Infiniti J30 1994 - 1994 ENGINE PERFORMANCE Self-Diagnostics - J30

Infiniti J30 1994 - INTRODUCTION

If no faults were found while performing BASIC DIAGNOSTIC PROCEDURES, proceed with self-diagnostics. If no fault codes or only pass codes are present after entering self-diagnostics, proceed to TESTS W/O CODES article for diagnosis by symptom (i.e., ROUGH IDLE, NO START, etc.).

Infiniti J30 1994 - SELF-DIAGNOSTIC SYSTEM

Self-diagnostic system is used for diagnosing malfunctions of Electronic Concentrated Control System (ECCS) sensors and actuators. Electronic Control Module (ECM) has 2 available diagnostic modes. Before entering self-diagnostics, perform BASIC DIAGNOSTIC PROCEDURES. This prevents wasted diagnostic time and invalid diagnostic results.

Infiniti J30 1994 - CONSULT TESTER

In addition to self-diagnostic capability, all models are equipped with a Data Link Connector (DLC) for use with CONSULT Tester (J-38465). DLC is located in left dash side panel.

NOTE:

When performing BASIC DIAGNOSTIC PROCEDURES, DO NOT erase any diagnostic information stored in ECM memory.

NOTE:

CHECK ENGINE light is now referred to as Malfunction Indicator Light (MIL).

Infiniti J30 1994 - HARD FAILURES

Hard failures cause Malfunction Indicator Light (MIL) to glow and remain on until problem is repaired. If light comes on and remains on (light may flash) during vehicle operation, cause of malfunction must be determined using diagnostic code charts. If a sensor fails, control unit will use a substitute value in its calculations to continue engine operation. In this condition, commonly known as limp-in mode, vehicle runs but driveability will not be optimum.

Infiniti J30 1994 - INTERMITTENT FAILURES

Intermittent failures may cause Malfunction Indicator Light (MIL) to flicker or glow and go out after intermittent fault goes away. However, corresponding trouble code will be stored in ECM memory. Not all trouble codes will illuminate MIL. If related fault does not reoccur within a certain time frame, related trouble code will be erased from ECM memory. Intermittent failures may be caused by sensor, connector or wiring related problems. See INTERMITTENTS in TESTS W/O CODES article.

NOTE:

Follow proper diagnostic routine when diagnosing system. See DIAGNOSTIC ROUTINE table.

Infiniti J30 1994 DIAGNOSTIC ROUTINE

Procedure	Order
Basic Diagnostic Procedures (1)	1st
Entering Diagnostics	2nd
Retrieving Trouble Codes	3rd
Symptoms (2)	4th
Intermittents (2)	5th
(1) See BASIC DIAGNOSTICS PROCEDURES article. (2) See TESTS W/O CODES article.

Infiniti J30 1994 - MALFUNCTION INDICATOR LIGHT (MIL)

NOTE:

Not all trouble codes activate MIL.

All models are equipped with a Malfunction Indicator Light (MIL). As a bulb check, light glows when ignition is turned on and engine is not running.

On California models, MIL glows when a fault is detected with engine running. A corresponding trouble code will set in ECM memory. MIL also glows if ECM or camshaft/crankshaft position sensor malfunctions.

On Federal models, MIL glows only when ECM or camshaft/crankshaft position sensor malfunctions with engine running.

Infiniti J30 1994 - DIAGNOSTIC MODES

Self-diagnostic system can detect ECCS malfunctions and store related trouble codes. Intermittent codes are also stored. All codes are stored until cleared from memory. If an intermittent fault does not reoccur within 50 ignition key cycles, it will be cleared from memory.

Switching modes is not possible when engine is running. During diagnosis, self-diagnostic system will automatically return to Mode I from Mode II when ignition is turned off.

Infiniti J30 1994 - Mode I

This is normal operating mode. In this mode, Malfunction Indicator Light (MIL) and Red LED inspection light in ECM stay on when ignition is turned on, engine off (bulb check). If engine is started, MIL and Red LED in ECM should turn off, unless a fault or trouble code is present (California) or if ECM or camshaft/crankshaft position sensor is malfunctioning (California and Federal).

Infiniti J30 1994 - Mode II

This is self-diagnostic mode for retrieving fault or trouble codes. See RETRIEVING CODES. With engine running, Mode II can monitor air/fuel mixture feedback control. MIL and Red LED in ECM will flash on (lean) and off (rich) more than 5 times every 10 seconds with engine speed at 2000 RPM when system is in closed loop. MIL and Red LED do not flash (remain on or off) if system is in open loop.

Infiniti J30 1994 - ECM LOCATION

ECM is located behind right kick panel.

Infiniti J30 1994 - ENTERING SELF-DIAGNOSTICS

1. Turn ignition on, but leave engine off. Using a small screwdriver, turn diagnostic mode selector on ECM fully clockwise. Wait at least 2 seconds, and then turn diagnostic mode selector fully counterclockwise. Mode II self-diagnostics will result, and MIL and Red LED inspection light will flash codes (if present).
2. If engine is started at this stage, MIL and Red LED inspection light will display condition of air/fuel mixture, monitored by HO2S sensor, whether system is in closed or open loop.

NOTE:

Turn diagnostic mode selector fully counterclockwise whenever vehicle is in use. Switching modes is not possible when engine is running.

Infiniti J30 1994 - RETRIEVING CODES

Use Mode II to retrieve trouble codes. Read codes using either Malfunction Indicator Light (MIL) or Red LED inspection light on ECM. Trouble codes will flash after selecting Mode II.

Trouble codes are indicated by number of flashes from MIL or Red LED inspection light. For example, 3 long (.6 second) flashes followed by 2 short (.3 second) flashes of MIL or Red LED indicate a Code 32. There will be a .9 second pause between long and short flash groups. There will be a 2.1 second pause between codes.

Infiniti J30 1994 - CLEARING CODES

NOTE:

Ensure all diagnostic codes are accessed from ECM memory before disconnecting battery or switching from Mode II to Mode I.

Infiniti J30 1994 - Memory Erase

Stored memory can be erased by disconnecting battery or selecting Mode I after Mode II has been accessed.

Infiniti J30 1994 - FINAL CHECK FINAL CHECK FOR ALL CODE CHARTS

Unless otherwise instructed in code inspection, perform following FINAL CHECK after each repair is completed.

• Erase Diagnostic Test Mode II (Self-Diagnostic Results) memory. See CLEARING CODES under SELF-DIAGNOSTIC SYSTEM.
• Ensure Code 55 (no malfunction) is displayed in self- diagnostic mode.
• Perform a test drive.
• Perform Diagnostic Test Mode II (Self-Diagnostic Results) again. If results are okay, inspection is complete. If results are not okay, verify ECM pin terminals or harness connector are not damaged.

Infiniti J30 1994 - SUMMARY

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

Infiniti J30 1994 - TROUBLE CODE DEFINITION

NOTE:

When DTC tests indicate to check a component, see indicated component in I - SYS/COMP TESTS article. For Diagnostic Trouble Code (DTC) illustration symbol identification, see Fig. 1 . To identify ECM connector terminals, see WIRING DIAGRAMS article.

Infiniti J30 1994 TROUBLE CODE IDENTIFICATION

Code	System Affected	Probable Cause
11 (1)	Camshaft/Crankshaft Position Sensor	(2) No Crank Signal
12	Mass Airflow Sensor Circuit	Open/Shorted Circuit
13	Engine Coolant Temperature Sensor	Open/Shorted Circuit
14	Vehicle Speed Sensor (VSS)	No VSS Signal
21 (1)	Ignition Signal Circuit	(2) Open/Shorted Circuit
31	ECM	Signals Not Normal
32 (3)	EGR Function	No EGR Operation
33	HO2S Sensor (LEFT)	Open/Shorted Circuit/High HO2S Signal
34 (1)	Knock Sensor	Open/Shorted Circuit
35 (3)	EGR Temperature Sensor	Open/Shorted Circuit
42 (1)	Fuel Temperature Sensor	Open/Shorted Circuit
43	Throttle Position Sensor	Open/Shorted Circuit
45 (3)	Injector Leak.	Leak At Injectors
51 (4)	Injector Circuit	Injector Does Not Work.
53	HO2S Sensor (Right).	Open/Shorted Circuit/High HO2S Signal
54 (1)	Automatic Transmission Signal	Open Signal Transmission Control Unit.
55 (1)	No Malfunction	Normal Condition
(1) Trouble code will not activate Malfunction Indicator Light (MIL). (2) If Codes 11 and 21 are present at same time3, check items causing a malfunction of camshaft/rankshaft position sensor circuit first. (3) California models. (4) Models with automatic transmission, Serial No. 450021 and later.

Fig. 1: Infiniti J30 1994 - Component Locations - Identifying DTC Illustration Symbols

Infiniti J30 1994 - DIAGNOSTIC TROUBLE CODE (DTC) TESTING (J30)

NOTE:

Procedures using CONSULT Tester (J-38465) will be shown when available. If CONSULT Tester is not available, disregard steps using CONSULT Tester and use alternate test procedure.

NOTE:

In the following DTC testing, when instructed to perform "FINAL CHECK", see FINAL CHECK in this article.

Infiniti J30 1994 - ECM HARNESS CONNECTOR

NOTE:

To locate ECM and identify ECM connector terminals, see Fig. 2 and Fig. 3 .

Fig. 2: Infiniti J30 1994 - Component Locations - Locating ECM Harness Connector (J30)

Fig. 3: Infiniti J30 1994 - Component Locations - ECM Harness Connector Terminals (J30)

Infiniti J30 1994 - DTC 11: CRANKSHAFT POSITION (CKP) SENSOR 1) Check Power Supply

Turn ignition off and disconnect CKP sensor harness connector. Turn ignition on. Measure voltage between CKP sensor harness connector terminal "b" (Black/White wire) and ground. See Fig. 4 and Fig. 5 . If battery voltage is present, go to next step. If battery voltage is not present, verify harness continuity between CKP sensor and ECCS relay (Black/White wire), and between CKP sensor and ECM (Black/White wire). Repair harness or connectors as necessary.

Fig. 4: Infiniti J30 1994 - Component Locations - Locating CKP Sensor Harness Connector

Fig. 5: Infiniti J30 1994 - Component Locations - DTC 11, Checking Power Supply

Infiniti J30 1994 - 2) Check Input Signal Circuit

Turn ignition off and disconnect ECM harness connector. Verify harness continuity between CKP sensor connector terminal "d" (Green/Black wire) and ECM connector terminals No. 41 and 51 (120-degree signal), and between terminal "c" (Green/Yellow wire) and ECM terminals No. 42 and 52 (one degree signal). See Fig. 2 , Fig. 3 and Fig. 6 . If continuity is present, go to next step. If continuity is not present, repair harness or connectors as necessary.

Infiniti J30 1994 - 3) Check Component

Inspect CKP sensor. See SYSTEM & COMPONENT TESTING article. Replace CKP sensor if necessary and perform FINAL CHECK.

Fig. 6: Infiniti J30 1994 - Component Locations - DTC 11, Checking Input Signal Circuit

Infiniti J30 1994 - DTC 12: MASS AIRFLOW (MAF) SENSOR 1) Check Power Supply

Turn ignition off and disconnect MAF sensor harness connector. Turn ignition on. Measure voltage between MAF sensor harness connector terminal "b" (Black/White wire) and ground. See Fig. 7 and Fig. 8 . If battery voltage is present, go to next step. If battery voltage is not present, verify harness continuity between MAF sensor and ECM, and MAF sensor and ECCS relay. Repair harness or connectors as necessary.

Fig. 7: Infiniti J30 1994 - Component Locations - Locating MAF Sensor Harness Connector

Fig. 8: Infiniti J30 1994 - Component Locations - DTC 12, Checking Power Supply

Infiniti J30 1994 - 2) Check Input Signal Circuit

Turn ignition off and disconnect ECM harness connector. Check continuity between MAF sensor connector terminal "e" (White wire) and ECM terminal No. 27. If continuity is present, go to next step. If continuity is not present, repair harness or connectors as necessary. See Fig. 2 , Fig. 3 and Fig. 9 .

Infiniti J30 1994 - 3) Check Component

Inspect MAF sensor. See SYSTEM & COMPONENT TESTING article. Replace MAF sensor if necessary and perform FINAL CHECK.

Fig. 9: Infiniti J30 1994 - Component Locations - DTC 12, Checking Input Signal Circuit

Infiniti J30 1994 - DTC 13: ENGINE COOLANT TEMPERATURE (ECT) SENSOR 1) Check Power Supply

Turn ignition off and disconnect ECT sensor harness connector. Turn ignition on. Measure voltage between ECT sensor harness connector terminal "b" (Yellow/Green wire) and ground. See Fig. 10 and Fig. 11 . If voltage is approximately 5 volts, go to next step. If voltage is not as specified, verify harness continuity between ECT sensor and ECM. Repair harness or connectors as necessary.

Fig. 10: Infiniti J30 1994 - Component Locations - Locating ECT Sensor Harness Connector

Fig. 11: Infiniti J30 1994 - Component Locations - DTC 13, Checking Power Supply

Infiniti J30 1994 - 2) Check Ground Circuit

Turn ignition off. Check ECT sensor harness continuity between terminal "a" (Orange/Blue wire) and engine ground. See Fig. 12 . If continuity is present, go to next step. If continuity is not present, verify harness continuity between ECT sensor terminal "a" and ECM terminal No. 30 (Orange/Blue wire), and between automatic transmission control unit terminal No. 35 (48-pin connector located on driver side kick panel) and ECT sensor terminal "a" (Orange/Blue wire). Repair harness or connectors as necessary.

Infiniti J30 1994 - 3) Check Component

Inspect ECT sensor. See I - SYS/COMP TESTS article. Replace ECT sensor if necessary and perform FINAL CHECK.

Fig. 12: Infiniti J30 1994 - Component Locations - DTC 13, Checking Ground Circuit

Infiniti J30 1994 - DTC 14: VEHICLE SPEED SENSOR (VSS) 1) Check Speedometer Operation

Ensure speedometer operates properly. If speedometer operates properly, go to next step. VSS is located on transmission rear extension. If speedometer does not operate properly, remove VSS from transmission. Turn speedometer pinion quickly. Measure voltage between terminals "a" and "b" at VSS connector. If voltage is approximately .5 volt and alternating, go to next step. If voltage is not as specified, replace VSS.

Infiniti J30 1994 - 2) Check Input Signal Circuit

Turn ignition off and disconnect ECM harness connector and combination meter harness connector. Check harness continuity between ECM terminal No. 53 and combination meter terminal "a" (Black/Yellow wire). See Fig. 2 , Fig. 3 , Fig. 13 and Fig. 14 . If continuity is not present, repair harness or connectors as necessary and perform FINAL CHECK.

Fig. 13: Infiniti J30 1994 - Component Locations - Locating Combination Meter Harness Connector

Fig. 14: Infiniti J30 1994 - Component Locations - DTC 14, Checking Input Signal Circuit

Infiniti J30 1994 - DTC 21: IGNITION SIGNAL 1) Start engine.

If engine does not start, go to next step. If engine starts, go to step 3) or to step 4).

Infiniti J30 1994 - 2) Check Ground Circuit

If engine does not start, turn ignition off. Disconnect Power Transistor Unit (PTU) harness connector. Verify harness continuity between PTU harness connector terminal "d" (Black wire) and engine ground. See Fig. 15 -19. If continuity is present, go to step 4). If continuity is not present, repair harness or connectors as necessary and perform FINAL CHECK.

Fig. 15: Infiniti J30 1994 - Component Locations - Locating Ignition Coil Relay

Fig. 16: Infiniti J30 1994 - Component Locations - Locating Ignition Coil Harness Connector

Fig. 17: Infiniti J30 1994 - Component Locations - Locating Power Transistor Unit Harness Connector

Fig. 18: Infiniti J30 1994 - Component Locations - Locating EFI Harness Connectors

Fig. 19: Infiniti J30 1994 - Component Locations - DTC 21, Checking Ground Circuit

Infiniti J30 1994 - 3) Search For Malfunctioning Circuit Using CONSULT

Turn ignition off and connect CONSULT. Perform POWER BALANCE in ACTIVE TEST mode with CONSULT. Search for circuit which does not produce a momentary engine speed drop.

Infiniti J30 1994 - 4) Check Output Signal Circuit

Turn ignition off. Disconnect ECM harness connector and PTU harness connector. Verify harness continuity between ECM harness connector terminals and PTU harness connector terminals as follows:

• ECM terminal No. 1 and PTU terminal "g" (Yellow wire).
• ECM terminal No. 2 and PTU terminal "f" (Light Green/Black wire).
• ECM terminal No. 3 and PTU terminal "e" (White wire).
• ECM terminal No. 11 and PTU terminal "c" (Pink/Black wire).
• ECM terminal No. 12 and PTU terminal "b" (Red/Blue wire).
• ECM terminal No. 13 and PTU terminal "a" (Gray wire).

See Fig. 20 . If continuity is present, go to next step. If continuity is not present, verify harness continuity between ECM connector and PTU connector. Repair harness or connectors as necessary.

Infiniti J30 1994 - 5) Check Component

Inspect power transistor unit. See SYSTEM & COMPONENT TESTING article. Replace power transistor unit if necessary and perform FINAL CHECK.

Fig. 20: Infiniti J30 1994 - Component Locations - DTC 21, Checking Output Signal Circuit

Infiniti J30 1994 - DTC 31: ECM

Turn ignition on. Erase Diagnostic Test Mode II (Self-Diagnostic Results) memory. Perform Diagnostic Test Mode II (Self-Diagnostic Results). If ECM displays DTC 31 again, replace ECM.

Infiniti J30 1994 - DTC 32: EGR FUNCTION (CALIF.) 1) Check Vacuum Source To EGR Valve

Start engine and bring to operating temperature. With engine speed at about 2000 RPM, disconnect vacuum hose to EGR valve. See Fig. 21 . If vacuum is not present, go to next step. If vacuum is present, inspect EGR valve. See SYSTEM & COMPONENT TESTING article. Replace EGR valve if necessary and perform FINAL CHECK.

Fig. 21: Infiniti J30 1994 - Component Locations - DTC 32, Checking Vacuum Source To EGR Valve

Infiniti J30 1994 - 2) Check Control Function

If vacuum is not present, with engine running, measure voltage between ECM terminal No. 102 (Red/Black wire) and ground. At idle, voltage should be zero volts. At 2000 RPM, voltage should be battery voltage. See Fig. 22 . If voltage measured is not as specified, go to next step. If voltage is as specified, inspect vacuum hose for clogging, cracks or proper connection. Repair vacuum hose as necessary.

Fig. 22: Infiniti J30 1994 - Component Locations - DTC 32, Checking Control Function

Infiniti J30 1994 - 3) Check Output Signal Circuit

Turn engine off and disconnect ECM harness connector. Disconnect EGR control solenoid valve harness connector. Verify harness continuity between ECM terminal No. 102 (Red/Black wire) and ground, and between EGR control solenoid valve harness connector terminal "a" (Red/Black wire) and ground. See Fig. 23 and Fig. 24 . If continuity does not exist, go to next step. If there is continuity, repair harness or connectors between ECM and EGR control solenoid valve as necessary.

Fig. 23: Infiniti J30 1994 - Component Locations - Locating EGR Control Solenoid Valve Harness Connector

Fig. 24: Infiniti J30 1994 - Component Locations - DTC 32, Checking Output Signal Circuit

Infiniti J30 1994 - 4) Check Component

Inspect EGR control solenoid valve. See SYSTEM & COMPONENT TESTING article. Replace EGR control solenoid valve if necessary and perform FINAL CHECK.

Infiniti J30 1994 - 5) Check Component Using CONSULT

Turn ignition off and connect CONSULT. Connect ECM harness connector and EGR control solenoid valve harness connector. Turn ignition on. Using CONSULT, perform EGRC SOL/V CIRCUIT in FUNCTION TEST mode. Replace EGR control solenoid valve if necessary.

Another method is to turn EGR and canister control solenoid valve ON and OFF using CONSULT in ACTIVE TEST mode. Replace EGR control solenoid valve if operating sounds are not heard. Perform FINAL CHECK.

Infiniti J30 1994 - DTC 33 (LEFT) & DTC 53:(RIGHT) HEATED OXYGEN SENSOR (HO2S) 1) Check Input Signal Circuit

Turn ignition off and disconnect HO2S harness connector and ECM harness connector. Verify harness continuity between ECM connector terminals No. 29 (right), No. 55 (left) and HO2S connector terminal "b" (White wire). See Fig. 25 , Fig. 26 and Fig. 27 . If continuity is present, go to next step. If continuity is not present, repair harness or connectors as necessary.

Fig. 25: Infiniti J30 1994 - Component Locations - Locating Left HO2S Harness Connector

Fig. 26: Infiniti J30 1994 - Component Locations - Locating Right HO2S Harness Connector

Fig. 27: Infiniti J30 1994 - Component Locations - DTCs 33 & 53, Checking Input Signal Circuit

Infiniti J30 1994 - 2) Check Voltage

Connect HO2S harness connector and ECM harness connector. Bring engine to operating temperature and hold speed at approximately 2000 RPM. Using an analog voltmeter, measure voltage between ECM terminals No. 29 and 55 (White wire) and ground. See Fig. 28 . If voltage measured is approximately .3 volt and there are no voltage fluctuations, replace HO2S. If voltage fluctuates between approximately .2-.9 volt, HO2S is okay. Perform FINAL CHECK.

Fig. 28: Infiniti J30 1994 - Component Locations - DTCs 33 & 53, Checking Voltage

Infiniti J30 1994 - 3) Check Voltage Using CONSULT

Turn ignition off. Connect CONSULT, HO2S harness connector and ECM harness connector. Start engine, bring to operating temperature and hold speed at 2000 RPM. Select DATA MONITOR mode with CONSULT. Touch RECORD. Check O2 SEN (-R) voltage. If voltage displayed is approximately .3 volt and there are no voltage fluctuations, replace HO2S. If voltage displayed fluctuates between approximately .2-.9 volt, HO2S is okay. Perform FINAL CHECK.

Infiniti J30 1994 - DTC 34: KNOCK SENSOR 1) Check Input Signal Circuit I

Turn ignition off. Disconnect ECM harness connector and knock sensor sub-harness connector. Verify harness continuity between knock sensor sub-harness connector terminal "b" (White wire) and ECM terminal No. 23. See Fig. 2 , Fig. 3 , 29and 30. If continuity is present, go to next step. If continuity is not present, repair harness or connectors as necessary.

Infiniti J30 1994 - 2) Check Input Signal Circuit II

Disconnect knock sensor harness connector from sub-harness. Verify harness continuity between sub-harness terminal "c" and knock sensor harness connector terminal "f" (White wire). See Fig. 31 . If continuity is present, go to next step. If continuity is not present, repair harness or connectors as necessary.

Infiniti J30 1994 - 3) Check Component

Inspect knock sensor. See SYSTEM & COMPONENT TESTING article. Replace knock sensor if necessary and perform FINAL CHECK.

Fig. 29: Infiniti J30 1994 - Component Locations - Locating Knock Sensor Sub-Harness Connector

Fig. 30: Infiniti J30 1994 - Component Locations - DTC 34, Checking Input Signal Circuit I

Fig. 31: Infiniti J30 1994 - Component Locations - DTC 34, Checking Input Signal Circuit II

Infiniti J30 1994 - DTC 35: EGR TEMPERATURE SENSOR (CALIF.) 1) Check Power Supply

Turn ignition off and disconnect EGR temperature sensor harness connector. Turn ignition on. Measure voltage between EGR temperature sensor connector terminal "b" (Brown wire) and ground. See Fig. 32 and Fig. 33 . If voltage is approximately 5 volts, go to next step. If voltage is not as specified, repair harness or connectors as necessary.

Fig. 32: Infiniti J30 1994 - Component Locations - Locating EGR Temperature Sensor Connector

Fig. 33: Infiniti J30 1994 - Component Locations - DTC 35, Checking Power Supply

Infiniti J30 1994 - 2) Check Ground Circuit

Turn ignition off. Verify harness continuity between EGR temperature sensor connector terminal "a" (Orange/Blue wire) and engine ground. See Fig. 34 . If continuity is present, go to next step. If continuity is not present, verify harness continuity between EGR temperature sensor terminal "a" and ECM terminal No. 30 (Orange/Blue wire), and between automatic transmission control unit terminal No. 35 (48-pin connector located on driver side kick panel) and EGR temperature sensor terminal "a" (Orange/Blue wire). If continuity is not present, repair harness or connectors as necessary.

Infiniti J30 1994 - 3) Check Component

Inspect EGR temperature sensor. See SYSTEM & COMPONENT TESTING article. Replace EGR temperature sensor if necessary and perform FINAL CHECK.

Fig. 34: Infiniti J30 1994 - Component Locations - DTC 35, Checking Ground Circuit

Infiniti J30 1994 - DTC 42: FUEL TEMPERATURE SENSOR 1) Check Input Signal Circuit

Turn ignition off and disconnect fuel temperature sensor harness connector. Turn ignition on. Measure voltage between terminal "a" (White wire) and ground. If voltage is approximately 5 volts, go to next step. If voltage is not as specified, verify harness continuity in harness and connectors between ECM terminal No. 36 (White wire) and fuel temperature sensor. Repair harness or connectors as necessary. See Fig. 2 , Fig. 3 , Fig. 35 and Fig. 36 .

Infiniti J30 1994 - 2) Check Component

Inspect fuel temperature sensor. See SYSTEM & COMPONENT TESTING article. Replace fuel temperature sensor if necessary and perform FINAL CHECK.

Fig. 35: Infiniti J30 1994 - Component Locations - Locating Fuel Temperature Sensor Harness Connector

Fig. 36: Infiniti J30 1994 - Component Locations - DTC 42, Checking Input Signal Circuit

Infiniti J30 1994 - DTC 43: THROTTLE POSITION SENSOR (TPS) 1) Check Power Supply

Turn ignition off and disconnect TPS harness connector. Turn ignition on. Measure voltage between TPS connector terminal "c" (Green wire) and ground. See Fig. 37 and Fig. 38 . If voltage is approximately 5 volts, go to next step. If voltage is not as specified, repair harness or connectors as necessary.

Fig. 37: Infiniti J30 1994 - Component Locations - Locating TPS Harness Connector

Fig. 38: Infiniti J30 1994 - Component Locations - DTC 43, Checking Power Supply

Infiniti J30 1994 - 2) Check Ground Circuit

Turn ignition off. Verify harness continuity between TPS connector terminal "a" (Orange/Blue wire) and engine ground. See Fig. 39 . If continuity is present, go to next step. If continuity is not present, verify harness continuity between TPS terminal "a" and ECM terminal No. 30 (Orange/Blue wire), and between automatic transmission control unit terminal No. 35 (48-pin connector located on driver side kick panel) and TPS terminal "b" (Orange/Blue wire). If continuity is not present, repair harness or connectors as necessary.

Fig. 39: Infiniti J30 1994 - Component Locations - DTC 43, Checking Ground Circuit

Infiniti J30 1994 - 3) Check Input Signal Circuit

Disconnect ECM harness connector. See Fig. 2 . Verify harness continuity between ECM connector terminal No. 38 and TPS connector terminal "b" (Black wire). See Fig. 3 and Fig. 40 . If continuity is present, go to next step. If continuity is not present, repair harness or connectors as necessary.

Infiniti J30 1994 - 4) Check Component

Inspect TPS. See SYSTEM & COMPONENT TESTING article. Replace TPS if necessary and perform FINAL CHECK.

Fig. 40: Infiniti J30 1994 - Component Locations - DTC 43, Checking Input Signal Circuit

Infiniti J30 1994 - DTC 45: INJECTOR LEAK (CALIF.) 1) Clear Self-Learning Data

Clear self-learning data. Start engine and bring to operating temperature. Stop engine and disconnect Mass Airflow (MAF) sensor connector. Start engine and run for at least 30 seconds at 2000 RPM. See Fig. 41 . Stop engine and connect MAF sensor connector. Ensure DTC 12 is displayed in Diagnostic Test Mode II. Erase self-diagnostic memory. Ensure DTC 55 is displayed in Diagnostic Test Mode II. See ENTERING SELF-DIAGNOSTICS.

Infiniti J30 1994 - 2) Clear Self-Learning Data Using CONSULT

Select SELF-LEARNING CONT in ACTIVE TEST mode with CONSULT. Clear self-learning control coefficient by touching CLEAR.

Fig. 41: Infiniti J30 1994 - Component Locations - DTC 45, Clearing Self-Learning Data

Infiniti J30 1994 - 3) Perform Diagnostic Test Mode II (Self-Diagnostic Results)

IF DTC does not return, inspection is completed. If DTC 45 displays, relieve fuel pressure and remove injector assembly. See REMOVAL, OVERHAUL & INSTALLATION article. Do not remove fuel hose or injectors from injector gallery. Turn ignition on. Ensure fuel does not drip from injector(s). Replace any injector(s) that drip fuel. Perform FINAL CHECK.

Infiniti J30 1994 - DTC 51: INJECTOR (CALIF.) 1) Search For Malfunctioning Circuit

Using a listening device, search for circuit which does not produce injector operating sound at idle. See Fig. 42 .

Infiniti J30 1994 - 2) Search For Malfunctioning Circuit Using CONSULT

Perform POWER BALANCE in ACTIVE TEST mode. Search for circuit which does not produce a momentary engine speed drop.

Fig. 42: Infiniti J30 1994 - Component Locations - DTC 51, Checking For Injector Operating Sound

Infiniti J30 1994 - 3) Check Circuit Continuity I

Turn ignition off. Disconnect EFI sub-harness connectors (Brown and Gray connectors). See Fig. 43 . Verify harness continuity between Brown connector (injector side) terminal "e" (Red/Black wire) and Gray connector terminals "i" (Pink/Black wire), "j" (White wire), "k" (Light Green/Black wire), "l" (Yellow wire), "o" (Gray wire) and "p" (Red/Blue wire). See Fig. 44 . If continuity is not present, go to next step. If continuity is present, go to step 6).

Fig. 43: Infiniti J30 1994 - Component Locations - Locating EFI Harness Connectors

Fig. 44: Infiniti J30 1994 - Component Locations - DTC 51, Checking Circuit Continuity I

Infiniti J30 1994 - 4) Check Circuit Continuity II

Disconnect injector harness connectors. See Fig. 45 . Verify harness continuity between Brown connector (injector side) terminal "e" and each injector harness connector terminal "r" (Red/Black wire). Verify harness continuity between each injector terminal "q" and Gray connector terminals "i" (Pink/Black wire), "j" (White wire), "k" (Light Green/Black wire), "l" (Yellow wire), "o" (Gray wire) and "p" (Red/Blue wire). See Fig. 46 .

Fig. 45: Infiniti J30 1994 - Component Locations - Locating Injector Harness Connector

Fig. 46: Infiniti J30 1994 - Component Locations - DTC 51, Checking Circuit Continuity II

Infiniti J30 1994 - 5) Check Component

Inspect each injector. See SYSTEM & COMPONENT TESTING article. Replace injector(s) if necessary.

Infiniti J30 1994 - 6) Check Output Signal Circuit

Turn ignition off. Disconnect ECM harness connector. Verify harness continuity between ECM harness connector terminals and ECM side of EFI Gray connector terminals as follows:

• ECM terminal No. 101 and EFI terminal "s" (Yellow wire).
• ECM terminal No. 103 and EFI terminal "u" (White wire).
• ECM terminal No. 105 and EFI terminal "w" (Red/Blue wire).
• ECM terminal No. 110 and EFI terminal "t" (Light Green/Black wire).
• ECM terminal No. 112 and EFI terminal "v" (Pink/Black wire).
• ECM terminal No. 114 and EFI terminal "x" (Gray wire).

See Fig. 47 . If continuity is not present, repair harness or connectors as necessary. If continuity is present, inspect ECM pin terminals for damage or check for bad connection of ECM harness connector. Perform FINAL CHECK.

Fig. 47: Infiniti J30 1994 - Component Locations - DTC 51, Checking Output Signal Circuit Continuity

Infiniti J30 1994 - DTC 54: AUTOMATIC TRANSMISSION (A/T) CONTROL Check Input Signal Circuit

Turn ignition off. Disconnect ECM harness connector and A/T control unit harness connector. Verify harness continuity between ECM connector terminal No. 5 and A/T control unit connector terminal No. 10 (Blue/Black wire). Verify harness continuity between ECM connector terminal No. 14 and A/T control unit connector terminal No. 11 (Pink/Blue wire). See Fig. 48 and Fig. 49 . If continuity is present, perform FINAL CHECK. If continuity is not present, check connectors between ECM and A/T control unit. Repair harness or connectors as necessary and perform FINAL CHECK.

Fig. 48: Infiniti J30 1994 - Component Locations - Locating A/T Control Unit Connector

Fig. 49: Infiniti J30 1994 - Component Locations - DTC 54, Checking Input Signal Circuit

Infiniti J30 1994 - SUMMARY

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