
3. Disconnect Powertrain Control Module (PCM) connector. Using an external ohmmeter, check resistance of injector No. 3 driver circuit (Yellow/White wire) between injector connector (harness side) and PCM connector terminal No. 14. If resistance is more than 5 ohms, repair open Yellow/White wire. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .
4. If resistance is less than 5 ohms, check resistance of PCM terminal No. 14 (Yellow/White wire) using DRB in ohmmeter mode. If resistance is less than 5 ohms, repair short to ground in Yellow/White wire. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If resistance is more than 5 ohms, replace PCM. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .

TEST TC-27A - INJECTOR #4 CONTROL CIRCUIT (DTC 27)

Note. For connector terminal identification, see CONNECTOR IDENTIFICATION . For wiring diagram, see WIRING DIAGRAMS article in this section.

1. Turn ignition off. Disconnect injector No. 4 connector. Using an external ohmmeter, check resistance between injector terminals. If resistance is not 10-16 ohms, replace injector. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If resistance is 10-16 ohms, turn ignition on.
2. Using DRB, actuate injector No. 4. Using DRB in voltmeter mode, check voltage on injector No. 4 connector, Auto Shutdown (ASD) output circuit Green/Black wire. If voltage is less than 10 volts, repair open Dark Green/Orange wire or Dark Green/Black wire. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If voltage is more than 10 volts, turn ignition off.
3. Disconnect Powertrain Control Module (PCM) connector. Using an external ohmmeter, check resistance of injector No. 4 driver circuit (Light Blue/Brown wire) between injector connector (harness side) and PCM connector terminal No. 13. If resistance is more than 5 ohms, repair open Light Blue/Brown wire. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .
4. If resistance is less than 5 ohms, using DRB in ohmmeter mode, check resistance of PCM terminal No. 13 (Light Blue/Brown wire). If resistance is less than 5 ohms, repair short to ground in Light Blue/Brown wire. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If resistance is more than 5 ohms, replace PCM. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .

TEST TC-28A - INJECTOR #5 CONTROL CIRCUIT (DTC 27)

Note. For connector terminal identification, see CONNECTOR IDENTIFICATION . For wiring diagram, see WIRING DIAGRAMS article in this section.

1. Turn ignition off. Disconnect injector No. 5 connector. Using an external ohmmeter, check resistance between injector terminals. If resistance is not 10-16 ohms, replace injector. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If resistance is 10-16 ohms, turn ignition on.
2. Using DRB, actuate injector No. 5. Using DRB in voltmeter mode, check voltage on injector No. 5 connector, Auto Shutdown (ASD) output circuit Green/Black wire. If voltage is less than 10 volts, repair open Dark Green/Orange wire or Dark Green/Black wire. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If voltage is more than 10 volts, turn ignition off.
3. Disconnect Powertrain Control Module (PCM) connector. Using an external ohmmeter, check resistance of injector No. 5 driver circuit Gray wire between injector connector (harness side) and PCM connector terminal No. 38. If resistance is more than 5 ohms, repair open Pink/Black wire or Gray wire. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .
4. If resistance is less than 5 ohms, using DRB in ohmmeter mode, check resistance of PCM terminal No. 38 Gray wire. If resistance is less than 5 ohms, repair short to ground in Pink/Black wire or Gray wire. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If resistance is more than 5 ohms, replace PCM. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .

TEST TC-29A - INJECTOR #6 CONTROL CIRCUIT (DTC 27)

Note. For connector terminal identification, see CONNECTOR IDENTIFICATION . For wiring diagram, see WIRING DIAGRAMS article in this section.

1. Turn ignition off. Disconnect injector No. 6 connector. Using an external ohmmeter, check resistance between injector terminals. If resistance is not 10-16 ohms, replace injector. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If resistance is 10-16 ohms, turn ignition on.
2. Using DRB, actuate injector No. 6. Using DRB in voltmeter mode, check voltage on injector No. 6 connector, Auto Shutdown (ASD) output circuit Dark Green/Black wire. If voltage is less than 10 volts, repair open Dark Green/Orange wire or Dark Green/Black wire. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If voltage is more than 10 volts, turn ignition off.
3. Disconnect Powertrain Control Module (PCM) connector. Using an external ohmmeter, check resistance of injector No. 6 driver circuit Brown/Yellow between injector connector (harness side) and PCM connector terminal No. 58. If resistance is more than 5 ohms, repair open Light Green/Black wire, Brown/Dark Blue wire or Brown/Yellow wire. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .
4. If resistance is less than 5 ohms, using DRB in ohmmeter mode, check resistance of PCM terminal No. 58 Brown/Yellow wire. If resistance is less than 5 ohms, repair short to ground in Light Green/Black wire, Brown/Dark Blue wire or Brown/Yellow wire. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If resistance is more than 5 ohms, replace PCM. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .

TEST TC-30A - INJECTOR #7 CONTROL CIRCUIT (DTC 27)

Note. For connector terminal identification, see CONNECTOR IDENTIFICATION . For wiring diagram, see WIRING DIAGRAMS article in this section.

1. Turn ignition off. Disconnect injector No. 7 connector. Using an external ohmmeter, check resistance between injector terminals. If resistance is not 10-16 ohms, replace injector. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If resistance is 10-16 ohms, turn ignition on.
2. Using DRB, actuate injector No. 7. Using DRB in voltmeter mode, check voltage on injector No. 7 connector, Auto Shutdown (ASD) output circuit Dark Green/Black wire. If voltage is less than 10 volts, repair open Dark Green/Orange wire or Dark Green/Black wire. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If voltage is more than 10 volts, turn ignition off.
3. Disconnect Powertrain Control Module (PCM) connector. Using an external ohmmeter, check resistance of injector No. 7 driver circuit Dark Blue/White wire between injector connector (harness side) and PCM connector terminal No. 17. If resistance is more than 5 ohms, repair open Dark Blue/Tan wire, or Dark Blue/White wire. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .
4. If resistance is less than 5 ohms, using DRB in ohmmeter mode, check resistance of PCM terminal No. 17 Dark Blue/White wire. If resistance is less than 5 ohms, repair short to ground in Dark Blue/Tan or Dark Blue/White wire. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If resistance is more than 5 ohms, replace PCM. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .

TEST TC-31A - INJECTOR #8 CONTROL CIRCUIT (DTC 27)

Note. For connector terminal identification, see CONNECTOR IDENTIFICATION . For wiring diagram, see WIRING DIAGRAMS article in this section.

1. Turn ignition off. Disconnect injector No. 8 connector. Using an external ohmmeter, check resistance between injector terminals. If resistance is not 10-16 ohms, replace injector. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If resistance is 10-16 ohms, turn ignition on.
2. Using DRB, actuate injector No. 8. Using DRB in voltmeter mode, check voltage on injector No. 8 connector, Auto Shutdown (ASD) output circuit Green/Black wire. If voltage is less than 10 volts, repair open Dark Green/Orange wire or Dark Green/Black wire. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If voltage is more than 10 volts, turn ignition off.
3. Disconnect Powertrain Control Module (PCM) connector. Using an external ohmmeter, check resistance of injector No. 8 driver circuit Dark Blue/Yellow wire between injector connector (harness side) and PCM connector terminal No. 18. If resistance is more than 5 ohms, repair open Dark Blue/Gray wire, Red/Yellow wire, or Dark Blue/Yellow wire. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .
4. If resistance is less than 5 ohms, check resistance of PCM terminal No. 18 Dark Blue/Yellow wire using DRB in ohmmeter mode. If resistance is less than 5 ohms, repair short to ground in Dark Blue/Gray wire, Red/Yellow wire or Dark Blue/Yellow wire. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If resistance is more than 5 ohms, replace PCM. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .

TEST TC-32A - EGR SYSTEM FAILURE (DTC 32)

Note. For connector terminal identification, see CONNECTOR IDENTIFICATION . For wiring diagram, see WIRING DIAGRAMS article in this section.

1. Start engine. Allow engine to idle for at least 2 minutes. Disconnect vacuum supply hose from Exhaust Gas Recirculation (EGR) solenoid. Connect a vacuum gauge to end of disconnected hose. If vacuum gauge indicates less than 10 in. Hg, repair vacuum supply to EGR solenoid. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .
2. If vacuum gauge indicates more than 10 in. Hg, reconnect vacuum hose to EGR solenoid. Disconnect vacuum hose from EGR valve. Connect a vacuum gauge to end of disconnected hose. While observing vacuum gauge, momentarily raise engine speed to more than 2000 RPM.
3. If vacuum gauge indicates less than 5 in. Hg while throttle is open, replace EGR valve assembly. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If vacuum gauge indicates more than 5 in. Hg while throttle is open, remove vacuum gauge.
4. Connect a vacuum pump to EGR valve. With engine idling, slowly apply vacuum to EGR valve. If engine idle becomes rough as vacuum is applied, go to next step. If engine idle does not become rough, remove EGR valve and inspect manifold and EGR backpressure tube for restrictions. If restrictions are present, clean as necessary. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If no restrictions are present, replace EGR valve assembly. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .
5. Turn ignition off. Apply 10 in. Hg vacuum to EGR valve. Observe Vacuum gauge. If vacuum was not held for at least 10 seconds, replace EGR valve assembly. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .
6. If vacuum was held for at least 10 seconds, condition required to set trouble code is not present at this time. EGR SYSTEM FAILURE trouble code sets when Powertrain Control Module (PCM) performs a test of EGR system and monitors oxygen sensor signal for a change. Possible causes are: EGR valve not opening, EGR backpressure tube blocked or EGR passages in manifold blocked. Go to next step.
7. Inspect all related vacuum hoses and connectors. Repair as necessary. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If no problems are found with vacuum hoses and connectors, see INACTIVE TROUBLE CODE CONDITION in this article. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .

TEST TC-33A - EGR SOLENOID CIRCUIT (DTC 32)

Note. For connector terminal identification, see CONNECTOR IDENTIFICATION . For wiring diagram, see WIRING DIAGRAMS article in this section.

1. Using DRB, erase trouble codes. Using DRB, actuate EGR solenoid. Using DRB, read trouble codes. If DRB does not display EGR SOLENOID CIRCUIT, condition required to set trouble code is not present at this time. Go to next step. If DRB displays EGR SOLENOID CIRCUIT, go to step 5).
2. EGR SOLENOID CIRCUIT trouble code sets if EGR solenoid is not in its proper state when monitored by Powertrain Control Module (PCM). Possible causes are: open or shorted EGR solenoid, open EGR solenoid power supply circuit Light Blue wire, open or shorted EGR solenoid ground circuit (Gray/Yellow wire), or failed PCM. Go to next step.
3. Inspect all related wiring and connectors. Repair as necessary. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If no problems are found with wiring and connectors, go to next step.
4. Using DRB, read trouble codes. EGR actuation test should still be running. Wiggle wiring harness from EGR solenoid to PCM. If EGR SOLENOID CIRCUIT trouble code returns, repair wiring harness necessary. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If EGR SOLENOID CIRCUIT trouble code does not return, see INACTIVE TROUBLE CODE CONDITION in this article. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .
5. Turn ignition off. Disconnect EGR solenoid connector. Turn ignition on. Using DRB in voltmeter mode, check voltage on EGR solenoid connector, 12-volt feed circuit Light Blue wire. If voltage is less than 10 volts, repair open Light Blue wire. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .
6. If voltage is more than 10 volts, turn ignition off. Disconnect Powertrain Control Module (PCM) connector. Using external ohmmeter, check resistance of ground circuit (Gray/Yellow wire) between EGR solenoid connector and PCM connector terminal No. 35. If resistance is more than 5 ohms, repair open Gray/Yellow wire. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .
7. If resistance is less than 5 ohms, using DRB in ohmmeter mode, check resistance of PCM connector terminal No. 35 (Gray/Yellow wire). If resistance is less than 5 ohms, repair short to ground in Gray/Yellow wire. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .
8. If resistance is more than 5 ohms, reconnect EGR solenoid connector. Turn ignition on. Using DRB in voltmeter mode, check voltage on PCM connector terminal No. 35 (Gray/Yellow wire). If voltage is less than 10 volts, replace EGR solenoid. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If voltage is more than 10 volts, replace PCM. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .

TEST TC-34A - EVAP SOLENOID CONTROL CIRCUIT (DTC 31)

Note. For connector terminal identification, see CONNECTOR IDENTIFICATION . For wiring diagram, see WIRING DIAGRAMS article in this section.

1. Using DRB, erase trouble codes. Using DRB, actuate Evaporative (EVAP) solenoid. Using DRB, read trouble codes. If DRB does not display EVAP SOLENOID CONTROL CIRCUIT, condition required to set trouble code is not present at this time. Go to next step. If DRB displays EVAP SOLENOID CONTROL CIRCUIT, go to step 5).
2. EVAP SOLENOID CONTROL CIRCUIT trouble code sets if EVAP solenoid is not in its proper state when monitored by Powertrain Control Module (PCM). Possible causes are: open or shorted EVAP solenoid, open EVAP solenoid power supply circuit Light Blue wire open or shorted EVAP solenoid control circuit (Pink/Black wire), or failed PCM. Go to next step.
3. Inspect all related wiring and connectors. Repair as necessary. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If no problems are found with wiring and connectors, go to next step.
4. Using DRB, read trouble codes. EVAP solenoid actuation test should still be running. Wiggle wiring harness from EVAP solenoid to PCM. If EVAP SOLENOID CONTROL CIRCUIT trouble code returns, repair wiring harness. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If EVAP SOLENOID CONTROL CIRCUIT trouble code does not return, see INACTIVE TROUBLE CODE CONDITION in this article. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .
5. Turn ignition off. Disconnect EVAP solenoid connector. Turn ignition on. Using DRB in voltmeter mode, check voltage on EVAP solenoid connector, power supply circuit Light Blue wire. If voltage is less than 10 volts, repair open Dark Blue wire, Light Green/Black wire or Light Blue wire. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .
6. If voltage is more than 10 volts, turn ignition off. Disconnect Powertrain Control Module (PCM) connector. Using an external ohm-meter, check resistance of EVAP solenoid control circuit (Pink/Black wire) between EVAP solenoid connector and PCM connector terminal No. 52. If resistance is less than 5 ohms, repair short to ground in Pink/Black wire. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .
7. If resistance is more than 5 ohms, reconnect EVAP solenoid connector. Turn ignition on. Using DRB in voltmeter mode, check voltage on PCM connector terminal No. 52 (Pink/Black wire). If voltage is less than 10 volts, replace EVAP solenoid. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If voltage is more than 10 volts, replace PCM. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .

TEST TC-35A - TORQUE CONVERTER CLUTCH SOLENOID CIRCUIT (DTC 37)

Note. For connector terminal identification, see CONNECTOR IDENTIFICATION . For wiring diagram, see WIRING DIAGRAMS article in this section.

1. Using DRB, erase trouble codes. On models with overdrive switch on instrument panel, go to TEST TC-35B. Using DRB, actuate Torque Converter Clutch (TCC) relay. If TCC relay does not click, go to step 5). If TCC relay clicks, condition required to set trouble code is not present at this time. Go to next step.
2. TORQUE CONVERTER CLUTCH SOLENOID CIRCUIT trouble code sets if solenoid or relay control circuit (Orange/Black wire) is not in its proper state when monitored by Powertrain Control Module (PCM). Possible causes are: open or shorted solenoid or relay control circuit (Orange/Black wire), open or shorted solenoid or relay coil, and open 12-volt feed circuit (Dark Blue wire) to solenoid or relay. Go to next step.
3. Inspect all related wiring and connectors. Repair as necessary. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If no problems are found with wiring or connectors, go to next step.
4. Using DRB, read trouble codes. TCC actuation test should still be running. Wiggle wiring harness from TCC solenoid relay to PCM. If TCC RELAY CONTROL CIRCUIT trouble code returns, repair wiring harness as necessary. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If TCC RELAY CONTROL CIRCUIT trouble code does not return, test is complete. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .
5. Disconnect TCC relay connector. Using DRB in voltmeter mode, check voltage on TCC solenoid connector terminal "A", ignition feed circuit (Dark Blue wire).
6. If voltage is less than 10 volts, repair open Dark Blue wire. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If voltage is more than 10 volts, turn ignition off. Disconnect Powertrain Control Module (PCM) connector. Using DRB in ohmmeter mode, check resistance of PCM connector terminal No. 54, TCC solenoid control circuit (Orange/Black wire).
7. If resistance is less than 5 ohms, repair short to ground in Orange/Black wire. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If resistance is more than 5 ohms, go to next step.
8. Using an external ohmmeter, check resistance of TCC solenoid control circuit (Orange/Black wire) between PCM connector terminal No. 54 and TCC solenoid connector. If resistance is more than 5 ohms, repair open Orange/Black wire. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If resistance is less than 5 ohms, reconnect TCC solenoid connector. Turn ignition on.
9. Using DRB in voltmeter mode, check voltage on PCM connector terminal No. 54, TCC solenoid control circuit (Orange/Black wire). If voltage is more than 10 volts, replace PCM. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If resistance is less than 10 volts, replace TCC relay. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .

TEST TC-35B - TORQUE CONVERTER CLUTCH SOLENOID CIRCUIT (DTC 37)

Note. For connector terminal identification, see CONNECTOR IDENTIFICATION . For wiring diagram, see WIRING DIAGRAMS article in this section.

1. Using DRB, actuate Torque Converter Clutch (TCC) solenoid. Wait 10 seconds. Using DRB, read trouble codes. If TORQUE CONVERTER CLUTCH SOLENOID CIRCUIT trouble code does not return, go to next step. If TORQUE CONVERTER CLUTCH SOLENOID CIRCUIT trouble code returns, go to step 4).
2. TCC actuation test should still be running. Wiggle wiring harness from TCC solenoid relay to PCM. Using DRB, read trouble codes. If TCC RELAY CONTROL CIRCUIT trouble code returns, repair wiring harness as necessary. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If TCC RELAY CONTROL CIRCUIT trouble code does not return, condition required to set trouble code is not present at this time.
3. TORQUE CONVERTER CLUTCH SOLENOID CIRCUIT trouble code sets if solenoid or relay control circuit Violet/Yellow wire is not in its proper state when monitored by PCM. Possible causes are: open or shorted solenoid or relay control circuit, open or shorted solenoid or relay coil, and open 12-volt feed circuit Light Blue wire to solenoid or relay. Test is complete. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .
4. Disconnect transmission solenoid connector. Using DRB in voltmeter mode, check voltage on transmission solenoid connector, ignition feed circuit Light Blue wire. If voltage is less than 10 volts, repair Dark Blue wire, Light Green/Black wire or Light Blue wire as necessary. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If voltage is more than 10 volts, turn ignition off.
5. Disconnect Powertrain Control Module (PCM) connector. Using DRB in ohmmeter mode, check resistance of PCM connector terminal No. 54, TCC solenoid control circuit Violet/Yellow wire. If resistance is less than 5 ohms, repair short to ground in Orange/Black wire or Violet/Yellow wire. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If resistance is more than 5 ohms, go to next step.
6. Using an external ohmmeter, check resistance of TCC solenoid control circuit Violet/Yellow wire between PCM connector terminal No. 54 and transmission solenoid connector. If resistance is more than 5 ohms, repair open Orange/Black wire or Violet/Yellow wire. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If resistance is less than 5 ohms, reconnect transmission solenoid connector. Turn ignition on.
7. Using DRB in voltmeter mode, check voltage on PCM connector terminal No. 54, TCC solenoid control circuit Violet/Yellow wire. If voltage is more than 10 volts, replace PCM. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If resistance is less than 10 volts, replace TCC solenoid. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .

TEST TC-36A - TRANS OVERDRIVE SOLENOID CIRCUIT (DTC 45)

Note. For connector terminal identification, see CONNECTOR IDENTIFICATION . For wiring diagram, see WIRING DIAGRAMS article in this section.

1. Using DRB, erase trouble codes and actuate Overdrive (OD) solenoid. Wait 10 seconds. Using DRB, read trouble codes. If TRANS OVERDRIVE SOLENOID CIRCUIT trouble code does not return, go to next step. If TRANS OVERDRIVE SOLENOID CIRCUIT trouble code returns, go to step 4).
2. OD solenoid actuation test should still be running. While monitoring DRB, wiggle wiring harness from OD solenoid connector to Powertrain Control Module (PCM). If TRANS OVERDRIVE SOLENOID CIRCUIT trouble code does not return, condition required to set trouble code is not present at this time. Go to next step. If TRANS OVERDRIVE SOLENOID CIRCUIT trouble code returns, go to step 4).
3. TRANS OVERDRIVE SOLENOID CIRCUIT trouble codes sets if OD solenoid control circuit Brown/Light Green wire is not in its proper state when monitored by PCM. Possible causes are: open or shorted OD control circuit, open or shorted OD solenoid coil, or open OD solenoid feed circuit Light Blue wire. Test is complete. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .
4. Disconnect transmission solenoid connector. Using DRB in voltmeter mode, check voltage on transmission solenoid connector, ignition feed circuit Light Blue wire. If voltage is less than 10 volts, repair open Dark Blue wire, Light Green/Black wire or Light Blue wire. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If voltage is more than 10 volts, turn ignition off.
5. Disconnect Powertrain Control Module (PCM). Using DRB in ohm-meter mode, check resistance of PCM connector terminal No. 55, OD solenoid control circuit Brown/Light Green wire. If resistance is less than 5 ohms, repair short to ground in Orange/White wire, Orange/Light Green wire, Brown wire or Brown/Light Green wire. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If resistance is more than 5 ohms, go to next step.
6. Using an external ohmmeter, check resistance of OD solenoid control circuit Brown/Light Green wire between PCM connector terminal No. 55 and transmission solenoid connector. If resistance is more than 5 ohms, repair open Orange/White wire, Orange/Light Green wire, Brown wire or Brown/Light Green wire. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If resistance is less than 5 ohms, reconnect transmission solenoid connector.
7. Turn ignition on. Using DRB in voltmeter mode, check voltage on PCM connector terminal No. 55, overdrive solenoid control circuit Brown/Light Green wire. If voltage is more than 10 volts, replace PCM. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If voltage is less than 10 volts, replace OD solenoid. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .

TEST TC-37A - A/C CLUTCH RELAY CIRCUIT (DTC 33)

Note. For connector terminal identification, see CONNECTOR IDENTIFICATION . For wiring diagram, see WIRING DIAGRAMS article in this section.

Scheme 38

1. Using DRB, actuate A/C clutch relay. If A/C clutch relay is clicking, go to next step. If A/C clutch relay is not clicking, go to step 5).
2. Condition required to set trouble code is not present at this time. A/C CLUTCH RELAY CIRCUIT trouble code sets if A/C clutch relay control circuit Dark Blue/Red wire is not in its proper state when monitored by Powertrain Control Module (PCM). Possible causes are: open or short in A/C clutch relay coil windings, open or short in A/C clutch relay control circuit Dark Blue/Red wire, open or short in A/C clutch relay ignition feed circuit Yellow/Dark Green wire, or failed driver in PCM. Go to next step.
3. Inspect all related wiring and connectors. Repair as necessary. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification). If no problems are found with wiring and connectors, go to next step.
4. While still actuating A/C clutch relay, wiggle wiring harness from A/C clutch relay to PCM. If wiggling interrupts A/C clutch relay clicking, repair wiring harness as necessary. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification). If wiggling does not interrupt A/C clutch relay clicking, see INACTIVE TROUBLE CODE CONDITION in this article. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification).
5. Remove A/C clutch relay. Install a known-good A/C clutch relay. If known-good A/C clutch relay is clicking, replace original A/C clutch relay. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification). If known-good A/C clutch relay is not clicking, remove known-good A/C clutch relay.
6. Using DRB in voltmeter mode, check voltage on A/C clutch relay connector, ignition feed circuit Yellow/Dark Green wire. If voltage is less than 10 volts, repair open Dark Blue wire or Yellow/Dark Green wire. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification).
7. If voltage is more than 10 volts, using an external ohmmeter, check resistance across A/C clutch relay terminals. (Scheme 38) If resistance is more than 100 ohms, replace A/C clutch relay. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification). If resistance is less than 100 ohms, go to next step. (Scheme 38): Testing Relay (TC-37A)
8. Turn ignition off. Disconnect Powertrain Control Module (PCM) connector. Using DRB in ohmmeter mode, check resistance of A/C clutch relay connector, control circuit Dark Blue/Red wire. If resistance is less than 5 ohms, repair short to ground in Dark Blue/Orange wire or Dark Blue/Red wire. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification).
9. If resistance is more than 5 ohms, check resistance of control circuit Dark Blue/Red wire between A/C clutch relay connector and PCM connector terminal No. 34 using an external ohmmeter. If resistance is more than 5 ohms, repair open Dark Blue/Orange wire or Dark Blue/Red wire. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification). If resistance is less than 5 ohms, replace PCM. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification).

TEST TC-38A - AUTO SHUTDOWN RELAY CONTROL CIRCUIT (DTC 42)

Note. For connector terminal identification, see CONNECTOR IDENTIFICATION . For wiring diagram, see WIRING DIAGRAMS article in this section.

1. Using DRB, actuate Auto Shutdown (ASD) relay. If ASD relay is not clicking, go to step 5). If ASD relay is clicking, condition required to set trouble code is not present at this time.
2. AUTO SHUTDOWN RELAY CONTROL CIRCUIT trouble code sets if ASD relay and fuel pump relay control circuit Pink wire are not in proper state when monitored by Powertrain Control Module (PCM) during cranking. Possible causes are: open or short in ASD relay and fuel pump relay control circuits, open or short in ASD relay ignition feed circuit Light Blue/Red wire, or failed driver in PCM. Go to next step.
3. Inspect all related wiring and connectors. Repair as necessary. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification). If no problems are found with wiring and connectors, go to next step.
4. While still actuating ASD relay, wiggle wiring harness from ASD relay to PCM. Using DRB, read trouble codes. If AUTO SHUTDOWN RELAY CONTROL CIRCUIT trouble code returns, repair wiring harness as necessary. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification). If AUTO SHUTDOWN RELAY CONTROL CIRCUIT trouble code does not return, system is functioning properly. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification).
5. Remove ASD relay. Install a known-good ASD relay. If known-good ASD relay is clicking, replace original ASD relay. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification). If known-good ASD relay is not clicking, remove known-good ASD relay.
6. DRB should still be actuating ASD relay. Using DRB in voltmeter mode, check voltage on ASD relay connector, ignition feed circuit Light Blue/Red wire. If voltage is less than 10 volts, repair open Dark Blue wire or Light Blue/Red wire. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification).
7. If voltage is more than 10 volts, using an external ohmmeter, check resistance across ASD relay terminals. (Scheme 38) If resistance is more than 100 ohms, replace ASD relay. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification). If resistance is less than 100 ohms, go to next step.
8. Turn ignition off. Disconnect Powertrain Control Module (PCM) connector. Using DRB in ohmmeter mode, check resistance of ASD relay connector, control circuit Dark Green/Black wire. If resistance is less than 5 ohms, repair short to ground in Dark Green/Orange wire or Dark Green/Black wire. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification).
9. If resistance is more than 5 ohms, using an external ohmmeter, check resistance of control circuit Dark Green/Black wire between ASD relay connector and PCM connector terminal No. 57. If resistance is more than 5 ohms, repair open Dark Green/Orange wire or Dark Green/Black wire. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification). If resistance is less than 5 ohms, replace PCM. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification).

TEST TC-39A - NO ASD RELAY VOLT SENSE AT PCM (DTC 42)

Note. For connector terminal identification, see CONNECTOR IDENTIFICATION . For wiring diagram, see WIRING DIAGRAMS article in this section.

1. If DRB also displays AUTO SHUTDOWN RELAY CONTROL CIRCUIT is also set, go to TEST TC-38A. If DRB does not display AUTO SHUTDOWN RELAY CONTROL CIRCUIT, attempt to start engine. Allow engine to idle. If engine starts and NO ASD RELAY OUTPUT VOLTAGE AT PCM trouble code does not reset, go to next step. If NO ASD RELAY OUTPUT VOLTAGE AT PCM trouble code resets, and/or engine did not start, go to step 5).
2. Condition required to set trouble code is not present at this time. NO ASD RELAY OUTPUT VOLTAGE AT PCM trouble code sets if no voltage is sensed at Powertrain Control Module (PCM) when Auto Shutdown (ASD) relay is energized. Possible causes are: open or short in ASD relay and fuel pump relay control circuits Pink wire, open or short in ASD relay ignition feed circuit Light Blue/Red wire, or failed driver in Powertrain Control Module (PCM). Go to next step.
3. Inspect all related wiring and connectors, and repair as necessary. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If no problems were found with wiring and connectors, go to next step.
4. While engine is running, wiggle wiring harness from ASD relay to Powertrain Control Module (PCM). Using DRB, read trouble codes. If NO ASD RELAY OUTPUT VOLTAGE AT PCM trouble code returned, repair wiring harness as necessary. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If NO ASD RELAY OUTPUT VOLTAGE AT PCM trouble code did not return, see INACTIVE TROUBLE CODE CONDITION in this article. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .
5. If engine started, turn ignition off and go to step 7). If engine did not start, disconnect Auto Shutdown (ASD) relay. Using DRB in voltmeter mode, check voltage on ASD relay connector, battery feed circuit Red wire. If voltage is less than 10 volts, repair open in Red wire, Red/White wire or Gray/White wire. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .
6. If voltage is more than 10 volts, install a known-good ASD relay. Attempt to start engine. If engine started, replace ASD relay. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If engine did not start, turn ignition off.
7. Disconnect Powertrain Control Module (PCM) connector. Using an external ohmmeter, check resistance of ASD relay output circuit Green/Black wire between ASD relay connector and PCM connector terminal No. 57. If resistance is more than 5 ohms, repair open in Dark Green/Orange wire or Dark green/Black wire. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If resistance is less than 5 ohms, replace PCM. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .

TEST TC-40A - TRANS TEMP SENSOR VOLTAGE TOO LOW (DTC 37)

Note. For connector terminal identification, see CONNECTOR IDENTIFICATION . For wiring diagram, see WIRING DIAGRAMS article in this section.

1. Using DRB, read Transmission Temperature (TRANS TEMP) SENSOR voltage. If voltage is less than .5 volt, go to step 4). If voltage is more than .5 volt, wiggle transmission temperature sensor connector and wiring harness while monitoring DRB display. If sensor voltage changed, repair connector or wiring harness as necessary. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .
2. If sensor voltage did not change, condition required to set trouble code is not present at this time. TRANS TEMP SENSOR VOLTAGE TOO LOW trouble code sets if Powertrain Control Module (PCM) sees less than .5 volt at PCM terminal No. 42 (Violet wire) with ignition on. Possible causes are: short in transmission temperature sensor signal circuit (Violet wire), transmission temperature sensor shorted internally or failed PCM. Go to next step.
3. Inspect all related wiring and connectors, and repair as necessary. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If no problems were found with wiring and connectors, see INACTIVE TROUBLE CODE CONDITION in this article. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .
4. Disconnect transmission temperature sensor connector. Using DRB, read TRANS TEMP SENSOR voltage. If voltage is more than 4 volts, replace transmission temperature sensor. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If voltage is less than 4 volts, turn ignition off.
5. Disconnect Powertrain Control Module (PCM) connector. Using DRB in ohmmeter mode, check resistance of transmission temperature sensor signal circuit (Violet wire). If resistance is less than 5 ohms, repair short to ground in Violet wire. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If resistance is more than 5 ohms, replace PCM. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .

TEST TC-41A - TRANS TEMP SENSOR VOLTAGE HIGH (DTC 37)

Note. For connector terminal identification, see CONNECTOR IDENTIFICATION . For wiring diagram, see WIRING DIAGRAMS article in this section.

1. Using DRB, read TRANS TEMP SENSOR voltage. If voltage is more than 4.9 volts, go to step 4). If voltage is less than 4.9 volts, wiggle transmission temperature sensor connector and wiring harness while monitoring DRB display. If sensor voltage changed, repair connector or wiring harness as necessary. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .
2. If sensor voltage did not change, condition required to set trouble code is not present at this time. TRANS TEMP SENSOR VOLTAGE TOO HIGH trouble code sets if Powertrain Control Module (PCM) sees more than 4.9 volts at PCM terminal No. 42 (Violet wire) with ignition on. Possible causes are: open in transmission temperature sensor signal circuit (Violet wire), transmission temperature sensor open internally, open sensor ground circuit (Black/Light Blue wire) or failed PCM. Go to next step.
3. Inspect all related wiring and connectors, and repair as necessary. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If no problems were found with wiring and connectors, see INACTIVE TROUBLE CODE CONDITION in this article. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .
4. Disconnect transmission temperature sensor connector. Connect a jumper wire between transmission temperature sensor connector, signal circuit (Violet wire) and sensor ground circuit (Black/Light Blue wire). Using DRB, read TRANS TEMP SENSOR voltage. If voltage is less than one volt, replace transmission temperature sensor. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .
5. If voltage is more than one volt, move jumper wire from transmission temperature sensor connector, ground circuit (Black/Light Blue wire) to an engine ground. Using DRB, read TRANS TEMP SENSOR voltage. If voltage is less than one volt, repair open Black/Light Blue wire.
6. If voltage is more than one volt, turn ignition off. Disconnect Powertrain Control Module (PCM) connector. Using an external ohm-meter, check resistance of transmission temperature sensor signal circuit (Violet wire) between transmission temperature sensor connector and PCM terminal No. 42. If resistance is less than 5 ohms, replace PCM. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If resistance is more than 5 ohms, repair open Violet wire. Perform TEST VER-2

TEST TC-42A - PCM FAILURE SRI MILE NOT STORED OR PCM FAILURE EEPROM WRITE DENIED (DTC 62 or 63)

Note. For connector terminal identification, see CONNECTOR IDENTIFICATION . For wiring diagram, see WIRING DIAGRAMS article in this section.

1. Turn ignition on. Using DRB, perform SRI memory test. If DRB displays WRITE FAILURE, replace Powertrain Control Module (PCM). Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If DRB does not display WRITE FAILURE, go to next step.
2. If DRB displays WRITE REFUSED, go to step 4). If DRB does not display WRITE REFUSED, go to next step.
3. If DRB displays SRI MILEAGE INVALID, update mileage and retest SRI memory. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If DRB does not display SRI MILEAGE INVALID, compare SRI mileage stored with instrument panel odometer. If mileage is same, retest SRI memory. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If mileage is not same, update mileage and retest SRI memory. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .
4. When DRB displays WRITE REFUSED, PCM is busy. Using DRB, perform SRI memory test. Retest SRI memory 2 more times if necessary. If DRB displays WRITE REFUSED, replace PCM. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If DRB does not display WRITE REFUSED, vehicle is functioning properly. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .

No Trouble Code Complete Test

Check Tech Service Bulletins (TSBs) for any pertinent information. If a TSB exists, perform corrective action. If TSB does not exist or if driveability problem still exists, perform tests NTC-2A through NTC-15A in sequence until driveability problem is found. See NO TROUBLE CODE TEST MENU table.

NO TROUBLE CODE TEST MENU

No Trouble Code Quick Individual Test

If it is suspected that any item listed in NO TROUBLE CODE TEST MENU table is cause of a vehicle's driveability problem, perform associated test individually. Return to NO TROUBLE CODE TEST MENU table if driveability problem still exists, or perform NO TROUBLE CODE COMPLETE TEST.

No Trouble Code Quick Symptom Test

Symptom checks cannot be used properly unless driveability problem characteristic actually happens while vehicle is being tested. To reduce diagnostic time, ensure that TEST TC-1A is reviewed before attempting to diagnose a symptom.

Select symptom that most accurately describes vehicle's driveability problem and then perform test pertaining to this symptom. Perform each test in sequence until problem is found. See NO TROUBLE CODE QUICK SYMPTOM TEST MENU table.

NO TROUBLE CODE QUICK SYMPTOM TEST MENU

TEST NTC-2A - CHECKING SECONDARY IGNITION & TIMING

1. Turn engine off. Connect engine analyzer to engine. Start engine, and let it idle. If engine will not idle, maintain a constant RPM above idle. Set scope to read display or parade pattern. Follow equipment manufacturer's procedure for pattern analysis.
2. If secondary ignition pattern is not okay, repair indicated component in secondary ignition system. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If secondary ignition pattern is okay, disconnect any spark plug wire. Observe secondary kilovolt line.
3. If open circuit secondary voltage is not at least 25 kilovolts, replace electronic ignition coil. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If open circuit secondary voltage is at least 25 kilovolts, reinstall spark plug wire.
4. Ensure engine temperature is more than 180°F (82°C) before proceeding. Using DRB, read total spark advance. Increase engine speed to 2000 RPM. If spark advance does not change with increase in RPM, replace Powertrain Control Module (PCM). Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If spark advance changes with increase in RPM, ignition timing is functioning properly. Test is complete.

TEST NTC-3A - CHECKING FUEL PRESSURE

1. Release fuel pressure. Connect fuel pressure gauge to fuel rail. Turn ignition on. Using DRB, actuate fuel system. If fuel pressure is 34-45 psi (2.5-3.3 kg/cm 2 ), fuel pressure is normal. Test is complete. If fuel pressure is not 34-45 psi (2.5-3.3 kg/cm 2 ), record fuel pressure reading.
2. If pressure is more than 45 psi (3.3 kg/cm 2 ) on 5.2L ZJ body, go to TEST NTC-3B. Stop fuel system actuation if pressure is not more than 45 psi (3.3 kg/cm 2 ). Turn ignition off.
3. Inspect fuel lines for kinked or restricted lines. Repair fuel lines as necessary. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If no kinked or restricted lines exist on 5.2L ZJ body, release fuel pressure.
4. Remove fuel pressure gauge from fuel rail. Install fuel pressure gauge between fuel tank and fuel filter. Turn ignition on. Using DRB, actuate fuel system. If fuel pressure is at least 10 psi (.7 kg/cm 2 ) more than previously recorded pressure, replace fuel filter. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . CAUTION: DO NOT allow fuel pressure to exceed 60 psi (4.2 kg/cm 2 ) when squeezing fuel return hose.
5. If fuel pressure is not at least 10 psi (.7 kg/cm 2 ) more than previous reading, gently squeeze fuel return hose while observing fuel pressure gauge. Ensure fuel pressure does not exceed 60 psi (4.2 kg/cm 2 ). If fuel pressure increases, replace fuel pressure regulator. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If fuel pressure does not increase, replace fuel pump and sock assembly. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .

TEST NTC-3B - CHECKING FUEL PRESSURE

1. Using DRB, stop fuel system actuation. Release fuel pressure. Ensure fuel tank is at least 1/4 full before performing following test. Install fuel pressure gauge and adapter between fuel tank and filter at rear of vehicle.
2. Remove fuel return line from fuel pump at fuel tank. Connect Fuel Pressure Test Adapter (6541) to fuel return line. Place other end of adapter hose into an approved 2-gallon gasoline can. Turn ignition on.
3. Using DRB, actuate fuel system. Observe fuel pressure gauge. If fuel pressure is 34-45 psi (2.5-3.3 kg/cm 2 ), repair fuel return line for a restriction at fuel tank. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .
4. If fuel pressure is not 34-45 psi (2.5-3.3 kg/cm 2 ), stop fuel system actuation. Release fuel pressure. Reconnect fuel return line to fuel tank. Disconnect fuel return line from fuel rail.
5. Attach Fuel Pressure Test Adapter (6541) to fuel return line nipple at fuel rail. Place other end of adapter hose into an approved 2-gallon gasoline can. Turn ignition on. Using DRB, actuate fuel system. Observe fuel pressure gauge.
6. If fuel pressure is 34-45 psi (2.5-3.3 kg/cm 2 ), repair fuel return line for a restriction to fuel tank. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If fuel pressure is not 34-45 psi (2.5-3.3 kg/cm 2 ), inspect fuel pressure damper line for any restrictions. Replace fuel pressure damper line if necessary. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If no restrictions exist, replace fuel pressure regulator. Perform TEST VER-2.

TEST NTC-4A - CHECKING COOLANT SENSOR CALIBRATION

1. Start engine. Using DRB, read Engine Coolant Temperature (ECT) sensor value. If ECT sensor temperature is more than 180°F (82°C), stop engine. Allow engine coolant to cool to 150°F (66°C). Start engine. Allow engine to reach normal operating temperature of 180°F (82°C). If ECT sensor value does not increase smoothly, repair cooling system as necessary and replace ECT sensor. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If ECT sensor value increases smoothly, go to next step.
2. If ECT sensor value did not reach 180°F (82°C) or more, repair cooling system as necessary and replace ECT sensor. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If ECT sensor value reached 180°F (82°C) or more, system is functioning properly. Test is complete.

TEST NTC-5A - CHECKING TPS CALIBRATION

1. Turn engine off. Turn ignition on. Using DRB, read Throttle Position Sensor (TPS) voltage. Ensure throttle is fully closed and against throttle stop. If voltage is not 1.5 volts or less with throttle closed, replace TPS. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .
2. If voltage is 1.5 volts or less with throttle closed, monitor voltage while slowly opening throttle wide open. If voltage change is not smooth, replace TPS. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If voltage change is smooth, go to next step.
3. If maximum voltage is not at least 3.4 volts at wide open throttle, replace TPS. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If maximum voltage is at least 3.4 volts at wide open throttle, TPS is functioning properly. Test is complete.

TEST NTC-6A - CHECKING MAP SENSOR CALIBRATION

1. Turn engine off. Install vacuum "T" in Manifold Absolute Pressure (MAP) sensor vacuum hose. Install vacuum gauge. Start engine, and let it idle. If engine will not idle, maintain a constant RPM above idle.
2. Using DRB, read MAP sensor value. If reading is within one in. Hg of vacuum gauge reading, MAP sensor is functioning properly. Test is complete. If reading is not within one in. Hg of vacuum gauge reading, replace MAP sensor. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .

TEST NTC-7A - CHECKING OXYGEN (O2) SENSOR SWITCHING

1. On 5.9L Heavy Duty (HD) models with dual O2 sensors, go to TEST NTC-7C. On all other models, allow engine to reach normal operating temperature. Using DRB, read O2 sensor state. If O2 sensor state is switching, system is functioning properly. Test is complete. If O2 sensor state is not switching, check if O2 sensor is locked on lean. If O2 sensor is locked on lean, go to TEST NTC-7B. If O2 sensor is not locked on lean, turn engine off.
2. Release fuel pressure. Install a fuel pressure gauge in fuel supply line. Turn ignition on. Using DRB, actuate fuel system. Allow fuel pressure to stabilize. Stop fuel system actuation. Monitor fuel gauge for one minute. If fuel pressure drops more than 10 psi (.7 kg/cm 2 ), replace leaking injector(s) or "O" ring(s) as necessary. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .
3. If fuel pressure does not drop more than 10 psi (.7 kg/cm 2 ), inspect air filter and air inlet ducts for restrictions. Clean restricted air inlet system as necessary. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If no restrictions exist, go to «TEST NTC-15A»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ntc-15a-no-trouble-code) .

TEST NTC-7B - CHECKING OXYGEN (O2) SENSOR SWITCHING

Note. For connector terminal identification, see CONNECTOR IDENTIFICATION . For wiring diagram, see WIRING DIAGRAMS article in this section.

1. Allow engine to idle. Inspect engine for vacuum leaks. Repair vacuum leaks as necessary. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If no vacuum leaks exist, read O2 sensor signal voltage using DRB.
2. If voltage is more than 0.1 volt, go to step 4). If voltage is less than 0.1 volt, turn ignition off. Disconnect O2 sensor connector. Disconnect Powertrain Control Module (PCM) connector. Using DRB in ohmmeter mode, check resistance of O2 sensor connector (harness side), signal circuit Black/Orange wire.
3. If resistance is less than 5 ohms, repair short to ground in Dark Green/White wire or Black/Orange wire. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If resistance is more than 5 ohms, replace O2 sensor. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .
4. Turn engine off. Replace O2 sensor. Turn ignition on. Using DRB, reset adaptive fuel memory. Start engine. Allow engine to reach normal operating temperature.
5. Using DRB, read O2 sensor state. If O2 sensor state is switching, repair is complete. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If O2 sensor state is not switching, go to «TEST NTC-15A»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ntc-15a-no-trouble-code) .

TEST NTC-8A - CHECKING IDLE AIR CONTROL MOTOR

Note. For connector terminal identification, see CONNECTOR IDENTIFICATION . For wiring diagram, see WIRING DIAGRAMS article in this section.

1. Using DRB, set engine speed to 1100 RPM. If engine speed set at 1050-1150 RPM, idle speed motor is operating properly. Test is complete. If engine speed did not set at 1050-1150 RPM, return engine to normal idle speed. Disconnect Idle Air Control (IAC) motor connector.
2. Using DRB in voltmeter mode, check voltage on IAC motor connector, driver No. 1 circuit (Brown/White wire) while momentarily opening and closing throttle. If voltage is less than one volt, go to TEST NTC-8B. If voltage is more than one volt, go to next step.
3. Using DRB, check voltage on IAC motor connector, driver No. 2 circuit Violet/Black wire while momentarily opening and closing throttle. If voltage is less than one volt, go to «TEST NTC-8B»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ntc-8b-checking-idle-air) . If voltage is more than one volt, go to next step.
4. Using DRB, check voltage on IAC motor connector, driver No. 3 circuit Yellow/Black wire while momentarily opening and closing throttle. If voltage is less than one volt, go to «TEST NTC-8B»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ntc-8b-checking-idle-air) . If voltage is more than one volt, go to next step.
5. Using DRB, check voltage on IAC motor connector, driver No. 4 circuit Gray/Red wire while momentarily opening and closing throttle. If voltage is less than one volt, go to «TEST NTC-8B»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ntc-8b-checking-idle-air) . If voltage is more than one volt, go to next step.
6. Check engine for vacuum leaks. Repair as required. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If no vacuum leaks are observed, remove IAC motor. Ensure IAC motor electrical connector is connected. Using DRB, actuate IAC motor. If IAC motor pintle does not extend and retract, replace IAC motor. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If IAC motor pintle extends and retracts, reinstall IAC motor. System is functioning okay. Test is complete.

TEST NTC-8B - CHECKING IDLE AIR CONTROL MOTOR

Note. For connector terminal identification, see CONNECTOR IDENTIFICATION . For wiring diagram, see WIRING DIAGRAMS article in this section.

Turn engine off. Disconnect Powertrain Control Module (PCM) connector. Using an external ohmmeter, check resistance of each wire between Idle Air Control (IAC) motor connector and PCM connector. See PCM TERMINAL IDENTIFICATION table. If resistance for any wire is more than 5 ohms, repair open on appropriate wire. Perform TEST VER-2 . If resistance for all wires is less than 5 ohms, replace PCM. Perform TEST VER-2 .

PCM TERMINAL IDENTIFICATION

TEST NTC-9A - CHECKING SOLENOID OPERATIONS

Note. For connector terminal identification, see CONNECTOR IDENTIFICATION . For wiring diagram, see WIRING DIAGRAMS article in this section.

1. Using DRB, actuate purge solenoid. While touching top of purge solenoid, feel for operation. If purge solenoid does not operate, replace purge solenoid. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .
2. If purge solenoid operates, actuate EGR solenoid. While touching top of EGR solenoid, feel for operation. If EGR solenoid does not operate, replace EGR solenoid. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If EGR solenoid operates, test is complete.

TEST NTC-10A - CHECKING PARK/NEUTRAL SWITCH

Note. For connector terminal identification, see CONNECTOR IDENTIFICATION . For wiring diagram, see WIRING DIAGRAMS article in this section.

1. Using DRB, read park/neutral switch input state. While watching DRB display, move gear selector in and out of PARK and REVERSE positions. If DRB displays P/N and D/R, system is functioning properly. Test is complete.
2. If DRB does not display P/N and D/R, turn ignition off. Place gear selector in PARK position. Disconnect Powertrain Control Module (PCM) connector. Using DRB in ohmmeter mode, check resistance of PCM connector terminal No. 30, park/neutral switch sense circuit Black/White wire. Observe DRB display while moving gear selector in and out of PARK and REVERSE positions.
3. If display switches from less than 5 ohms to more than 5 ohms, replace PCM. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If display does not switch from less than 5 ohms to more than 5 ohms, check if display always stays less than 5 ohms. If display always stays less than 5 ohms, repair short to ground in Black/Orange wire, Brown/Yellow wire or Black/White wire. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If display does not always stay less than 5 ohms, go to next step.
4. Disconnect park/neutral switch connector. Using external ohmmeter, check resistance of sense circuit Black/White wire between park/neutral switch connector and PCM connector terminal No. 30. If resistance is less than 10 ohms, replace the park/neutral switch. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If resistance is more than 10 ohms, repair the open Black/Orange wire, Brown/Yellow wire or Black/White wire. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .

TEST NTC-11A - CHECKING PCM GROUNDS & POWER CIRCUITS

Note. For connector terminal identification, see CONNECTOR IDENTIFICATION . For wiring diagram, see WIRING DIAGRAMS article in this section.

1. Turn ignition off. Disconnect Powertrain Control Module (PCM) connector. Using DRB in ohmmeter mode, check resistance of PCM connector terminal No. 5, signal ground circuit Black/Tan wire. If resistance is more than 5 ohms, repair open Black/White wire or Black/Tan wire. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If resistance is less than 5 ohms, go to next step.
2. Using DRB, check resistance of PCM connector terminal No. 11, power ground circuit (Black/Tan wire). If resistance is more than 5 ohms, repair open Black/Tan wire. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If resistance is less than 5 ohms, go to next step.
3. Using DRB, check resistance of PCM connector terminal No. 12, power ground circuit (Black/Tan wire). If resistance is more than 5 ohms, repair open Black/Tan wire. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If resistance is less than 5 ohms, go to next step.
4. Turn ignition on. Using DRB in voltmeter mode, check voltage on PCM connector terminal No. 9, ignition 12-volt feed circuit (Dark Blue wire). If voltage is less than 10 volts, repair open Dark Blue wire. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If voltage is more than 10 volts, turn ignition off. Reconnect PCM connector. PCM grounds and power circuits are okay. Test is complete.

TEST NTC-12A - CHECKING EGR SYSTEM

1. Using DRB, read module information. If module information indicates vehicle is equipped with California emissions, this test does not apply, however this test can still be performed. Go to next step. If module information indicates vehicle is not equipped with California emissions, go to next step.
2. Disconnect vacuum hose from EGR solenoid. Connect vacuum gauge to disconnected vacuum hose. Start engine. If vacuum is more than 10 in. Hg at idle, go to step 4).
3. If vacuum is less than 10 in. Hg at idle, disconnect EGR vacuum signal hose at intake manifold. Connect a vacuum gauge to intake nipple. Read vacuum gauge at idle. If vacuum is more than 10 in. Hg at idle, repair restriction or leak in vacuum hose to EGR solenoid. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If Vacuum is less than 10 in. Hg at idle, repair plugged vacuum nipple at intake manifold. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .
4. Disconnect vacuum gauge. Reconnect vacuum hose to EGR solenoid. Disconnect vacuum hose from EGR valve. Connect vacuum gauge to disconnected hose. While observing vacuum gauge, momentarily snap throttle open. If vacuum is less than 5 in. Hg, replace EGR valve assembly. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If vacuum is more than 5 in. Hg, go to next step.
5. Turn ignition off. Disconnect hose to EGR valve backpressure signal tube. Adjust a shop air hose to 20 psi (1.4 kg/cm 2 ). Connect shop air to nipple on base of EGR valve. Listen for a tone change while opening and closing throttle.
6. If tone changes, replace EGR valve. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If tone does not change, remove vacuum gauge. Cap open nipple at EGR valve base. Connect hand vacuum pump to EGR valve. Listen for engine RPM change while slowly applying vacuum to EGR valve. If engine RPM does not change, replace EGR valve. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .
7. If engine RPM changes, turn ignition off. Apply 10 in. Hg and hold for 30 seconds. If vacuum holds for 30 seconds, EGR system is functioning properly. Test is complete. If vacuum does not hold for 30 seconds, replace EGR valve. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .

TEST NTC-13A - CHECKING ENGINE VACUUM

Connect a vacuum gauge to engine manifold vacuum source. Start engine. Allow engine to idle. Normal vacuum reading will vary depending on altitude. Observe vacuum gauge at idle. If vacuum gauge reading is steady 13-22 in. Hg, engine vacuum is normal. Test is complete. If vacuum gauge reading is not steady 13-22 in. Hg, perform TEST NTC-15A .

TEST NTC-14A - CHECKING MINIMUM IDLE AIR FLOW

1. Turn ignition off. Remove air cleaner. Disconnect PCV valve hose from vacuum nipple. Install Vacuum Fitting (6714) to intake manifold PCV nipple. Disconnect 3/16" hose from either side of throttle body. Cap 3/16" hose nipple on throttle body. Start engine. Allow engine to reach normal operating temperature.
2. Using DRB, actuate minimum idle airflow. Wait for system to stabilize. If engine speed is not 500-900 RPM, replace throttle body. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If engine speed is 500-900 RPM, minimum airflow is normal. Test is complete.

TEST NTC-15A - NO TROUBLE CODE MECHANICAL TEST

Note. If coming to this test from O2 sensor test and rich or lean condition is not corrected after checking items listed below, replace Powertrain Control Module (PCM).

At this point in diagnostic test procedure, all engine control systems have been determined to be operating as designed and not causing a driveability problem. Following additional items should be checked as possible causes

1. Check if any Tech Service Bulletins (TSBs) apply to vehicle.
2. Check engine vacuum. It must be at least 13 in. Hg in Neutral.
3. Check valve timing.
4. Check engine compression.
5. Check for exhaust system restriction.
6. Ensure PCV system is functioning properly.
7. Check camshaft and crankshaft sprockets.
8. Check torque converter stall speed.
9. Check power booster for internal vacuum leak.
10. Check for fuel contamination.
11. Ensure injector control circuit is connected to correct fuel injector and injector is not plugged or restricted.

TEST NS-1A - QUALIFYING NO-START CONDITION

1. Attempt to crank engine. If engine does not crank, go to «TEST NS-9A»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ns-9a-repairing-no-crank) . If engine cranks, turn ignition off. Disconnect spark plug cable at No. 1 spark plug. Insert an insulated screwdriver in spark plug cable terminal. Hold screwdriver within 1/4" of ground. NOTE: When checking for spark, consider one or two sparks as a no spark condition.
2. While cranking engine for 10 seconds, watch for spark. If a good spark occurs, go to «TEST NS-2A»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ns-2a-inspecting-fuel-system) . If a good spark does not occur, reconnect spark plug cable. Turn ignition off. Disconnect ignition coil secondary cable. Hold coil cable within 1/4" of ground. While cranking engine for 10 seconds, watch for spark.
3. If good spark occurs, repair secondary ignition system as necessary. Perform «TEST VER-1»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-1-no-start-verification) . If a good spark does not occur, turn ignition off. Remove ignition coil secondary cable. Using an external ohmmeter, check resistance of ignition coil secondary cable. If resistance is more than 15 k/ohms, replace ignition coil secondary cable. Perform «TEST VER-1»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-1-no-start-verification) .
4. If resistance is less than 15 k/ohms, remove distributor cap. While watching distributor rotor, crank engine. If rotor does not turn, repair distributor drive system. Perform «TEST VER-1»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-1-no-start-verification) .
5. If rotor turns, reinstall distributor cap. Reinstall the ignition coil secondary cable. Disconnect the ignition coil electrical connector. Inspect all terminals. Repair as required. Perform «TEST VER-1»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-1-no-start-verification) .
6. If terminals are okay, turn ignition on. Using DRB, actuate Auto Shutdown (ASD) relay. Using DRB in voltmeter mode, check voltage on ignition coil connector, ASD relay output circuit Dark Green/Black wire. If voltage is less than 10 volts, repair open in Dark Green/Orange wire or Dark Green/Black wire. Perform «TEST VER-1»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-1-no-start-verification) .
7. If voltage is more than 10 volts, check voltage on ignition coil connector, driver circuit Gray/White wire. If voltage is more than 10 volts, go to next step. If voltage is less than 10 volts, go to step 9).
8. Check valve timing. Adjust valve timing as necessary. Perform «TEST VER-1»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-1-no-start-verification) . If valve timing is okay, replace ignition coil. Perform «TEST VER-1»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-1-no-start-verification) .
9. Turn ignition off. Disconnect Powertrain Control Module (PCM) connector. Using DRB in ohmmeter mode, check resistance of PCM connector terminal No. 19 Gray/White wire. If resistance is less than 5 ohms, repair short to ground in Gray wire or Gray/White wire. Perform «TEST VER-1»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-1-no-start-verification) .
10. If resistance is more than 5 ohms, check resistance of ignition coil driver circuit Gray/White wire between ignition coil connector and PCM connector terminal No. 19 using an external ohmmeter. If resistance is more than 5 ohms, repair open Gray wire or Gray/White wire. Perform «TEST VER-1»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-1-no-start-verification) . If resistance is less than 5 ohms, replace PCM. Perform «TEST VER-1»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-1-no-start-verification) .

TEST NS-2A - INSPECTING FUEL SYSTEM

1. Ensure throttle cables are not holding throttle open. If throttle is held open, repair as required. Perform «TEST VER-1»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-1-no-start-verification) . If throttle is not held open, go to next step.
2. Using DRB, read Throttle Position Sensor (TPS) voltage. If voltage is less than 1.5 volts, go to next step. If voltage is more than 1.5 volts, disconnect TPS connector. Inspect terminals. Repair as required. Perform «TEST VER-1»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-1-no-start-verification) . If terminals are okay, replace TPS. Perform «TEST VER-1»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-1-no-start-verification) .
3. On models not equipped with factory installed theft alarm, go to next step. On models equipped with factory installed theft alarm, read THEFT ALARM status using DRB. If DRB displays FUEL ON, go to next step. If DRB does not display FUEL ON, see appropriate ANTI-THEFT SYSTEM article in ACCESSORIES/SAFETY EQUIP section.
4. Using DRB, actuate fuel system. Listen for fuel pump operation at fuel tank. If fuel pump operation cannot be heard, go to TEST NS-5A. If fuel pump operation can be heard, turn ignition off.
5. Ensure fuel tank is at least 1/4 full. Release fuel pressure. Install a fuel pressure gauge in fuel supply line. Turn ignition on. Using DRB, actuate fuel system. Read fuel pressure gauge reading.
6. If fuel pressure is more than 44 psi (3.3 kg/cm 2 ), go to TEST NS-4B. If fuel pressure is less than 44 psi (3.3 kg/cm 2 ), go to next step.
7. If pressure is less than 34 psi (2.5 kg/cm 2 ), go to TEST NS-4A. If Pressure is more than 34 psi (2.5 kg/cm 2 ), go to next step.
8. If vehicle initially starts and stalls repeatedly, go to TEST NS-7A. If vehicle does not initially start and stall repeatedly, go to TEST NS-3A.

TEST NS-3A - INSPECTING MECHANICAL SYSTEM

Note. For connector terminal identification, see CONNECTOR IDENTIFICATION . For wiring diagram, see WIRING DIAGRAMS article in this section.

1. Disconnect Manifold Absolute Pressure (MAP) sensor connector. Turn ignition on. Using DRB in voltmeter mode, check voltage on MAP sensor connector, 5-volt supply circuit (Violet/White wire). If voltage is less than 4.5 volts, repair open Violet/White wire. Perform «TEST VER-1»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-1-no-start-verification) .
2. If voltage is more than 4.5 volts, reconnect MAP sensor connector. Remove all spark plugs. Inspect spark plug tips for wet fuel. If spark plug tips are wet, clean and reinstall spark plugs. If spark plug tips are not wet, reinstall spark plugs.
3. Inspect spark plug cables for correct placement. Reposition cables as required. Perform «TEST VER-1»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-1-no-start-verification) . If cables are okay, turn ignition off. Check valve timing. Adjust valve timing as necessary. Perform «TEST VER-1»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-1-no-start-verification) . If valve timing is okay, replace MAP sensor. Perform «TEST VER-1»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-1-no-start-verification) .

TEST NS-4A - CORRECTING FUEL DELIVERY

On ZJ body, go to test NS-4C.

TEST NS-4B - CORRECTING FUEL DELIVERY

1. On ZJ body, turn ignition off. Ensure fuel tank is at least 1/4 full. Release fuel pressure. Turn ignition off. Disconnect fuel return hose from fuel rail. Connect a 6-foot fuel hose to fuel fitting. Put other end of 6-foot hose into an approved 2-gallon gasoline container.
2. Turn ignition on. Using DRB, actuate fuel system. If pressure is less than 44 psi (3.3 kg/cm 2 ), go to next step. If pressure is more than 44 psi (3.3 kg/cm 2 ), replace fuel pressure regulator. Perform «TEST VER-1»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-1-no-start-verification) .
3. Stop fuel system actuation. Turn ignition off. Reconnect fuel return hose. Remove fuel return hose from fuel tank. Connect Fuel Pressure Test Adapter (C-6541) to disconnected return hose. Put other end of adapter hose into an approved 2-gallon gasoline container.
4. Turn ignition on. Using DRB, actuate fuel system. Read fuel pressure gauge. Using DRB, stop actuation test. If pressure is less than 44 psi (3.3 kg/cm 2 ), repair restricted fuel pump. Perform «TEST VER-1»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-1-no-start-verification) . If pressure is more than 44 psi (3.3 kg/cm 2 ), repair restricted fuel return line between fuel rail and fuel tank. Perform «TEST VER-1»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-1-no-start-verification) .

TEST NS-4C - CORRECTING FUEL DELIVERY

1. Record fuel pressure gauge reading. Turn ignition off. Release fuel pressure. Remove fuel pressure gauge. Install fuel pressure gauge between fuel tank and fuel filter. Turn ignition on.
2. Using DRB, actuate Auto Shutdown (ASD) fuel system. Record fuel pressure gauge reading. Compare fuel pressure gauge reading with previous reading. If fuel pressure gauge reading is not at least 10 psi more than previous reading, go to step 4). If fuel pressure gauge reading is at least 10 psi more than previous reading, turn ignition off.
3. Inspect fuel lines between fuel filter and fuel rail for restrictions. Repair as required. Perform «TEST VER-1»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-1-no-start-verification) . If no restrictions are observed, replace fuel filter. Perform «TEST VER-1»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-1-no-start-verification) .
4. Turn ignition off. Release fuel pressure. Disconnect fuel return hose at fuel rail. Connect a 6-foot fuel hose to fuel fitting. Put other end of 6-foot hose into an approved 2-gallon gasoline container. Turn ignition on. Using DRB, actuate fuel system. CAUTION: DO NOT allow fuel pressure to exceed 70 psi (4.9 kg/cm 2 ) when squeezing fuel return hose.
5. Gently squeeze 6-foot fuel hose. Read fuel pressure gauge. Using DRB, stop fuel system actuation test. If pressure is more than 34 psi (2.5 kg/cm 2 ), replace fuel pressure regulator. Perform «TEST VER-1»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-1-no-start-verification) . If pressure is less than 34 psi (2.5 kg/cm 2 ), replace fuel pump module. Perform «TEST VER-1»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-1-no-start-verification) .

TEST NS-5A - INSPECTING FUEL PUMP

Note. For connector terminal identification, see CONNECTOR IDENTIFICATION . For wiring diagram, see WIRING DIAGRAMS article in this section.

1. Using DRB, stop actuation test. Using DRB, actuate Auto Shutdown (ASD) relay. Touch fuel pump relay. If fuel pump relay does not pulsate when actuated, go to TEST NS-5B. If fuel pump relay pulsates when actuated, turn ignition off.
2. Remove fuel pump relay. Using DRB in voltmeter mode, check voltage on fuel pump relay connector, battery voltage circuit (Red wire. If voltage is less than 10 volts, repair open Red wire or Red/White wire. Perform «TEST VER-1»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-1-no-start-verification) . If voltage is more than 10 volts, install a known-good relay. Attempt to start engine. If engine starts, replace original relay. Perform «TEST VER-1»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-1-no-start-verification) .
3. If engine does not start, reinstall original fuel pump relay. Disconnect fuel pump harness connector. Ensure fuel pump connector has clean and tight connections. Turn ignition on. Using DRB, actuate fuel system. While still actuating, check voltage on fuel pump connector, output circuit Orange/Black wire using DRB in voltmeter mode. If voltage is less than 10 volts, repair open Dark Green/Black wire or Orange/Black wire. Perform «TEST VER-1»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-1-no-start-verification) . If voltage is more than 10 volts, stop actuation test.
4. Turn ignition off. Using DRB in ohmmeter mode, check resistance of fuel pump connector, ground circuit (Black wire). If resistance is more than 5 ohms, repair open Black wire. Perform «TEST VER-1»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-1-no-start-verification) . If less than 5 ohms, replace fuel pump. Perform «TEST VER-1»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-1-no-start-verification) .

TEST NS-5B - INSPECTING FUEL PUMP

Note. For connector terminal identification, see CONNECTOR IDENTIFICATION . For wiring diagram, see WIRING DIAGRAMS article in this section.

1. Stop actuation test. Turn ignition off. Remove fuel pump relay. Turn ignition on. Using DRB in voltmeter mode, check voltage on fuel pump relay connector, ignition 12-volt supply circuit Light Blue/Red wire.
2. If voltage is less than 10 volts, repair open Dark Blue wire, Light Green/Black wire or Light Blue/Red wire. Perform «TEST VER-1»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-1-no-start-verification). If voltage is more than 10 volts, check resistance across fuel pump relay terminals using an external ohmmeter. (Scheme 39) If resistance is more than 100 ohms, replace fuel pump relay. Perform «TEST VER-1»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-1-no-start-verification). If resistance is less than 100 ohms, repair open Pink wire. Perform «TEST VER-1»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-1-no-start-verification).

Testing Fuel Pump Relay (NS-5B). Scheme 39

TEST NS-6A - CORRECTING NO RESPONSE CONDITION

Note. For connector terminal identification, see CONNECTOR IDENTIFICATION . For wiring diagram, see WIRING DIAGRAMS article in this section.

1. If vehicle starts, go to TEST NS-6B. If vehicle does not start, turn ignition off. Disconnect Throttle Position Sensor (TPS) connector. Turn ignition on.
2. Using DRB in voltmeter mode, check voltage on TPS connector, 5-volt supply circuit (Violet/White wire). If voltage is more than 6 volts, repair open ground circuits at Powertrain Control Module (PCM) connector terminals No. 11 (Black/Tan wire) and No. 12 (Black/Tan wire). Perform «TEST VER-1»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-1-no-start-verification) . If voltage is less than 6 volts, go to next step.
3. If voltage is less than 4.4 volts, go to step 5). If voltage is more than 4.4 volts, reconnect TPS connector. Disconnect Manifold Absolute Pressure (MAP) sensor connector.
4. Using DRB, check voltage on MAP sensor connector, 5-volt supply circuit (Violet/White wire). If voltage is more than 4.4 volts, go to TEST NS-6B. If less than 4.4 volts, replace TPS. Perform «TEST VER-1»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-1-no-start-verification) .
5. Disconnect Manifold Absolute Pressure (MAP) sensor electrical connector. Using DRB, check voltage on TPS connector, 5-volt supply circuit (Violet/White wire). If voltage is more than 4.4 volts, replace MAP sensor. Perform «TEST VER-1»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-1-no-start-verification) .
6. If voltage is less than 4.4 volts, turn ignition off. Disconnect PCM connector. Using DRB in ohmmeter mode, check resistance of PCM connector terminal No. 6, 5-volt supply circuit (Violet/White wire). If resistance is less than 5 ohms, repair short to ground in Violet/White wire. Perform «TEST VER-1»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-1-no-start-verification) .
7. If resistance is more than 5 ohms, check resistance between throttle position sensor connector, ground circuit (Black/Light Blue wire) and PCM connector terminal No. 6 (Violet/White wire) using an external ohmmeter. If resistance is less than 5 ohms, repair short to ground in Violet/White wire. Perform «TEST VER-1»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-1-no-start-verification) .
8. If resistance is more than 5 ohms, turn ignition on. Using DRB in voltmeter mode, check voltage on PCM connector terminal No. 9, ignition 12-volt feed circuit Light Blue wire. If voltage is less than 10 volts, repair open Dark Blue wire, Light Green/Black wire or Light Blue wire between PCM connector and ignition switch. Perform «TEST VER-1»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-1-no-start-verification) .
9. If voltage is more than 10 volts, check voltage on PCM connector terminal No. 3, battery voltage circuit Red wire using DRB. If voltage is more than 10 volts, replace PCM. Perform «TEST VER-1»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-1-no-start-verification) . If voltage is less than 10 volts, go to next step.
10. On ZJ body, remove PCM fuse from Power Distribution Center (PDC). Inspect fuse. If fuse is okay, go to next step. If fuse is blown, go to step 12).
11. Using DRB in voltmeter mode, check voltage on battery voltage side of PDC fuse socket. If voltage is more than 10 volts, repair open Red wire or Red/White wire between PDC fuse socket and PCM connector terminal No. 3. Perform «TEST VER-1»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-1-no-start-verification) . If voltage is less than 10 volts, repair open battery voltage side of PDC fuse socket. Perform «TEST VER-1»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-1-no-start-verification) .
12. Turn ignition off. Remove Auto Shutdown (ASD) relay and fuel pump relay. Using DRB in ohmmeter mode, check resistance of PCM connector terminal No. 3, fused battery voltage circuit Red wire. If resistance is less than 5 ohms, repair short to ground in Red/White wire or Red wire. Replace fuse. Perform «TEST VER-1»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-1-no-start-verification) .
13. If resistance is more than 5 ohms, check resistance of ASD relay connector terminal, output circuit Dark Green/Black wire. If resistance is less than 5 ohms, go to next step. If resistance is more than 5 ohms, go to «TEST NS-6D»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ns-6d-correcting-no-response) .
14. On ZJ body, go to next step.
15. Disconnect ignition coil connector. Using DRB, check resistance of ASD relay connector, output circuit Dark Green/Black wire. If resistance is more than 5 ohms, replace ignition coil. Replace fuse. Perform «TEST VER-1»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-1-no-start-verification) .
16. If resistance is less than 5 ohms, disconnect generator field connector. Using DRB, check resistance of ASD relay connector, output circuit Dark Green/Black wire. If resistance is more than 5 ohms, repair short to ground in generator. Replace fuse. Perform «TEST VER-1»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-1-no-start-verification) . If resistance is less than 5 ohms, go to next step.
17. Disconnect No. 1 fuel injector harness connector. Using DRB, check resistance of ASD relay connector, output circuit Dark Green/Black wire. If resistance is more than 5 ohms, replace No. 1 fuel injector. Replace fuse. Perform «TEST VER-1»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-1-no-start-verification) . If resistance is less than 5 ohms, go to next step.
18. Disconnect No. 2 fuel injector harness connector. Using DRB, check resistance of ASD relay connector, output circuit Dark Green/Black wire. If resistance is more than 5 ohms, replace No. 2 fuel injector. Replace fuse. Perform «TEST VER-1»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-1-no-start-verification) . If resistance is less than 5 ohms, go to next step.
19. Disconnect No. 3 fuel injector harness connector. Using DRB, check resistance of ASD relay connector, output circuit Dark Green/Black wire. If resistance is more than 5 ohms, replace No. 3 fuel injector. Replace fuse. Perform «TEST VER-1»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-1-no-start-verification) . If resistance is less than 5 ohms, go to next step.
20. Disconnect No. 4 fuel injector harness connector. Using DRB, check resistance of ASD relay connector, output circuit Dark Green/Black wire. If resistance is more than 5 ohms, replace No. 4 fuel injector. Replace fuse. Perform «TEST VER-1»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-1-no-start-verification) . If resistance is less than 5 ohms, go to next step.
21. Disconnect No. 5 fuel injector harness connector. Using DRB, check resistance of ASD relay connector, output circuit Dark Green/Black wire. If resistance is more than 5 ohms, replace No. 5 fuel injector. Replace fuse. Perform «TEST VER-1»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-1-no-start-verification) . If resistance is less than 5 ohms, go to next step.
22. Disconnect No. 6 fuel injector harness connector. Using DRB, check resistance of ASD relay connector, output circuit Dark Green/Black wire. If resistance is more than 5 ohms, replace No. 6 fuel injector. Replace fuse. Perform «TEST VER-1»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-1-no-start-verification) . If resistance is less than 5 ohms, go to next step.
23. On 8-cylinder models, go to next step. On 6-cylinder models, repair short to ground in ASD relay connector, output circuit (Dark Green/Orange wire). Perform «TEST VER-1»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-1-no-start-verification) .
24. Disconnect No. 7 fuel injector harness connector. Using DRB, check resistance of ASD relay connector, output circuit Dark Green/Black wire. If resistance is more than 5 ohms, replace No. 7 fuel injector. Replace fuse. Perform «TEST VER-1»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-1-no-start-verification) . If resistance is less than 5 ohms, go to next step.
25. Disconnect No. 8 fuel injector harness connector. Using DRB, check resistance of ASD relay connector, output circuit Dark Green/Black wire. If resistance is more than 5 ohms, replace No. 8 fuel injector. Replace fuse. Perform «TEST VER-1»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-1-no-start-verification) . If resistance is less than 5 ohms, repair short to ground in Dark Green/Orange wire or Dark Green/Black wire. Replace fuse. Perform «TEST VER-1»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-1-no-start-verification) .

TEST NS-6B - CORRECTING NO RESPONSE CONDITION

Note. For connector terminal identification, see CONNECTOR IDENTIFICATION . For wiring diagram, see WIRING DIAGRAMS article in this section.

1. If ignition is not on when NO RESPONSE message is displayed, turn ignition on to get a response. If NO RESPONSE message returns, turn ignition off. Go to next step. If NO RESPONSE message does not return, test is complete. If ignition is on when NO RESPONSE message is displayed, turn ignition off. Go to next step.
2. Disconnect DRB from Data Link Connector (DLC). Disconnect Powertrain Control Module (PCM) connector. Using an external ohmmeter, check resistance between DLC, SCI transmit circuit Black wire and ground. If resistance is less than 5 ohms, repair short to ground in Pink or Black wire. Perform «TEST VER-1»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-1-no-start-verification) .
3. If resistance is more than 5 ohms, use an external ohmmeter to check resistance between DLC, SCI receive circuit Black/Yellow wire and ground. If resistance is less than 5 ohms, repair short to ground in Light Green or Black/Yellow wire. Perform «TEST VER-1»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-1-no-start-verification) .
4. If resistance is more than 5 ohms, check resistance of SCI transmit circuit Black wire between DLC and PCM connector terminal No. 25 using an external ohmmeter. If resistance is more than 5 ohms, repair open Pink or Black wire. Perform «TEST VER-1»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-1-no-start-verification) .
5. If resistance is less than 5 ohms, use an external ohmmeter to check resistance of SCI receive circuit Black/Yellow wire between DLC and PCM connector terminal No. 45. If resistance is more than 5 ohms, repair open Light Green or Black/Yellow wire. Perform «TEST VER-1»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-1-no-start-verification) .
6. If resistance is less than 5 ohms, connect DRB to a functional DLC on another vehicle. Turn ignition on. Using DRB, attempt to read trouble codes. If DRB does not display NO RESPONSE, replace PCM on initial vehicle. Perform «TEST VER-1»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-1-no-start-verification) .
7. If DRB displays NO RESPONSE, substitute another DRB cartridge. Using DRB, attempt to read trouble codes. If DRB does not display NO RESPONSE, replace DRB cartridge. If DRB displays NO RESPONSE, substitute another DRB adapter cable. Using DRB, attempt to read trouble codes. If DRB does not display NO RESPONSE, replace DRB adapter cable. If DRB displays NO RESPONSE, repair or replace DRB.

TEST NS-6C - CORRECTING NO RESPONSE CONDITION

Note. For connector terminal identification, see CONNECTOR IDENTIFICATION . For wiring diagram, see WIRING DIAGRAMS article in this section.

1. Inspect fusible links located in engine compartment near left strut tower. If a fusible link is blown, go to next step. If fusible links are okay, repair open Red wire between Powertrain Control Module (PCM) connector terminal No. 3 and battery positive. Perform «TEST VER-1»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-1-no-start-verification) .
2. Turn ignition off. Remove Auto Shutdown (ASD) and fuel pump relays. Using DRB in ohmmeter mode, check resistance of Powertrain Control Module (PCM) connector terminal No. 3, fused battery voltage circuit (Red wire). If resistance is less than 5 ohms, repair short to ground in Red wire. Perform «TEST VER-1»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-1-no-start-verification) .
3. If resistance is more than 5 ohms, check resistance of ASD relay connector, output circuit (Dark Green/Orange wire). If resistance is less than 5 ohms, go to step 5). If more than 5 ohms, disconnect fuel pump harness connector.
4. Using DRB, check resistance of fuel pump harness connector, output circuit (Dark Green/Black wire). If resistance is less than 5 ohms, repair short to ground in Dark Green/Black wire. Perform «TEST VER-1»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-1-no-start-verification) . If resistance is more than 5 ohms, replace fuel pump. Perform «TEST VER-1»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-1-no-start-verification) .
5. Disconnect Oxygen (O2) sensor(s). Using DRB, check resistance of O2 sensor component side connector(s), relay output circuit (White wire). If resistance is more than 5 ohms, replace O2 sensor(s). Perform «TEST VER-1»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-1-no-start-verification) . If resistance is less than 5 ohms, disconnect ignition coil connector.
6. Using DRB, check resistance of ASD relay connector, output circuit (Dark Green/Orange wire). If resistance is more than 5 ohms, replace ignition coil. Perform «TEST VER-1»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-1-no-start-verification) . If resistance is less than 5 ohms, disconnect generator field connector.
7. Using DRB, check resistance of ASD relay connector, output circuit (Dark Green/Orange wire). If resistance is more than 5 ohms, repair short to ground in generator. Perform «TEST VER-1»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-1-no-start-verification) . If resistance is less than 5 ohms, go to next step.
8. Disconnect No. 1 fuel injector harness connector. Using DRB, check resistance of ASD relay connector, output circuit (Dark Green/Orange wire). If resistance is more than 5 ohms, replace No. 1 fuel injector. Replace fuse. Perform «TEST VER-1»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-1-no-start-verification) . If resistance is less than 5 ohms, go to next step.
9. Disconnect No. 2 fuel injector harness connector. Using DRB, check resistance of ASD relay connector, output circuit (Dark Green/Orange wire). If resistance is more than 5 ohms, replace No. 2 fuel injector. Replace fuse. Perform «TEST VER-1»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-1-no-start-verification) . If resistance is less than 5 ohms, go to next step.
10. Disconnect No. 3 fuel injector harness connector. Using DRB, check resistance of ASD relay connector, output circuit (Dark Green/Orange wire). If resistance is more than 5 ohms, replace No. 3 fuel injector. Replace fuse. Perform «TEST VER-1»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-1-no-start-verification) . If resistance is less than 5 ohms, go to next step.
11. Disconnect No. 4 fuel injector harness connector. Using DRB, check resistance of ASD relay connector, output circuit (Dark Green/Orange wire). If resistance is more than 5 ohms, replace No. 4 fuel injector. Replace fuse. Perform «TEST VER-1»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-1-no-start-verification) . If resistance is less than 5 ohms, go to next step.
12. Disconnect No. 5 fuel injector harness connector. Using DRB, check resistance of ASD relay connector, output circuit (Dark Green/Orange wire). If resistance is more than 5 ohms, replace No. 5 fuel injector. Replace fuse. Perform «TEST VER-1»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-1-no-start-verification) . If resistance is less than 5 ohms, go to next step.
13. Disconnect No. 6 fuel injector harness connector. Using DRB, check resistance of ASD relay connector, output circuit (Dark Green/Orange wire). If resistance is more than 5 ohms, replace No. 6 fuel injector. Replace fuse. Perform «TEST VER-1»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-1-no-start-verification) . If resistance is less than 5 ohms, go to next step.
14. On 8-cylinder models, go to next step. On 6-cylinder models, repair short to ground in ASD relay connector, output circuit (Dark Green/Orange wire). Replace fuse. Perform «TEST VER-1»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-1-no-start-verification) .
15. Disconnect No. 7 fuel injector harness connector. Using DRB, check resistance of ASD relay connector, output circuit (Dark Green/Orange wire). If resistance is more than 5 ohms, replace No. 7 fuel injector. Replace fuse. Perform «TEST VER-1»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-1-no-start-verification) . If resistance is less than 5 ohms, go to next step.
16. Disconnect No. 8 fuel injector harness connector. Using DRB, check resistance of ASD relay connector, output circuit (Dark Green/Orange wire). If resistance is more than 5 ohms, replace No. 8 fuel injector. Replace fuse. Perform «TEST VER-1»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-1-no-start-verification) . If resistance is less than 5 ohms, repair short to ground in Dark Green/Orange wire. Replace fuse. Perform «TEST VER-1»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-1-no-start-verification) .

TEST NS-6D - CORRECTING NO RESPONSE CONDITION

Note. For connector terminal identification, see CONNECTOR IDENTIFICATION . For wiring diagram, see WIRING DIAGRAMS article in this section.

1. On ZJ body, disconnect fuel pump harness connector and Oxygen (O2) sensor connector. Using DRB in ohmmeter mode, check resistance of fuel pump relay, output circuit (Orange/Dark Blue wire) at Power Distribution Center (PDC). If resistance is less than 5 ohms, repair short to ground in Orange/Dark Blue wire. Perform «TEST VER-1»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-1-no-start-verification) .
2. If resistance is more than 5 ohms, using DRB, check resistance of O2 sensor connector, relay output circuit (White wire). If resistance is less than 5 ohms, replace O2 sensor. Replace fuse. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If resistance is more than 5 ohms, replace fuel pump. Replace fuse. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .
3. Disconnect fuel pump harness connector. Using DRB in ohmmeter mode, check resistance of fuel pump relay connector, output circuit (Dark Green/Black wire). If resistance is less than 5 ohms, repair short to ground in Dark Green/Black wire. Replace fuse. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) . If resistance is more than 5 ohms, replace fuel pump. Replace fuse. Perform «TEST VER-2»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-2-road-test-verification) .

TEST NS-7A - INSPECTING IDLE AIR CONTROL MOTOR OPERATION

Note. For connector terminal identification, see CONNECTOR IDENTIFICATION . For wiring diagram, see WIRING DIAGRAMS article in this section.

1. Disconnect Idle Air Control (IAC) motor connector. Turn ignition on. Using DRB, actuate IAC motor. Using DRB in voltmeter mode, check voltage on IAC motor connector, driver No. 3 circuit Yellow/Black wire. If voltage is less than one volt, go to «TEST NS-7B»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ns-7b-inspecting-idle-air) .
2. If voltage is more than one volt, check voltage on IAC motor connector, driver No. 1 circuit (Brown/White wire). If voltage is less than one volt, go to «TEST NS-7C»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ns-7c-inspecting-idle-air) .
3. If voltage is more than one volt, check voltage on IAC motor connector, driver No. 4 circuit Gray/Red wire. If voltage is less than one volt, go to «TEST NS-7D»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ns-7d-inspecting-idle-air) .
4. If voltage is more than one volt, check voltage on IAC motor connector, driver No. 2 circuit Violet/Black wire. If voltage is less than one volt, go to «TEST NS-7E»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ns-7e-inspecting-idle-air) .
5. If voltage is more than one volt, turn ignition off. Remove IAC motor from throttle body. Reconnect IAC motor connector. Turn ignition on. Using DRB, actuate IAC motor. If IAC motor pintle moves in and out, go to «TEST NS-8A»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ns-8a-correcting-start) . If IAC motor pintle does not move in and out, replace IAC motor. Perform «TEST VER-1»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-1-no-start-verification) .

TEST NS-7B - INSPECTING IDLE AIR CONTROL MOTOR OPERATION

Note. For connector terminal identification, see CONNECTOR IDENTIFICATION . For wiring diagram, see WIRING DIAGRAMS article in this section.

1. Turn ignition off. Disconnect Powertrain Control Module (PCM) connector. Inspect connectors for damaged, pushed-out or miswired terminals. Repair as required. Perform «TEST VER-1»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-1-no-start-verification) . If PCM terminals are okay, go to next step.
2. Using an external ohmmeter, check resistance of driver No. 3 circuit Yellow/Black wire between IAC motor connector and PCM connector terminal No. 39. If resistance is less than 5 ohms, replace PCM. Perform «TEST VER-1»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-1-no-start-verification) . If resistance is more than 5 ohms, repair open Gray/Red wire or Yellow/Black wire. Perform «TEST VER-1»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-1-no-start-verification) .

TEST NS-7C - INSPECTING IDLE AIR CONTROL MOTOR OPERATION

Note. For connector terminal identification, see CONNECTOR IDENTIFICATION . For wiring diagram, see WIRING DIAGRAMS article in this section.

1. Turn ignition off. Disconnect Powertrain Control Module (PCM) connector. Inspect connectors for damaged, pushed-out or miswired terminals. Repair as required. Perform «TEST VER-1»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-1-no-start-verification) . If PCM terminals are okay, go to next step.
2. Using an external ohmmeter, check resistance of driver No. 1 circuit (Brown/White wire) between IAC motor connector and PCM connector terminal No. 40. If resistance is less than 5 ohms, replace PCM. Perform «TEST VER-1»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-1-no-start-verification) . If resistance is more than 5 ohms, repair open Brown/White wire. Perform «TEST VER-1»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-1-no-start-verification) .

TEST NS-7D - INSPECTING IDLE AIR CONTROL MOTOR OPERATION

Note. For connector terminal identification, see CONNECTOR IDENTIFICATION . For wiring diagram, see WIRING DIAGRAMS article in this section.

1. Turn ignition off. Disconnect Powertrain Control Module (PCM) connector. Inspect connectors for damaged, pushed-out or miswired terminals. Repair as required. Perform «TEST VER-1»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-1-no-start-verification) . If PCM terminals are okay, go to next step.
2. Using an external ohmmeter, check resistance of driver No. 4 circuit Gray/Red wire between IAC motor connector and PCM connector terminal No. 59. If resistance is less than 5 ohms, replace PCM. Perform «TEST VER-1»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-1-no-start-verification) . If resistance is more than 5 ohms, repair open Violet/Black wire. Perform «TEST VER-1»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-1-no-start-verification) .

TEST NS-7E - INSPECTING IDLE AIR CONTROL MOTOR OPERATION

Note. For connector terminal identification, see CONNECTOR IDENTIFICATION . For wiring diagram, see WIRING DIAGRAMS article in this section.

1. Turn ignition off. Disconnect Powertrain Control Module (PCM) connector. Inspect connectors for damaged, pushed-out or miswired terminals. Repair as required. Perform «TEST VER-1»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-1-no-start-verification) . If PCM terminals are okay, go to next step.
2. Using external ohmmeter, check resistance of driver No. 2 circuit Violet/Black wire between IAC motor connector and PCM connector terminal No. 60. If resistance is more than 5 ohms, repair open Yellow/Black wire or Violet/Black wire. Perform «TEST VER-1»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-1-no-start-verification) . If resistance is less than 5 ohms, replace PCM. Perform «TEST VER-1»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-1-no-start-verification) .

TEST NS-8A - CORRECTING START & STALL CONDITION

At this point in diagnostic test procedure, all engine control systems have been determined to be operating as designed and not causing a start and stall problem. Check following items as possible causes

1. Check if any Tech Service Bulletins (TSBs) apply to vehicle.
2. Check valve timing.
3. Check engine compression.
4. Check for exhaust system restriction.
5. Ensure PCV system is functioning properly.
6. Check camshaft and crankshaft sprockets.
7. Check for fuel contamination.
8. Check secondary ignition system.

TEST NS-9A - REPAIRING NO CRANK CONDITION

Note. For connector terminal identification, see CONNECTOR IDENTIFICATION . For wiring diagram, see WIRING DIAGRAMS article in this section.

1. If vehicle is equipped with manual transmission, go to «TEST NS-9B»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ns-9b-repairing-no-crank) . If vehicle is equipped with automatic transmission, ensure transmission is in PARK position.
2. Using DRB, read park/neutral position switch sense. If park/neutral position switch senses PARK, go to next step. If park/neutral position switch does not sense PARK, repair open in park/neutral position switch ground circuit.
3. Disconnect starter relay. Using DRB in voltmeter mode, check voltage on starter relay connector, battery supply circuit Red/White wire. If voltage is less than 10 volts, repair open in Black wire or Red/White wire. Perform «TEST VER-1»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-1-no-start-verification) .
4. If voltage is more than 10 volts, check voltage on ignition switch connector, output circuit Yellow/Dark Blue wire using an external voltmeter. Hold ignition switch in RUN position while observing voltmeter. If voltage is less than 10 volts, repair open Yellow wire or Yellow/Dark Blue wire. Perform «TEST VER-1»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-1-no-start-verification) . If voltage is more than 10 volts, go to next step. WARNING: Engine may crank in following step, keep away from moving engine parts.
5. Ensure transmission is in PARK position and parking brake is set. Briefly connect a jumper wire between starter relay connector, battery supply circuit Red/White wire and ignition switch connector, output circuit Yellow/Dark Blue wire. Go to TEST NS-9C.

TEST NS-9B - REPAIRING NO CRANK CONDITION

Note. For connector terminal identification, see CONNECTOR IDENTIFICATION . For wiring diagram, see WIRING DIAGRAMS article in this section.

1. Disconnect starter relay. Using DRB in ohmmeter mode, check resistance on starter relay connector, ground circuit Black/White wire. If resistance is more than 5 ohms, repair open Brown/Yellow wire or Black/White wire. Perform «TEST VER-1»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-1-no-start-verification) .
2. If resistance is less than 5 ohms, put DRB in voltmeter mode. Using DRB, check voltage on starter relay connector, battery supply circuit Red/White wire. If voltage is less than 10 volts, repair open Black wire or Red/White wire. Perform «TEST VER-1»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-1-no-start-verification) .
3. If voltage is more than 10 volts, using an external voltmeter, check voltage on ignition switch connector, output circuit Yellow/Dark Blue wire. Hold ignition switch in RUN position while observing voltmeter. If voltage is less than 10 volts, repair open Yellow wire or Yellow/Dark Blue wire. Perform «TEST VER-1»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-1-no-start-verification) . If voltage is more than 10 volts, go to next step. WARNING: Engine may crank in following step, keep away from moving engine parts.
4. Ensure transmission is in NEUTRAL position and parking brake is set. Briefly connect a jumper wire between starter relay connector, battery supply circuit Red/White wire and ignition switch connector, output circuit Yellow/Dark Blue wire. Go to TEST NS-9C.

TEST NS-9C - REPAIRING NO CRANK CONDITION

Note. For connector terminal identification, see CONNECTOR IDENTIFICATION . For wiring diagram, see WIRING DIAGRAMS article in this section.

1. If engine cranked, replace starter relay. Perform «TEST VER-1»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-1-no-start-verification) . If engine did not crank, disconnect jumper wire. Note if starter solenoid clicked when jumper wire was connected. Disconnect starter relay output wire Light Green/Black wire from starter solenoid.
2. Using an external ohmmeter, check resistance of Brown wire or Light Green/Black wire between starter relay connector and starter solenoid. If resistance is more than 5 ohms, repair open in Brown wire or Light Green/Black wire. Perform «TEST VER-1»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-1-no-start-verification) . If resistance is less than 5 ohms, reinstall starter relay.
3. Check battery cables for high resistance. If either battery circuit had a voltage drop of more than .2 volt, repair battery circuit for high resistance. Perform «TEST VER-1»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-1-no-start-verification) . If voltage drop for either battery circuit is less than .2 volt, go to next step.
4. If starter solenoid clicked when jumper wire was connected in step 1), repair starter for a mechanical failure. Perform «TEST VER-1»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-1-no-start-verification) . If starter solenoid did not click when jumper wire was connected in step 1), replace starter solenoid. Perform «TEST VER-1»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-ver-1-no-start-verification) .

TEST VER-1 - NO START VERIFICATION PROCEDURE

1. Inspect vehicle to ensure all engine components are connected. Reassemble and reconnect components as necessary. Inspect engine oil for fuel contamination. Change oil and filter if necessary. Attempt to start engine.
2. If engine does not start, check if any Tech Service Bulletins (TSBs) apply to vehicle and return to «TEST TC-1A»(/jeep/grand-cherokee/zj-1992-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-52l__test-tc-1a-checking-system-for) , if necessary. If engine starts and Powertrain Control Module (PCM) was changed, repair is complete. If engine starts and PCM was not changed, connect DRB to PCM data link connector and erase trouble codes. Repair is complete.

TEST VER-2 - ROAD TEST VERIFICATION PROCEDURE

Inspect vehicle to ensure all engine components are connected. Reassemble and reconnect components as necessary. If another trouble code was read previously and not corrected, return to TEST TC-1A and follow path specified by other trouble code. If Powertrain Control Module (PCM) has not been replaced, perform following

1. Connect DRB to PCM Data Link Connector (DLC), and erase trouble codes.
2. Using DRB, reset all values in adaptive memory.
3. Disconnect DRB.

To ensure no other trouble code remains on models with A/C, perform following

1) Turn on A/C and blower motor. Drive vehicle for at least 5 minutes and attain a speed of at least 40 MPH. Ensure transmission shifts through all gears.

2) Upon completion of road test, turn engine off. Restart engine, and let it idle for at least 2 minutes. Turn engine off. Connect DRB to PCM DLC.

3) Read all trouble codes. If repaired trouble code has reset, repair is not complete. Check all pertinent Tech Service Bulletins (TSBs), and return to TEST TC-1A , if necessary. If another trouble code exists, return to TEST TC-1A and follow path specified by other trouble code. If no other trouble codes exist, repair is now complete.

SUMMARY

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

Wiring Diagram (5.2L - 1 Of 2). Scheme 40

Wiring Diagram (5.2L - 2 Of 2). Scheme 41

See also:
• TESTS W/O CODES
• COMPUTER RELEARN PROCEDURES
• TESTS W/CODES - BODY CONTROL COMPUTER
• TEST NTC-1A
• VISUAL INSPECTION
• ENTERING ON-BOARD DIAGNOSTICS
• TEST NS-1A
• TEST TC-1A
• TROUBLE CODES/MESSAGES
• CLEARING TROUBLE CODES
• CONNECTOR IDENTIFICATION
• TEST NS-6A
• TEST TC-2A
• TEST TC-3A
• TEST TC-4A
• TEST TC-5A
• TEST TC-6A
• TEST TC-7A
• TEST TC-8A
• TEST TC-9A
• TEST TC-10A
• TEST TC-11A
• TEST TC-12A
• TEST TC-13A
• TEST TC-14A
• TEST TC-15A
• TEST TC-16A
• TEST TC-17A
• TEST TC-18A
• TEST TC-19A
• TEST TC-20A
• TEST TC-21A
• TEST TC-22A
• TEST TC-23A
• TEST TC-24A
• TEST TC-24B
• TEST TC-25A
• TEST TC-26A
• TEST TC-27A
• TEST TC-28A
• TEST TC-29A
• TEST TC-30A
• TEST TC-31A
• TEST TC-32A
• TEST TC-33A
• TEST TC-34A
• TEST TC-35A
• TEST TC-36A
• TEST TC-37A
• TEST TC-38A
• TEST TC-39A
• TEST TC-40A
• TEST TC-41A
• TEST TC-42A
• TEST VER-1
• TEST VER-2
• TEST TC-23B
• TEST TC-23C
• TEST TC-23D
• TEST TC-23E
• TEST NTC-2A
• TEST NTC-3A
• TEST NTC-4A
• TEST NTC-5A
• TEST NTC-6A
• TEST NTC-7A
• TEST NTC-8A
• TEST NTC-9A
• TEST NTC-10A
• TEST NTC-11A
• TEST NTC-12A
• TEST NTC-13A
• TEST NTC-14A
• TEST NTC-15A
• FUEL PRESSURE RELEASE
• TEST NTC-8B
• TEST NS-9A
• TEST NS-2A
• TEST NS-6D
• TEST NS-7B
• TEST NS-7C
• TEST NS-7D
• TEST NS-7E
• TEST NS-8A
• TEST NS-9B