Engine Controls - Tests W/codes: Diagnosis Nissan Quest I

SELF-DIAGNOSTIC SYSTEM

Self-diagnostic system is used for diagnosing malfunctions of Electronic Concentrated Control System (ECCS) sensors and actuators. Engine Control Module (ECM) has a number of available diagnostic modes within computer.

Vehicles have 2 modes with subdivisions. Before selecting any mode of self-diagnostics, always perform basic diagnostic procedures listed in BASIC TESTING article in the ENGINE PERFORMANCE section. Doing so prevents wasted time and false diagnostic results.

DIAGNOSTIC MODES

Self-diagnostic system can detect engine control system malfunctions and store related trouble codes. Trouble codes, including intermittent codes, are stored in ECM memory and are available for retrieval unless codes have been cleared.

Self-diagnostic system uses MIL, located in instrument panel, or dual Light Emitting Diodes (LED), located on ECM. See ECM LOCATIONS table. For system application, see SELF-DIAGNOSTIC SYSTEM .

ECM LOCATIONS

Note. For 1994 production, manufacturer adopted California emission control specifications for all vehicles. Refer to Nissan Technical Service Bulletin number NTB93-110A for updated self-diagnostic system information.

Entering Self-Diagnostics

Self-diagnostic system will operate in one of 2 modes. Self-diagnostic system normal operational mode is Mode I. With ignition switch in ON position and engine not running, connect a jumper wire between harness connector terminals "A" (Gray/Blue wire) and "B" (Blue/White wire), wait at least two seconds, and remove. System is now in Mode II. Reconnect harness connectors. (Scheme 10)

Scheme 10

Note. Modes cannot be switched while engine is running. When ignition switch is turned to OFF position while in Mode II, ECM switches to Mode I.

Mode II (Self-Diagnostics)

When Mode II is accessed (engine not running), codes stored in ECM memory will be flashed by MIL (CHECK ENGINE light).

Long flashes (.6 second) indicate first digit of code. Short flashes (.3 second) indicate second digit of code. For example: one long flash followed by 2 short flashes indicate a Code 12.

TROUBLE CODE DEFINITION

Note. Not all trouble codes will activate CHECK ENGINE light.

TROUBLE CODE IDENTIFICATION CHART

DIAGNOSTIC TROUBLE CODE (DTC) TESTS

Note. Procedures using Nissan Consult Tester (J-38465) are provided when available. If circuit test is being performed without Consult tester, use alternate test procedure.

Scheme 11

Scheme 12

DTC 11: CRANKSHAFT POSITION (CKP) SENSOR

1. Check Power Supply - Turn ignition off. Disconnect CKP sensor. (Scheme 13) Turn ignition on. Measure voltage between CKP sensor harness connector terminal "a" (Red/Black wire) and ground. (Scheme 14) If battery voltage is present, go to next step. If battery voltage is not present, repair wiring harness and/or connectors between CKP sensor and ECM.
2. Check Ground Circuit Turn ignition off. Leave CKP sensor harness connector disconnected. Check for continuity between CKP sensor harness connector terminal "d" (Black wire) and ground. If continuity is present, go to next step. If continuity is not present, repair wiring harness and/or connector as necessary.
3. Check Input Signal Circuit Turn ignition off. Disconnect ECM harness connector. (Scheme 11) Check continuity between CKP sensor harness connector terminal "b" (Red/White wire) and ECM harness connector terminals No. 22 and 30 (120 degree signal). (Scheme 12)and (Scheme 15). Check continuity between CKP sensor harness connector terminal "c" (Red/Blue wire) and ECM harness connector terminals No. 31 and 40 (one degree signal). If continuity is present, go to next step. If continuity is not present, repair wiring harness or connectors as necessary.
4. Check Component - Inspect CKP sensor. See I SYS/COMP TESTS article in the ENGINE PERFORMANCE section. If CKP sensor is defective, replace as necessary and perform FINAL CHECK in this article. If CKP sensor is okay, repair ECM pin terminals and/or wiring harness connector.

Scheme 13

Scheme 14

Scheme 15

DTC 12: MASS AIRFLOW (MAF) SENSOR

1. Check Power Supply - Turn ignition on. Disconnect MAF wiring harness connector. (Scheme 16) Measure voltage between MAF sensor harness connector terminal "a" (Red/Black wire) and ground. (Scheme 17) If battery voltage is present, go to next step. If battery voltage is not present, repair harness or connectors as necessary.
2. Check Ground Circuit - Turn ignition off. Disconnect MAF sensor harness connector. (Scheme 16) Check continuity between MAF sensor wiring harness connector terminal "b" (Orange/Blue wire) and ECM terminal No. 17. (Scheme 12)and (Scheme 18). If continuity is present, go to next step. If continuity is not present, repair wiring harness or connectors as necessary.
3. Check Input Circuit - Turn ignition off. Disconnect ECM and MAF sensor wiring harness connector. (Scheme 11)and (Scheme 16). Check continuity between MAF harness connector terminal "c" (White/Blue wire) and ECM harness connector terminal No. 16. (Scheme 12)and (Scheme 19). If continuity is not present, repair harness or connectors as necessary. If continuity is present, go to next step.
4. Check MAF Sensor - Inspect MAF sensor. See I SYS/COMP TESTS article in the ENGINE PERFORMANCE section. Replace MAF sensor if necessary and perform «FINAL CHECK»(ref-17397-S33636928272000122900000) in this article. If MAF sensor is okay, repair ECM pin terminals and/or wiring harness connector.

Scheme 16

Scheme 17

Scheme 18

Scheme 19

DTC 13: ENGINE COOLANT TEMPERATURE (ECT) SENSOR

1. Check Power Supply - Turn ignition off. Disconnect ECT sensor harness connector. (Scheme 20) Turn ignition on. Measure voltage between ECT sensor harness connector terminal "a" (Green/Red wire) and ground. (Scheme 21) If voltage is about 5 volts, go to next step. If voltage is not about 5 volts, repair harness or connectors as necessary.
2. Check Ground Circuit - Turn ignition off. Check continuity between terminal "b" (White/Black wire) and engine ground. (Scheme 22) If continuity is present, go to next step. If continuity is not present, repair harness or connectors as necessary.
3. Check Component - Inspect ECT sensor. See I SYS/COMP TESTS article in the ENGINE PERFORMANCE section. Replace ECT sensor if necessary and perform «FINAL CHECK»(ref-17397-S33636928272000122900000) in this article. If ECT sensor is okay, repair ECM pin terminals and/or wiring harness connector.

Scheme 20

Scheme 21

Scheme 22

DTC 14: VEHICLE SPEED SENSOR (VSS)

1. Check Speedometer Operation - Ensure speedometer operates properly. If speedometer operates properly, go to next step. If speedometer does not operate properly, check vehicle speed sensor. See appropriate VEHICLE SPEED SENSOR testing procedure under ENGINE SENSORS & SWITCHES in appropriate I SYS/COMP TESTS article in the ENGINE PERFORMANCE section. Repair or replace as necessary.
2. Check Input Signal Circuit - Turn ignition off. Disconnect ECM and combination meter wiring harness connector. (Scheme 11) Check harness continuity between ECM terminal No. 32 and combination meter terminal "j" (Green/Yellow wire). (Scheme 12)and (Scheme 13). If continuity is present, repair ECM pin terminals and/or wiring harness connector. If continuity is not present, repair wiring harness or connectors between ECM and combination meter.

Scheme 23

DTC 21: IGNITION SIGNAL

1. Check Power Supply - Turn ignition off. Disconnect ignition coil harness connector. (Scheme 24) Turn ignition on. Measure voltage between ignition coil harness connector terminal "a" (White/Red wire) and ground. (Scheme 26) If battery voltage is not present, repair wiring harness and/or connectors between ignition coil and ignition switch. If battery voltage is present, go to next step.
2. Check Ground Circuit - Turn ignition off. Disconnect power transistor harness connector. (Scheme 24) Disconnect resistor/condenser harness connector. (Scheme 25) Check continuity between ignition coil connector terminal "b" (Green wire) and following: power transistor connector terminal "i" (Green wire) and resistor/condenser connector terminal "d" (Green wire). (Scheme 27) Check continuity between power transistor connector terminal "h" (Black wire) and engine ground. (Scheme 28) If continuity is present, go to next step. If continuity is not present, repair harness or connectors as necessary.
3. Check Input Signal Circuit - Turn engine off. Leave power transistor and resistor/condenser wiring harness disconnected. Disconnect ECM harness connector. (Scheme 11) Check continuity between resistor/condenser wiring harness connector terminal "c" (Red wire) and ECM connector terminal No. 3. (Scheme 12)and (Scheme 29). If continuity is present, go to next step. If continuity is not present, repair harness or connectors as necessary.
4. Check Output Signal Circuit - Ensure ignition is off. Check for continuity between ECM terminal No. 1 and power transistor connector terminal "g" (Blue wire). (Scheme 12)and (Scheme 30). If continuity is not present, repair harness or connectors as necessary. If continuity is present, go to next step.
5. Check Components - Inspect ignition coil, power transistor and resistor and condenser. See I SYS/COMP TESTS article in the ENGINE PERFORMANCE section. Repair or replace components if necessary and perform «FINAL CHECK»(ref-17397-S33636928272000122900000) in this article. If components are okay, repair ECM pin terminals and/or wiring harness connector.

Scheme 24

Scheme 25

Scheme 26

Scheme 27

Scheme 28

Scheme 29

Scheme 30

DTC 31: ECM

Turn ignition on. Erase self-diagnostic test Mode II memory. Perform self-diagnostic test Mode II. If ECM displays DTC 31 again, replace ECM.

DTC 32: EGR FUNCTION

Note. DO NOT perform this test if DTC 12 is present.

1. Check Vacuum Source To EGR Valve - Start engine and warm to operating temperature. Disconnect hose from EGR valve and check vacuum. Vacuum should not be present. Raise engine speed to about 2000 RPM and check vacuum. Vacuum should be present. If vacuum is not as specified, go to next step. If vacuum is as specified, inspect EGR system. See I SYS/COMP TESTS article in the ENGINE PERFORMANCE section. Repair or replace as necessary and perform «FINAL CHECK»(ref-17397-S33636928272000122900000) in this article.
2. Check Control Function - If vacuum is not present at about 2000 RPM, measure voltage between ECM terminal No. 102 (Gray wire) and ground. (Scheme 12)and (Scheme 31). At idle, voltage should be about zero volts. At 2000 RPM, voltage should be battery voltage. If voltage 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.
3. Check Power Supply - Turn ignition off. Disconnect EGR control solenoid valve wiring harness connector. Turn ignition on. Measure voltage between harness connector terminal "a" (White/Red wire) and ground. (Scheme 32) If battery voltage is present, go to next step. If battery voltage is not present, check wiring harness and harness connectors between EGR control solenoid and ignition switch. Repair or replace as necessary.
4. Check Output Signal Circuit - Turn engine off. Leave ECM disconnected. Check continuity between ECM terminal No. 102 and EGR control solenoid valve wiring harness connector terminal "b" (Gray wire) (Scheme 12)and (Scheme 33). If continuity is present, go to next step. If continuity is not present, repair harness or connectors EGR control solenoid valve and ignition switch.
5. Check Component - Inspect EGR control solenoid valve. See I SYS/COMP TESTS article in the ENGINE PERFORMANCE section. On California models, measure resistance of EGR temperature sensor. See I - SYS/COMP TESTS article in the ENGINE PERFORMANCE section. Repair or replace components as necessary and perform «FINAL CHECK»(ref-17397-S33636928272000122900000) in this article. If components are okay, repair ECM pin terminals and/or wiring harness connector.

Scheme 31

Scheme 32

Scheme 33

DTC 33: OXYGEN SENSOR

1. Check System Function - Start engine and allow to warm to operating temperature. Raise engine speed to about 2000 RPM with no load for 2 minutes. Enter self-diagnostic test Mode II. With engine speed at about 2000 RPM, Malfunction Indicator Light (MIL) should blink on and off more than 5 times in 10 seconds. If MIL is as specified, system is okay and testing is complete. If MIL is not as specified, go to step 3).
2. Check System Function Using Consult Tester (J-38465) - Start engine and allow to warm to operating temperature. Raise engine speed to about 2000 RPM with no load for 2 minutes. With engine speed at about 2000 RPM, ensure M/R F/C MNT in DATA MONITOR mode indicates RICH and LEAN periodically more than 5 times in 10 seconds. If conditions are as specified, system is okay and testing is complete. If conditions are not as specified, go to next step.
3. Check Power Supply - Turn ignition off. Disconnect oxygen sensor harness connector. (Scheme 34) Turn ignition on. Check voltage between oxygen sensor terminal "c" (Blue/Yellow wire) and ground. (Scheme 35) If battery voltage is present, go to next step. If battery voltage is not present, check 10-amp fuse, wiring harness and connectors between oxygen sensor and ignition switch.
4. Check Ground Circuit - Turn ignition off. Check continuity between oxygen sensor wiring harness connector terminal "a" (Black wire) and ground. (Scheme 36) If continuity is present, go to next step. If continuity is not present, repair harness or connectors between oxygen sensor and ground.
5. Check Input Signal - Turn ignition off. Ensure oxygen sensor and ECM are disconnected. Check continuity between oxygen sensor terminal "b" (Green/Black wire) and ECM terminal No. 19. (Scheme 12)and (Scheme 37). If continuity is not present, repair harness or connectors as necessary. If continuity is present, replace oxygen sensor and perform «FINAL CHECK»(ref-17397-S33636928272000122900000) in this article.

Scheme 34

Scheme 35

Scheme 36

Scheme 37

DTC 34: KNOCK SENSOR

Note. The knock sensor has a sub-harness assembly. This test is performed at the wiring harness-to-sub-harness connector.

1. Check Input Signal Circuit - Turn ignition off. Disconnect ECM wiring harness connector and knock sensor sub-harness connector. (Scheme 11)and (Scheme 38). Check continuity between wiring harness connector terminal "a" (White wire) and ECM terminal No. 27 (White wire). (Scheme 12)and (Scheme 39). If continuity is present, go to next step. If continuity is not present, repair harness or connectors as necessary.
2. Check Component - Inspect knock sensor. See I SYS/COMP TESTS article in the ENGINE PERFORMANCE section. Replace knock sensor if necessary and perform «FINAL CHECK»(ref-17397-S33636928272000122900000) in this article. If knock sensor is okay, repair ECM pin terminals and/or wiring harness connector.

Scheme 38

Scheme 39

DTC 35: EGR TEMPERATURE SENSOR

1. Check Power Supply - Disconnect EGR temperature sensor wiring harness connector. (Scheme 40) Turn ignition on. Measure voltage between EGR temperature sensor wiring harness connector terminal "a" (White/Red wire) and ground. (Scheme 41) If voltage is about 5 volts, go to next step. If voltage is not about 5 volts, repair wiring harness or connectors between ECM and EGR temperature sensor.
2. Check Ground Circuit - Turn ignition off. Check continuity between EGR temperature sensor wiring harness connector terminal "b" (White/Black wire) and engine ground. (Scheme 42) If continuity is present, go to next step. If continuity is not present, repair wiring harness and/or connectors between ECM and EGR temperature sensor.
3. Check Component - Inspect EGR temperature sensor. See I SYS/COMP TESTS article in the ENGINE PERFORMANCE section. Replace EGR temperature sensor if necessary and perform «FINAL CHECK»(ref-17397-S33636928272000122900000) in this article. If EGR temperature sensor is okay, repair ECM pin terminals and/or wiring harness connector.

Scheme 40

Scheme 41

Scheme 42

DTC 43: THROTTLE POSITION (TP) SENSOR

1. Check Power Supply - Turn ignition off. Disconnect TP sensor harness connector. (Scheme 43) Turn ignition on. Measure voltage between TP sensor connector terminal "c" (Brown wire) and ground. (Scheme 44) If voltage is about 5 volts, go to next step. If voltage is not as specified, repair harness or connectors as necessary.
2. Check Ground Circuit - Turn ignition off. Check continuity between TP sensor connector terminal "a" (White/Black wire) and engine ground. (Scheme 45) If continuity is present, go to next step. If continuity is not present, repair harness or connectors as necessary.
3. Check Input Signal Circuit - Disconnect ECM harness connector. (Scheme 11) Ensure continuity exists between ECM connector terminal No. 20 and TP sensor connector terminal "b" (Red wire). (Scheme 12)and (Scheme 46). If continuity is present, go to next step. If continuity is not present, repair harness or connectors as necessary.
4. Check Component - Inspect TP sensor. See I SYS/COMP TESTS article in the ENGINE PERFORMANCE section. Replace TP sensor if necessary and perform «FINAL CHECK»(ref-17397-S33636928272000122900000) in this article. If TP sensor is okay, repair ECM pin terminals and/or wiring harness connector.

Scheme 43

Scheme 44

Scheme 45

Scheme 46

DTC 45: INJECTOR LEAK

1. System Check - Turn ignition off. Start engine. Raise engine speed to about 2000 RPM for 30 seconds. Turn ignition off and enter self-diagnostic test Mode II. Ensure Malfunction Indicator Light (MIL) does not come on during testing. If MIL comes on, repair ECM pin terminals and/or wiring harness connector. If MIL does come on, go to next step.
2. Release fuel pressure. Remove fuel injector assembly. See N REMOVE/INSTALL/OHAUL article in the ENGINE PERFORMANCE section. Turn ignition on. Ensure fuel does not drip from injector(s). Repair or replace injector(s) as necessary. Perform «FINAL CHECK»(ref-17397-S33636928272000122900000) in this article. If all fuel injectors are okay, repair ECM pin terminals and/or wiring harness connector.

DTC 51: INJECTOR CIRCUIT

1. Check Control Function - For California models, go to step 2). Start engine. Measure voltage between engine ground and following ECM terminals. (Scheme 12) No. 101 For No. 1 Cylinder No. 103 For No. 3 Cylinder No. 105 For No. 5 Cylinder No. 110 For No. 2 Cylinder No. 112 For No. 4 Cylinder No. 114 For No. 6 Cylinder If battery voltage is present at each terminal, injector circuit is okay. If battery voltage is not present at each terminal, go to next step.
2. Check Power Supply - Turn ignition off. Disconnect sub-harness connectors for injectors No. 1, 3 and 5. Disconnect wiring harness connector for fuel injectors No. 2, 4 and 6. (Scheme 47) Turn ignition on. Measure voltage between following terminals. (Scheme 48) Fuel injector wiring harness connector terminal "a" (Yellow wire) and ground. Fuel injector sub-harness connector terminal "d" (Yellow wire) and ground. ECM wiring harness connector terminal 46 (Yellow wire) and ground. (Scheme 12) If battery voltage is present, go to next step. If battery voltage is not present, repair open or short circuit in wiring harness or blown 25-amp fusible link.
3. Check Output Signal - Turn ignition off. Disconnect ECM wiring harness connector. (Scheme 11) For fuel injectors No. 2, 4 and 6, check continuity between following terminals. (Scheme 49) Fuel injector wiring harness connector terminal "b" and ECM connector terminals No. 110, 112 and 114. For fuel injectors No. 1, 3 and 5, check continuity between following terminals. (Scheme 49) ECM connector terminal No. 101 and fuel injector wiring harness connector terminal "b". ECM connector terminal No. 103 and fuel injector wiring harness connector terminal "c". ECM connector terminal No. 105 and fuel injector wiring harness connector terminal "g". If continuity is present, circuit is okay. Go to next step. If continuity is not present, repair harness or connectors as necessary.
4. Check Component - Release fuel pressure. Remove fuel injector assembly. See N REMOVE/INSTALL/OHAUL article in the ENGINE PERFORMANCE section. Inspect fuel injectors. See I - SYS/COMP TESTS article in the ENGINE PERFORMANCE section. Replace fuel injector(s) if necessary and perform «FINAL CHECK»(ref-17397-S33636928272000122900000) in this article. If all fuel injectors are okay, repair ECM pin terminals and/or wiring harness connector.

Scheme 47

Scheme 48

Scheme 49