Engine Controls - System/component Tests: Diagnosis Nissan Quest I

System Test (VG30E)

1. Start engine and bring to normal operating temperature. Race engine a few times under no-load condition while observing power valve actuator rod. If power valve actuator rod does not move, go to next step. If power valve actuator rod moves, system is functioning properly at this time.
2. With engine running, measure voltage between ECM terminal No. 8 (Orange wire) and ground. With accelerator pedal released, battery voltage should be present. With accelerator pedal depressed, approximately one volt should be present. If voltage is not as specified, go to next step. If voltage is as specified, check actuator vacuum hose for damage and proper installation. Repair hose as necessary. Check surge tank for cracks or holes and repair as necessary. Check one-way valve for air leakage and repair as necessary.
3. Turn ignition off. Disconnect and inspect power valve control solenoid harness connector. Repair connector as necessary. Turn ignition on. Measure voltage between solenoid harness connector White/Blue wire and ground. Battery voltage should be present. If battery voltage is not present, turn ignition off and go to next step. If battery voltage is present, turn ignition off and go to step 5).
4. Disconnect one-pin connector containing White/Red wire at positive terminal of battery. Check continuity between White/Red wire of one-pin battery connector and solenoid harness connector White/Blue wire. Continuity should exist. If continuity does not exist, check Brown fusible link located in fusible link box next to battery. Check White/Blue wire between fusible link and solenoid harness connector for open or short. Repair circuit as necessary.
5. Disconnect and inspect ECM harness connector for pushed-out, bent, damaged or corroded terminals. Repair connector as necessary. Check continuity of Orange wire between ECM terminal No. 8 and solenoid harness connector. Continuity should exist. If continuity does not exist, repair open or short in Orange wire. If continuity exists, check operation of power valve control solenoid. See CONTROL SOLENOID under «POWER VALVE (MAXIMA)»(ref-17400-S40021116252000122900000) .

System Test (VE30DE)

1. Start engine and bring to normal operating temperature. With engine running, measure voltage between ECM terminal No. 8 (Yellow/Black wire) and ground. With accelerator pedal released, battery voltage should be present. With accelerator pedal depressed, approximately zero volts should be present. If voltage is not as specified, go to next step. If voltage is as specified, system is functioning properly at this time.
2. Turn ignition off. Disconnect and inspect power valve control solenoid harness connector. Repair connector as necessary. Turn ignition on. Measure voltage between solenoid harness connector Red/Black wire and ground. Battery voltage should be present. If battery voltage is present, turn ignition off and go to next step. If battery voltage is not present, repair harness or connectors as necessary.
3. Disconnect and inspect ECM harness connector for pushed-out, bent, damaged or corroded terminals. Repair connector as necessary. Check continuity of Yellow/Black wire between ECM terminal No. 8 and solenoid harness connector. Continuity should exist. If continuity does not exist, repair harness or connectors as necessary. If continuity exists, check operation of power valve control solenoid. See CONTROL SOLENOID under «POWER VALVE (MAXIMA)»(ref-17400-S40021116252000122900000) .

System Test

1. Start engine and bring to normal operating temperature. Turn ignition off. After a few seconds, disconnect vacuum hose to swirl control valve actuator. Actuator is located near flywheel end of intake manifold. Restart engine and check vacuum at disconnected hose.
2. On Pickup, vacuum should exist at less than 3600 RPM and not exist at more than 3600 RPM. On 240SX, vacuum should exist at less than 2400 RPM and not exist at more than 2400 RPM. On all models, if vacuum does not exist as specified, leave engine running and go to next step. If vacuum exists as specified, system is functioning properly at this time.
3. On Pickup, measure voltage between ECM terminal No. 12 (Gray wire) and ground. On 240SX, measure voltage between ECM terminal No. 25 (Gray wire) and ground. On Pickup, zero volts should exist at less than 3600 RPM and battery voltage should exist at more than 3600 RPM. On 240SX, zero volts should exist at less than 2400 RPM and battery voltage should exist at more than 2400 RPM.
4. On all models, if voltage is as specified, check vacuum hose and swirl control valve for clogging, cracks and proper connection and repair as necessary. If voltage is not as specified, turn ignition off. Disconnect and inspect swirl control valve solenoid connector, located under intake manifold on Pickup or rear of cylinder head on 240SX. Repair connector as necessary.
5. Turn ignition on. Measure voltage between solenoid connector Black/White wire (Pickup) or Brown wire (240SX) and ground. Battery voltage should exist. If battery voltage exists, go to next step. If battery voltage does not exist, check harness, connectors and fuse. Repair as necessary.
6. Turn ignition off. Disconnect and inspect ECM harness connector for pushed-out, bent, damaged or corroded terminals. Repair connector as necessary. Check continuity of Gray wire between ECM terminal No. 12 (Pickup) or terminal No. 25 (240SX) and solenoid harness connector. Continuity should exist. If continuity does not exist, repair harness or connector as necessary. If continuity exists, check operation of swirl control valve solenoid. See CONTROL SOLENOID under «SWIRL CONTROL VALVE»(ref-17400-S31138194142000122900000) .

FAIL-SAFE SYSTEM TEST (MAXIMA VG30E)

Disconnect crankshaft position sensor and attempt to start engine. If engine begins to run in a few seconds, system is functioning properly. If engine does not begin to run in a few seconds, failure to start may not be caused by crankshaft position sensor. Determine cause of problem using TESTS W/O CODES article.

FAIL-SAFE SYSTEM DIAGNOSIS (MAXIMA VG30E)

1. Turn ignition on. Perform MODE III (SELF-DIAGNOSTICS) under DUAL LED SYSTEM in «TESTS W/CODES»(ref-17392) article. If Code 11 is present, check crankshaft position sensor. See CRANKSHAFT POSITION SENSOR under «ENGINE SENSORS & SWITCHES»(ref-17400-S25539335572000122900000) . After making repairs, start engine to ensure CHECK ENGINE light is off.
2. If Code 11 is not present but CHECK ENGINE light is on, try to enter MODE III again. If unable to enter MODE III, replace ECM. If MODE III is entered and Code 11 is not present, check for short in CHECK ENGINE light circuit causing light to stay on.

CLOSED THROTTLE POSITION SWITCH SYSTEM TEST (MAXIMA VG30E)

1. Turn ignition on. Perform MODE IV (Switch Check) under DUAL LED SYSTEM in TESTS W/CODES article. Red LED on ECM should turn on and off as accelerator pedal is depressed and released. If Red LED does not function as described, go to next step. If Red LED functions as described, system is functioning properly.
2. Turn ignition off. Disconnect and inspect closed throttle position switch harness connector for pushed-out, bent, damaged or corroded terminals. Repair connector as necessary. Disconnect and inspect ECM harness connector for pushed-out, bent, damaged or corroded terminals. Repair connector as necessary.
3. Check continuity of Green/Red wire between ECM terminal No. 54 and closed throttle position switch harness connector. Continuity should exist. Check continuity of Green/Yellow wire between ECM terminal No. 57 and closed throttle position switch harness connector. Continuity should exist.
4. If continuity does not exist, repair harness or connectors as necessary. If continuity exists, check closed throttle position switch for proper installation. See «SPECIFICATIONS»(ref-17386) article. If switch is installed properly, test switch. See CLOSED THROTTLE POSITION SWITCH TEST under «ENGINE SENSORS & SWITCHES»(ref-17400-S25539335572000122900000) .

CLOSED THROTTLE POSITION SWITCH SYSTEM TEST (MAXIMA VE30DE)

1. Start engine. Measure voltage between ECM terminal No. 54 (Green/Orange wire) and ground. Depress accelerator pedal. Voltage should be approximately zero volts. Release accelerator pedal. Battery voltage should be present. If voltage is not as specified, go to next step. If is as specified, system is functioning properly.
2. Turn ignition off. Disconnect and inspect closed throttle position switch harness connector for pushed-out, bent, damaged or corroded terminals. Repair connector as necessary. Check continuity between Green/Orange wire and ground. Continuity should exist. If continuity does not exist, repair harness or connector as necessary. If continuity exists, check closed throttle position switch for proper installation. See «SPECIFICATIONS»(ref-17386) article. If switch is installed properly, test switch. See CLOSED THROTTLE POSITION SWITCH TEST under «ENGINE SENSORS & SWITCHES»(ref-17400-S25539335572000122900000) . If switch is okay, inspect ECM harness connector for pushed-out, bent, damaged or corroded terminals. Repair connector as necessary.

CLOSED THROTTLE POSITION SWITCH SYSTEM TEST (PATHFINDER & PICKUP VG30E)

1. Turn ignition off. Disconnect and inspect closed throttle position switch harness connector for pushed-out, bent, damaged or corroded terminals. Repair connector as necessary. Turn ignition on. Measure voltage between Pink wire and ground. Battery voltage should be present. If battery voltage is present, go to next step. If battery voltage is not present, repair harness or connector as necessary.
2. Turn ignition off. Check continuity between Blue/Yellow wire and ground. Continuity should exist. If continuity does not exist, repair harness or connector as necessary. If continuity exists, check closed throttle position switch for proper installation. Refer to «SPECIFICATIONS»(ref-17386) article. If switch is installed properly, test switch. See CLOSED THROTTLE POSITION SWITCH TEST under «ENGINE SENSORS & SWITCHES»(ref-17400-S25539335572000122900000) . If switch is okay, inspect ECM harness connector for pushed-out, bent, damaged or corroded terminals. Repair connector as necessary.

CLOSED THROTTLE POSITION SWITCH SYSTEM TEST (QUEST)

1. Start engine. Measure voltage between ECM terminal No. 33 (Brown/Yellow wire) and ground. Depress accelerator pedal. Voltage should be approximately zero volts. Release accelerator pedal. Voltage should be 8-10 volts. If voltage is not as specified, go to next step. If is as specified, system is functioning properly.
2. Turn ignition off. Disconnect and inspect closed throttle position switch harness connector for pushed-out, bent, damaged or corroded terminals. Repair connector as necessary. Turn ignition on. Measure voltage between Brown/Yellow wire. Voltage should be 8-10 volts. If voltage is as specified, go to next step. If voltage is not as specified, repair harness or connectors as necessary.
3. Turn ignition off. Check continuity between Red/Yellow wire and ground. Continuity should exist. If continuity does not exist, repair harness or connector as necessary. If continuity exists, check closed throttle position switch for proper installation. Refer to «SPECIFICATIONS»(ref-17386) article. If switch is installed properly, test switch. See CLOSED THROTTLE POSITION SWITCH TEST under «ENGINE SENSORS & SWITCHES»(ref-17400-S25539335572000122900000) . If switch is okay, inspect ECM harness connector for pushed-out, bent, damaged or corroded terminals. Repair connector as necessary.

CLOSED THROTTLE POSITION SWITCH SYSTEM TEST (300ZX)

1. Turn ignition on. Measure voltage between ECM terminal No. 54 (Light Green/Red wire) and ground. Depress accelerator. Voltage should be approximately zero volts. Release accelerator pedal. Voltage should be 9-10 volts. If voltage is not as specified, go to next step. If voltage is as specified, system is functioning properly.
2. Turn ignition off. Disconnect and inspect closed throttle position switch harness connector for pushed-out, bent, damaged or corroded terminals. Repair connector as necessary. Disconnect and inspect ECM harness connector for pushed-out, bent, damaged or corroded terminals. Repair connector as necessary.
3. Check continuity of Light Green/Red wire between ECM terminal No. 54 and closed throttle position switch harness connector. Continuity should exist. Check continuity of Green/Red wire between ECM terminal No. 57 and closed throttle position switch harness connector. Continuity should exist.
4. If continuity does not exist, repair harness or connectors as necessary. If continuity exists, check closed throttle position switch for proper installation. See «SPECIFICATIONS»(ref-17386) article. If switch is installed properly, test switch. See CLOSED THROTTLE POSITION SWITCH TEST under «ENGINE SENSORS & SWITCHES»(ref-17400-S25539335572000122900000) .

CLOSED THROTTLE POSITION SWITCH TEST

Check continuity between specified wire terminals of switch connector. See CLOSED THROTTLE POSITION SWITCH TEST table. There should be continuity with throttle valve fully closed, and no continuity with throttle valve off idle position. If continuity is not as specified, adjust switch. See SPECIFICATIONS article. If switch is adjusted properly, replace switch.

CLOSED THROTTLE POSITION SWITCH TEST

INHIBITOR SWITCH SYSTEM TEST (ALTIMA)

1. Ensure inhibitor switch functions properly. See INHIBITOR SWITCH TEST (ALTIMA, NX 2.0L, SENTRA 2.0L, QUEST & 240SX). Disconnect and inspect ECM harness connector for pushed-out, bent, damaged or corroded terminals. Repair connector as necessary. Turn ignition on. Check continuity between ECM harness connector terminal No. 35 (Green/Orange wire) and ground. Move shift lever through gears. Continuity should exist ONLY in Park and Neutral. If continuity is not as specified, go to next step. If continuity is as specified, system is functioning properly.
2. Turn ignition off. Disconnect inhibitor relay. Relay is located in relay box next to battery. Place shift lever in Neutral or Park. Turn ignition on. Measure voltage between inhibitor relay connector terminal No. 1 and ground. For terminal identification see scheme 3 Battery voltage should be present. If battery voltage is present, go to step 5). If battery voltage is not present, go to next step.
3. Turn ignition off. Disconnect and inspect inhibitor switch 8-pin harness connector for pushed-out, bent, damaged or corroded terminals. Repair connector as necessary. Connector is located on side of transaxle. Turn ignition on. Measure voltage between inhibitor switch 8-pin harness connector terminal No. 3 and ground. For terminal identification see scheme 3 Battery voltage should be present. If battery voltage is present, go to next step. If battery voltage is not present, check harness and connectors for open. Also check 10-amp fuse. Repair as necessary.
4. Turn ignition off. Check continuity between inhibitor relay connector No. 1 and inhibitor switch 8-pin harness connector terminal No. 6. Check continuity between inhibitor relay connector No. 1 and inhibitor switch 8-pin harness connector terminal No. 4. For terminal identification see scheme 3 Continuity should exist in both checks. If continuity does not exist, check harness and connectors for open. Repair as necessary. If continuity exists, check inhibitor switch. See INHIBITOR SWITCH TEST (ALTIMA, NX 2.0L, SENTRA 2.0L, QUEST & 240SX).
5. Turn ignition off. On vehicles equipped with cruise control, check continuity between inhibitor relay connector No. 2 and ground. Check continuity between inhibitor relay connector No. 7 and ground. On vehicles without cruise control, check continuity between inhibitor relay connector No. 2 and ground. Check continuity between inhibitor relay connector No. 5 and ground. For terminal identification see scheme 3 Continuity should exist in all checks. If continuity does not exist in any check, repair open in harness or connectors. If continuity exists in all checks, go to next step.
6. On vehicles equipped with cruise control, check continuity between ECM harness connector terminal No. 35 (Green/Orange wire) and inhibitor relay connector No. 6. On vehicles without cruise control, check continuity between ECM harness connector terminal No. 35 (Green/Orange wire) and inhibitor relay connector No. 3. For terminal identification see scheme 3 Continuity should exist in all checks. If continuity does not exist in any check, repair open in harness or connectors. If continuity exists in all checks, check inhibitor relay. See «RELAYS»(ref-17400-S12256886262000122900000) under RELAYS & SOLENOIDS.

Scheme 50

INHIBITOR SWITCH TEST (ALTIMA, NX 2.0L, SENTRA 2.0L, QUEST & 240SX)

1. Disconnect and inspect inhibitor switch 8-pin and 2-pin harness connectors for pushed-out, bent, damaged or corroded terminals. Repair connector(s) as necessary. Connectors are located on side of transmission. Check continuity across terminals of inhibitor switch 2-pin connector. Continuity should exist ONLY in Park and Neutral. If continuity exists in any other position, replace inhibitor switch.
2. Using INHIBITOR SWITCH CONTINUITY (ALTIMA, NX 2.0L, SENTRA 2.0L, QUEST & 240SX) table, place shift lever in indicated position. Check continuity between terminals of inhibitor switch 8-pin connector listed in table. (Scheme 51) If switch does not function as indicated, replace switch.

INHIBITOR SWITCH CONTINUITY (ALTIMA, NX 2.0L, SENTRA 2.0L, QUEST & 240SX)

Scheme 51

INHIBITOR SWITCH SYSTEM TEST (MAXIMA VG30E)

1. Turn ignition off. Disconnect and inspect inhibitor switch 4-pin (contains Green/Black and Brown wires) harness connectors for pushed-out, bent, damaged or corroded terminals. Repair connector as necessary. Connector is located at right top of bellhousing. Turn ignition on. Measure voltage between Green/Black wire of inhibitor switch 4-pin connector and ground. Battery voltage should be present.
2. If battery voltage is present, go to next step. If battery voltage is not present, turn ignition off. Check continuity between Green/Black wire of inhibitor switch harness connector and device side of 10-amp ENG CONT fuse. Continuity should exist. If continuity does not exist, check harness and connectors for open. Repair as necessary.
3. Turn ignition off. Disconnect and inspect ECM harness connector for pushed-out, bent, damaged or corroded terminals. Repair connector as necessary. Check continuity between ECM harness connector terminal No. 44 (Brown wire) and Brown wire of inhibitor switch 4-pin connector. Continuity should exist. If continuity does not exist, check harness and connectors for open. Repair as necessary. If continuity exists, check inhibitor switch. See INHIBITOR SWITCH TEST (MAXIMA VG30E).

INHIBITOR SWITCH TEST (MAXIMA VG30E)

Disconnect and inspect inhibitor switch 4-pin (contains Green/Black and Brown wires) harness connectors for pushed-out, bent, damaged or corroded terminals. Repair connector as necessary. Connector is located at top right of bellhousing. Check continuity between Green/Black wire and Brown wire of inhibitor switch 4-pin connector. Continuity should exist ONLY in Park and Neutral. If continuity exists in any other position, replace inhibitor switch.

INHIBITOR SWITCH TEST (MAXIMA VE30DE, PICKUP & 300ZX)

Disconnect and inspect inhibitor switch 8-pin harness connectors for pushed-out, bent, damaged or corroded terminals. Repair connector as necessary. Connector is located on top of transaxle (Maxima) or on right side of engine (Pickup) or on left side of transmission (300ZX). Using INHIBITOR SWITCH CONTINUITY (MAXIMA VE30DE, PICKUP & 300ZX) table, check continuity between indicated pins of inhibitor switch 8-pin connector. (Scheme 52) If continuity does not exist as indicated, replace switch.

INHIBITOR SWITCH CONTINUITY (MAXIMA VE30DE, PICKUP & 300ZX)

Scheme 52

INHIBITOR SWITCH SYSTEM TEST (NX 1.6L & SENTRA 1.6L)

1. Turn ignition off. Disconnect and inspect ECM harness connector for pushed-out, bent, damaged or corroded terminals. Repair connector as necessary. Check continuity between ECM harness connector terminal No. 35 (Green/Orange wire) and ground. Move shift lever through gears. Continuity should exist only in Neutral and Park. If continuity exists as specified, go to next step. If continuity does not exist as specified, check harness and connectors for open. Repair as necessary.
2. Disconnect and inspect inhibitor switch 4-pin harness connector for pushed-out, bent, damaged or corroded terminals. Repair connector as necessary. Connector is located side of transaxle. Check continuity between Black wire of inhibitor switch 4-pin harness connector and ground. Continuity should exist. If continuity exists, go to next step. If continuity does not exist, check harness and connectors for open. Repair as necessary.
3. Check continuity between ECM harness connector terminal No. 35 (Green/Orange wire) and Brown/White wire of inhibitor switch 4-pin harness connector. Continuity should exist. If continuity exists, check inhibitor switch. See INHIBITOR SWITCH TEST (NX 1.6L & SENTRA 1.6L). If continuity does not exist, check harness and connectors for open.

INHIBITOR SWITCH TEST (NX 1.6L & SENTRA 1.6L)

Disconnect and inspect inhibitor switch 4-pin harness connectors for pushed-out, bent, damaged or corroded terminals. Repair connector as necessary. Connector is located side of transaxle. Check continuity between inhibitor switch connector terminals No. 1 and 2. (Scheme 53) Continuity should exist ONLY in Park and Neutral. If continuity exists in any other position, replace inhibitor switch.

Scheme 53

INHIBITOR SWITCH SYSTEM TEST (NX 2.0L & SENTRA 2.0L)

1. Turn ignition off. Disconnect and inspect ECM harness connector for pushed-out, bent, damaged or corroded terminals. Repair connector as necessary. Turn ignition on. Check continuity between ECM harness connector terminal No. 35 (Green/Orange wire) and ground. Move shift lever through gears. Continuity should exist ONLY in Park and Neutral. If continuity is not as specified, go to next step. If continuity is as specified, system is functioning properly.
2. Turn ignition off. Disconnect inhibitor relay. Relay is located in relay box next to battery. Place shift lever in Neutral or Park. Turn ignition on. Measure voltage between inhibitor relay connector terminal No. 1 and ground. (Scheme 54) Battery voltage should be present. If battery voltage is present, go to step 5). If battery voltage is not present, go to next step.
3. Turn ignition off. Disconnect and inspect inhibitor switch 8-pin harness connector for pushed-out, bent, damaged or corroded terminals. Repair connector as necessary. Connector is located on side of transaxle. Turn ignition on. Measure voltage between inhibitor switch 8-pin harness connector terminal "D" and ground. For terminal identification (Scheme 54) Battery voltage should be present. If battery voltage is present, go to next step. If battery voltage is not present, check harness and connectors for open. Also check 10-amp fuse. Repair as necessary.
4. Turn ignition off. Check continuity between inhibitor relay connector No. 1 and inhibitor switch 8-pin harness connector terminal "F". Check continuity between inhibitor relay connector No. 1 and inhibitor switch 8-pin harness connector terminal "H". For terminal identification (Scheme 54) Continuity should exist in both checks. If continuity does not exist, check harness and connectors for open. Repair as necessary. If continuity exists, check inhibitor switch. See INHIBITOR SWITCH TEST (ALTIMA, NX 2.0L, SENTRA 2.0L, QUEST & 240SX).
5. Turn ignition off. Check continuity between inhibitor relay connector No. 2 and ground. Check continuity between inhibitor relay connector No. 6 and ground. For terminal identification (Scheme 54) Continuity should exist in all checks. If continuity does not exist in any check, repair open in harness or connectors. If continuity exists in all checks, go to next step.
6. Check continuity between ECM harness connector terminal No. 35 (Green/Orange wire) and inhibitor relay connector No. 7. For terminal identification (Scheme 54) Continuity should exist. If continuity does not exist, repair open in harness or connectors. If continuity exists, check inhibitor relay. See «RELAYS»(ref-17400-S12256886262000122900000) under RELAYS & SOLENOIDS.

Scheme 54

INHIBITOR SWITCH SYSTEM TEST (PICKUP)

1. Turn ignition off. Disconnect and inspect ECM harness connector for pushed-out, bent, damaged or corroded terminals. Repair connector as necessary. Turn ignition on. Check continuity between ECM harness connector terminal No. 35 (Blue/Black wire) and ground. Move shift lever through gears. Continuity should exist ONLY in Park and Neutral. If continuity is not as specified, go to next step. If continuity is as specified, system is functioning properly.
2. Turn ignition off. Disconnect inhibitor relay. Relay is located on left fender panel near activated carbon canister. Place shift lever in Neutral or Park. Turn ignition on. Measure voltage between inhibitor relay connector terminal No. 2 and ground. For terminal identification (Scheme 55) Battery voltage should be present. If battery voltage is present, go to step 5). If battery voltage is not present, go to next step.
3. Turn ignition off. Disconnect and inspect inhibitor switch 2-pin harness connector for pushed-out, bent, damaged or corroded terminals. Repair connector as necessary. Connector is located on side of transmission. Turn ignition on. Measure voltage between inhibitor switch 2-pin harness connector White/Black wire and ground. Battery voltage should be present. If battery voltage is present, go to next step. If battery voltage is not present, check harness and connectors for open. Also check 10-amp fuse. Repair as necessary.
4. Turn ignition off. Check continuity between inhibitor relay connector No. 2 and inhibitor switch 2-pin harness connector Yellow wire. Continuity should exist. If continuity does not exist, check harness and connectors for open. Repair as necessary. If continuity exists, check inhibitor switch. See INHIBITOR SWITCH TEST (MAXIMA VE30DE, PICKUP & 300ZX).
5. Turn ignition off. Check continuity between inhibitor relay connector No. 1 and ground. Check continuity between inhibitor relay connector No. 5 and ground. For terminal identification (Scheme 55) Continuity should exist in all checks. If continuity does not exist in any check, repair open in harness or connectors. If continuity exists in all checks, go to next step.
6. Check continuity between ECM harness connector terminal No. 35 (Blue/Black wire) and inhibitor relay connector No. 3. For terminal identification (Scheme 55) Continuity should exist. If continuity does not exist, repair open in harness or connectors. If continuity exists, check inhibitor relay. See «RELAYS»(ref-17400-S12256886262000122900000) under RELAYS & SOLENOIDS.

Scheme 55

INHIBITOR SWITCH SYSTEM TEST (240SX)

1. Ensure inhibitor switch functions properly. See INHIBITOR SWITCH TEST (ALTIMA, NX 2.0L, SENTRA 2.0L, QUEST & 240SX). Ensure ignition is off. Disconnect and inspect ECM harness connector for pushed-out, bent, damaged or corroded terminals. Repair connector as necessary. Turn ignition on. Check continuity between ECM harness connector terminal No. 35 (Green/Orange wire) and ground. Move shift lever through gears. Continuity should exist ONLY in Park and Neutral. If continuity is not as specified, go to next step. If continuity is as specified, system is functioning properly.
2. Turn ignition off. Disconnect and inspect A/T control harness connector for pushed-out, bent, damaged or corroded terminals. Repair connector as necessary. Check continuity between ECM harness connector terminal No. 35 (Green/Orange wire) and A/T control unit harness connector terminal No. 13 (Green/Orange wire). Continuity should exist. If continuity does not exist, repair open in Green/Orange wire. If continuity does not exist, recheck ECM and A/T control unit harness connectors and repair as necessary.

INHIBITOR SWITCH SYSTEM TEST (300ZX)

1. Turn ignition on. Check voltage between ECM harness connector terminal No. 44 (Yellow/Blue wire) and ground. Move shift lever through gears. Zero volts should be present in Neutral and Park positions, and 8-9 volts should be present in all other positions. If voltage is not as specified, go to next step. If voltage is as specified, system is functioning properly.
2. Turn ignition off. Disconnect and inspect ECM harness connector for pushed-out, bent, damaged or corroded terminals. Repair connector as necessary. Disconnect and inspect A/T control unit harness connector for pushed-out, bent, damaged or corroded terminals. Repair connector as necessary.
3. Check continuity of Yellow/Blue wire between ECM harness connector terminal No. 44 and A/T control unit harness connector terminal No. 13. Continuity should exist. If continuity exists, check inhibitor switch. See INHIBITOR SWITCH TEST (MAXIMA VE30DE, PICKUP & 300ZX). If continuity does not exist, repair open in Yellow/Blue wire or connectors.

NEUTRAL POSITION SWITCH SYSTEM TEST (ALTIMA)

1. Turn ignition off. Disconnect and inspect ECM harness connector for pushed-out, bent, damaged or corroded terminals. Repair connector as necessary. Check continuity between ECM harness connector terminal No. 35 (Green/Orange wire) and ground. Move shift lever through gears. Continuity should exist ONLY in Neutral. If continuity is not as specified, go to next step. If continuity is as specified, system is functioning properly.
2. Turn ignition off. Disconnect and inspect Neutral position switch 4-pin harness connector for pushed-out, bent, damaged or corroded terminals. Connector is located on top of transaxle. Repair connector as necessary. Check continuity between Black wire of Neutral position switch 4-pin harness connector and ground. Continuity should exist. If continuity exists, go to next step. If continuity does not exist, repair open in Black wire or connectors.
3. Check continuity between ECM harness connector terminal No. 35 (Green/Orange wire) and Green/Orange wire of Neutral position switch 4-pin harness connector. Continuity should exist. If continuity exists, check Neutral position switch. See NEUTRAL POSITION SWITCH TEST (ALTIMA). If continuity does not exist, check harness and connectors for open. Repair as necessary.

NEUTRAL POSITION SWITCH TEST (ALTIMA)

Disconnect Neutral position switch 4-pin harness connector located on top of transaxle. Check continuity between Green/Orange wire and Black wire of Neutral position switch 4-pin connector. Continuity should exist with transaxle in Neutral. Continuity should not exist in any other position. If Neutral position switch does not function as described, replace switch.

NEUTRAL POSITION SWITCH SYSTEM TEST (MAXIMA VE30DE)

1. Turn ignition off. Disconnect and inspect ECM harness connector for pushed-out, bent, damaged or corroded terminals. Repair connector as necessary. Check continuity between ECM harness connector terminal No. 44 (Brown wire) and ground. Move shift lever through gears. Continuity should exist ONLY in Neutral. If continuity is not as specified, go to next step. If continuity is as specified, system is functioning properly.
2. Turn ignition off. Disconnect and inspect Neutral position switch 4-pin harness connector for pushed-out, bent, damaged or corroded terminals. Connector is located on top of transaxle. Repair connector as necessary. Check continuity between Black wire of Neutral position switch 4-pin harness connector and ground. Continuity should exist. If continuity exists, go to next step. If continuity does not exist, repair open in Black wire or connectors.
3. Check continuity between ECM harness connector terminal No. 44 (Brown wire) and Brown wire of Neutral position switch 4-pin harness connector. Continuity should exist. If continuity exists, check Neutral position switch. See NEUTRAL POSITION SWITCH TEST (MAXIMA VE30DE). If continuity does not exist, check harness and connectors for open. Repair as necessary.

NEUTRAL POSITION SIGNAL (A/T CONTROL UNIT) TEST (MAXIMA VE30DE & QUEST)

1. Turn ignition off. Disconnect and inspect ECM harness connector for pushed-out, bent, damaged or corroded terminals. Repair connector as necessary. On Maxima VE30DE, check continuity between ECM harness connector terminal No. 44 (Brown wire) and ground. On Quest, check continuity between ECM harness connector terminal No. 35 (Green/Black wire) and ground. On all models, move shift lever through gears. Continuity should exist ONLY in Neutral and Park. If continuity is not as specified, go to next step. If continuity is as specified, system is functioning properly.
2. Disconnect and inspect A/T control unit harness connector for pushed-out, bent, damaged or corroded terminals. Repair connector as necessary. On Maxima VE30DE, check continuity of Brown wire between ECM harness connector terminal No. 44 and A/T control unit harness connector terminal No. 44. On Quest, check continuity of Green/Black wire between ECM harness connector terminal No. 35 and A/T control unit harness connector terminal No. 13. On all models, continuity should exist.
3. If continuity exists, check A/T control unit. See appropriate TRANSMISSION SERVICE & REPAIR article. Also check inhibitor switch. On Maxima VE30DE, see INHIBITOR SWITCH TEST (MAXIMA VE30DE, PICKUP & 300ZX). On Quest, see INHIBITOR SWITCH TEST (ALTIMA, NX 2.0L, SENTRA 2.0L, QUEST & 240SX). On all models, if continuity does not exist, check harness and connectors for open. Repair as necessary.

NEUTRAL POSITION SWITCH TEST (MAXIMA VE30DE)

Disconnect Neutral position switch 4-pin harness connector located on top of transaxle. Check continuity between Brown wire and Black wire of Neutral position switch 4-pin connector. Continuity should exist with transaxle in Neutral. Continuity should not exist in any other position. If Neutral position switch does not function as described, replace switch.

NEUTRAL POSITION SWITCH SYSTEM TEST (NX & SENTRA)

1. Turn ignition off. Disconnect and inspect ECM harness connector for pushed-out, bent, damaged or corroded terminals. Repair connector as necessary. Check continuity between ECM harness connector terminal No. 35 (Green/Orange wire) and ground. Move shift lever through gears. Continuity should exist ONLY in Neutral. If continuity is not as specified, go to next step. If continuity is as specified, system is functioning properly.
2. Turn ignition off. Disconnect and inspect Neutral position switch 2-pin harness connector for pushed-out, bent, damaged or corroded terminals. Connector is located on top of transaxle. Repair connector as necessary. Check continuity between Black wire of Neutral position switch 2-pin harness connector and ground. Continuity should exist. If continuity exists, go to next step. If continuity does not exist, repair open in Black wire or connectors.
3. Check continuity between ECM harness connector terminal No. 35 (Green/Orange wire) and Green/Orange wire of Neutral position switch 2-pin harness connector. Continuity should exist. If continuity exists, check Neutral position switch. See NEUTRAL POSITION SWITCH TEST (NX & SENTRA). If continuity does not exist, check harness and connectors for open. Repair as necessary.

NEUTRAL POSITION SWITCH TEST (NX & SENTRA)

Disconnect Neutral position switch 2-pin harness connector located on top of transaxle. Check continuity between Neutral position switch 2-pin connector terminals. Continuity should exist with transaxle in Neutral. Continuity should not exist in any other position. If Neutral position switch does not function as described, replace switch.

NEUTRAL POSITION SWITCH SYSTEM TEST (PICKUP & 240SX)

1. Turn ignition off. Disconnect and inspect ECM harness connector for pushed-out, bent, damaged or corroded terminals. Repair connector as necessary. On Pickup, check continuity between ECM harness connector terminal No. 35 (Blue/Black wire) and ground. On 240SX, check continuity between ECM harness connector terminal No. 35 (Green/Orange wire) and ground. On all models, move shift lever through gears. Continuity should exist ONLY in Neutral. If continuity is not as specified, go to next step. If continuity is as specified, system is functioning properly.
2. Disconnect and inspect Neutral position switch 2-pin harness connector for pushed-out, bent, damaged or corroded terminals. Connector is located on transmission tailshaft housing. Repair connector as necessary. Check continuity between Black wire of Neutral position switch 2-pin harness connector and ground. Continuity should exist. If continuity exists, go to next step. If continuity does not exist, repair open in Black wire or connectors.
3. On Pickup, check continuity between ECM harness connector terminal No. 35 (Blue/Black wire) and Blue/Black wire of Neutral position switch 2-pin harness connector. On 240SX, check continuity between ECM harness connector terminal No. 35 (Green/Orange wire) and Green/Orange wire of Neutral position switch 2-pin harness connector. On all models, continuity should exist. If continuity exists, check Neutral position switch. See NEUTRAL POSITION SWITCH TEST (PICKUP, 240SX & 300ZX). If continuity does not exist, check harness and connectors for open. Repair as necessary.

NEUTRAL POSITION SWITCH TEST (PICKUP, 240SX & 300ZX)

Disconnect Neutral position switch 2-pin harness connector located on top of transmission tailshaft housing. Check continuity between Neutral position switch 2-pin connector terminals. Continuity should exist with transmission in Neutral. Continuity should not exist in any other position. If Neutral position switch does not function as described, replace switch.

NEUTRAL POSITION SWITCH SYSTEM TEST (300ZX)

1. Turn ignition on. Check voltage between ECM harness connector terminal No. 44 (Yellow/Blue wire) and ground. Move shift lever through gears. Zero volts should be present in Neutral and 8-9 volts should be present in all other positions. If voltage is not as specified, go to next step. If voltage is as specified, system is functioning properly.
2. Turn ignition off. Disconnect and inspect ECM harness connector for pushed-out, bent, damaged or corroded terminals. Repair connector as necessary. Disconnect and inspect Neutral position harness connector for pushed-out, bent, damaged or corroded terminals. Repair connector as necessary.
3. Check continuity of Yellow/Blue wire between ECM harness connector terminal No. 44 and Neutral position switch harness connector. Continuity should exist. If continuity exists, check Neutral position switch. See NEUTRAL POSITION SWITCH TEST (PICKUP, 240SX & 300ZX). If continuity does not exist, repair open in Yellow/Blue wire or connectors.

POWER STEERING PRESSURE SWITCH SYSTEM TEST (ALTIMA, NX, SENTRA, PICKUP 2.4L & 240SX)

1. Start engine and bring to operating temperature. Measure voltage between ECM harness connector terminal No. 43 and ground. For wire color, see ECM CONNECTOR TERMINAL NO. 43 WIRE COLOR table. Turn steering wheel quickly; approximately zero volts should be present. When steering wheel is not being turned, 7-9 volts should be present. If voltage is not as specified, go to next step. If voltage is as specified, system is functioning properly.
2. Turn ignition off. Disconnect and inspect power steering pressure switch harness connector for pushed-out, bent, damaged or corroded terminals. Repair connector as necessary. Check continuity between power steering pressure switch harness connector Black wire and ground. Continuity should exist. If continuity exists, go to next step. If continuity does not exist, repair open in Black wire or connectors.
3. Disconnect and inspect ECM harness connector for pushed-out, bent, damaged or corroded terminals. Repair connector as necessary. Check continuity between ECM harness connector terminal No. 43 and appropriate wire at power steering pressure switch harness connector. Continuity should exist. If continuity exists, check power steering pressure switch. See POWER STEERING PRESSURE SWITCH TEST. If continuity does not exist, repair open in appropriate wire or connectors.

ECM CONNECTOR TERMINAL NO. 43 WIRE COLOR

POWER STEERING PRESSURE SWITCH SYSTEM TEST (MAXIMA & 300ZX)

1. Start engine and bring to operating temperature. Measure voltage between ECM harness connector terminal No. 34 (Green wire) and ground. Turn steering wheel quickly; approximately zero volts should be present. When steering wheel is not being turned, 4-6 volts (Maxima) or 8-9 volts (300ZX) should be present. If voltage is not as specified, go to next step. If voltage is as specified, system is functioning properly.
2. Turn ignition off. Disconnect and inspect power steering pressure switch harness connector for pushed-out, bent, damaged or corroded terminals. Repair connector as necessary. Check continuity between power steering pressure switch harness connector Black wire and ground. Continuity should exist. If continuity exists, go to next step. If continuity does not exist, repair open in Black wire or connectors.
3. Disconnect and inspect ECM harness connector for pushed-out, bent, damaged or corroded terminals. Repair connector as necessary. Check continuity between ECM harness connector terminal No. 34 (Green wire) and power steering pressure switch harness connector Green wire. Continuity should exist. If continuity exists, check power steering pressure switch. See POWER STEERING PRESSURE SWITCH TEST. If continuity does not exist, repair open in Green wire or connectors.

POWER STEERING PRESSURE SWITCH SYSTEM TEST (PATHFINDER, PICKUP 3.0L & QUEST)

1. Start engine and bring to operating temperature. Measure voltage between ECM harness connector terminal No. 12 and ground. For wire color, see ECM CONNECTOR TERMINAL NO. 12 WIRE COLOR table. Turn steering wheel quickly; 0-2 volts should be present. When steering wheel is not being turned, 4.8-4.9 volts should be present. If voltage is not as specified, go to next step. If voltage is as specified, system is functioning properly.
2. Turn ignition off. Disconnect and inspect power steering pressure switch harness connector for pushed-out, bent, damaged or corroded terminals. Repair connector as necessary. Check continuity between power steering pressure switch harness connector Black wire and ground. Continuity should exist. If continuity exists, go to next step. If continuity does not exist, repair open in Black wire or connectors.
3. Disconnect and inspect ECM harness connector for pushed-out, bent, damaged or corroded terminals. Repair connector as necessary. Check continuity between ECM harness connector terminal No. 12 and appropriate wire of power steering pressure switch harness connector. Continuity should exist. If continuity exists, check power steering pressure switch. See POWER STEERING PRESSURE SWITCH TEST. If continuity does not exist, repair open in appropriate wire or connectors.

ECM CONNECTOR TERMINAL NO. 12 WIRE COLOR

POWER STEERING PRESSURE SWITCH TEST

Disconnect switch connector. Switch is attached to power steering high pressure hose. Check resistance between switch connector terminals. On 300ZX, replace switch if resistance is not 2-3 ohms. On all others, start engine. Replace switch if continuity is not as specified in POWER STEERING PRESSURE SWITCH (EXCEPT 300ZX) table.

POWER STEERING PRESSURE SWITCH (EXCEPT 300ZX)

Note. On Maxima, Pathfinder, Pickup 3.0L and 300ZX, perform Throttle Position Sensor (TPS) test at connector farthest from TPS, not at connector which terminates directly at TPS.

Valve Timing Control (VTC) Solenoid System Test (Maxima VE30DE)

1. Raise and support front of vehicle. Start engine. Place gear selector in any gear except Neutral (M/T) or Neutral or Park(A/T). Measure voltage between ground and ECM harness connector terminal No. 113 (Yellow/Green wire). see scheme 1and see scheme 2. ECM is located under center of instrument panel (connector is on driver's side). At idle, battery voltage should be present. Quickly depress and release accelerator pedal. Voltage should be 0.2-0.5 volt. If voltage is not as specified, go to step 3). If voltage is as specified, go to next step.
2. Stop engine. Connect jumper wire between ground and ECM harness connector terminal No. 113 (Yellow/Green wire). Start engine. Improper idle condition should occur. If improper idle condition occurs, system is functioning properly. If improper idle condition does not occur, check VTC solenoid. See VALVE TIMING CONTROL (VTC) SOLENOID TEST.
3. Disconnect both VTC solenoid harness connectors. VTC solenoids are located on flywheel end of each cylinder head. Turn ignition on. Measure voltage between ground and each VTC solenoid harness connector Red/Black wire. Battery voltage should be present. If battery voltage is present, go to next step. If battery voltage is not present, check 10-amp fuse. Check harness continuity between VTC solenoids and fuse. Repair or replace as necessary.
4. Turn ignition off. Disconnect ECM harness connector. Check continuity between ECM harness connector terminal No. 113 (Yellow/Green wire) and each VTC harness connector Yellow/Green wire. Continuity should exist. If continuity exists, check VTC solenoid. See VALVE TIMING CONTROL (VTC) SOLENOID TEST. If solenoid is okay, check ECM and harness terminals for damage or corrosion. Repair as necessary. If continuity does not exist, repair open in Yellow/Green wire or connectors.

Valve Timing Control (VTC) Solenoid System Test (NX 1.6L & Sentra 1.6L)

1. Connect jumper wire between ground and ECM harness connector terminal No. 12 (Green/White wire). see scheme 1and see scheme 2. ECM is located under center of instrument panel. Start engine. Improper idle condition should occur. If improper idle condition occurs, system is functioning properly. If improper idle condition does not occur, go to next step.
2. Raise and support front of vehicle. Start engine. Place gear selector in any gear except Neutral (M/T) or Neutral or Park (A/T). Measure voltage between ground and ECM harness connector terminal No. 12 (Green/White wire). At idle, battery voltage should be present. Quickly depress and release accelerator pedal. Approximately zero volts should be present. If voltage is not as specified, check VTC solenoid. See VALVE TIMING CONTROL (VTC) SOLENOID TEST. If voltage is as specified, go to next step.
3. Turn ignition off. Disconnect VTC solenoid harness connector. VTC solenoid is located on cylinder head, right of intake manifold. Turn ignition on. Measure voltage between ground and VTC solenoid harness connector White/Green wire. Battery voltage should be present. If battery voltage is present, go to next step. If battery voltage is not present, check 10-amp fuse. Check harness continuity between VTC solenoid and fuse. Repair or replace as necessary.
4. Turn ignition off. Disconnect ECM harness connector. Check continuity between ECM harness connector terminal No. 12 (Green/White wire) and VTC harness connector Green/White wire. Continuity should exist. If continuity exists, check VTC solenoid. See VALVE TIMING CONTROL (VTC) SOLENOID TEST. If solenoid is okay, check ECM and harness terminals for damage or corrosion. Repair as necessary. If continuity does not exist, repair open in Green/White wire or connectors.

Valve Timing Control (VTC) Solenoid System Test (300ZX)

1. Turn ignition on. Measure voltage between ground and each VTC solenoid harness connector Black/Red wire. VTC solenoids are located on flywheel end of each cylinder head. Battery voltage should be present. If battery voltage is present, go to step 3). If battery voltage is not present, go to next step.
2. Check Green fusible link, located in fusible link box near battery. Check 10-amp fuse in relay box, located at left front corner of engine compartment. Check harness continuity between VTC solenoids and ignition switch. Check harness continuity between ignition switch and battery positive terminal. If continuity does not exist, repair circuit as necessary.
3. Turn ignition off. Disconnect ECM harness connector. Disconnect VTC solenoid harness connectors. Check continuity between ECM harness connector terminal No. 113 (Green/Black wire) and VTC harness connector Green/Black wire. see scheme 1and see scheme 2. Continuity should exist. If continuity exists, check VTC solenoid. See VALVE TIMING CONTROL (VTC) SOLENOID TEST. If continuity does not exist, repair or replace harness or connectors as necessary.

Valve Timing Control (VTC) Solenoid Test

VTC solenoids are located on rear corner of each cylinder head. To test solenoid, apply battery voltage across solenoid terminals. Replace solenoid if it does not operate.

Wastegate Valve Control Solenoid System Test (300ZX Turbo)

1. Turn ignition on. Measure voltage between ground and each wastegate valve control solenoid harness connector Black/Red wire. Solenoids are located below right and left intake manifold collector. Battery voltage should be present. If battery voltage is present, go to step 3). If battery voltage is not present, go to next step.
2. Turn ignition off. Check Green fusible link, located in fusible link box near battery. Check 10-amp fuse in relay box, located at left front corner of engine compartment. Check harness continuity between wastegate valve control solenoids and ignition switch. Check harness continuity between ignition switch and battery positive terminal. If continuity does not exist, repair circuit as necessary.
3. Turn ignition off. Check continuity between ECM harness connector terminal No. 25 (Sky Blue wire) and each wastegate valve control solenoid harness connector Sky Blue wire. see scheme 1and see scheme 2. Continuity should exist. If continuity exists, check solenoid. See WASTEGATE VALVE CONTROL SOLENOID TEST (300ZX TURBO). If continuity does not exist, repair or replace harness or connectors as necessary.

Wastegate Valve Control Solenoid Test (300ZX Turbo)

To test solenoid, apply vacuum to either port on valve. If vacuum does not hold, replace solenoid. If vacuum holds, apply battery voltage across solenoid terminals. If vacuum holds, replace solenoid.

Pressure Regulator Vacuum Relief (PRVR) Control Solenoid System Test (300ZX)

1. Turn ignition on. Measure voltage between ground and PRVR control solenoid harness connector Black/Red wire. PRVR solenoid is located above front branch of left exhaust manifold (non-turbo) or near brake master cylinder (turbo). Battery voltage should be present. If battery voltage is present, go to step 3). If battery voltage is not present, go to next step.
2. Turn ignition off. Check Green fusible link, located in fusible link box near battery. Check 10-amp fuse in relay box, located at left front corner of engine compartment. Check harness continuity between PRVR control solenoid and ignition switch. Check harness continuity between ignition switch and battery positive terminal. If continuity does not exist, repair circuit as necessary.
3. Turn ignition off. Check continuity between ECM harness connector terminal No. 111 (Yellow wire) and PRVR control solenoid harness connector Yellow wire. see scheme 1and see scheme 2. Continuity should exist. If continuity exists, check solenoid. See PRESSURE REGULATOR VACUUM RELIEF (PRVR) CONTROL SOLENOID TEST (300ZX). If continuity does not exist, repair or replace harness or connectors as necessary.

Pressure Regulator Vacuum Relief (PRVR) Control Solenoid Test (300ZX)

1. To test solenoid, disconnect vacuum lines and electrical connector from solenoid. Remove solenoid. Apply vacuum to port "B" of solenoid. (Scheme 65) Vacuum should now be available at port "C", but not at port "A".
2. Apply battery voltage across solenoid connector terminals. Vacuum should now be available at port "A", but not at port "C". Replace solenoid if it does not operate as specified.

Fuel Pump System Test (Altima)

1. Turn ignition on. With fingers, pinch fuel feed hose at fuel filter. Fuel pressure pulsation should be felt for 5 seconds after ignition is turned on. If pulsation is not felt, go to next step. If pulsation is felt, system is functioning properly.
2. Turn ignition off. Disconnect fuel pump relay. Fuel pump relay is located in relay box next to battery. Turn ignition on. Measure voltage between ground and fuel pump relay harness connector terminals No. 1 (Blue/Black wire) and No. 3 (Blue/Black wire). (Scheme 56) Battery voltage should be present. If battery voltage is present, go to next step. If battery voltage is not present, check 15-amp fuse in main fuse box. Check harness continuity between fuse and fuel pump relay. Repair or replace as necessary.
3. Turn ignition off. Disconnect fuel pump harness connector, located under rear seat. Check continuity between ground and fuel pump harness connector Black wire. Check continuity between fuel pump relay harness connector terminal No. 5 (Black/Red wire) and fuel pump harness connector Black/Red wire. Continuity should exist in both checks. If continuity exists in both checks, go to next step. If continuity does not exist, repair appropriate harness or connectors.
4. Ensure ignition is off. Disconnect ECM harness connector. ECM is located under center of instrument panel (connector is on passenger's side). Check continuity between ECM harness connector terminal No. 104 (Black/Yellow wire) and fuel pump relay harness connector No. 2 (Black/Yellow wire). see scheme 1, see scheme 2 and (Scheme 56). Continuity should exist. If continuity exists, check fuel pump relay. See «RELAYS»(ref-17400-S12256886262000122900000) under RELAYS & SOLENOIDS. If relay is okay, check fuel pump. See FUEL PUMP TEST. If continuity does not exist, check harness between ECM and relay. Repair harness and connectors as necessary.

Scheme 56

Fuel Pump System Test (Maxima VG30E)

Fault in fuel pump circuit may set Code 22. To test system, see CODE 22 diagnostic procedures in TESTS W/CODES article.

Fuel Pump System Test (Maxima VE30DE)

1. Turn ignition on. Listen for fuel pump operating sound. Fuel pump should operate for 5 seconds after ignition is turned on. If operating sound is not heard, go to next step. If operating sound is heard, system is functioning properly.
2. Turn ignition off. Disconnect fuel pump relay. Fuel pump relay is located inside trunk trim, near striker. Turn ignition on. Measure voltage between ground and fuel pump relay harness connector terminals No. 2 (Blue wire) and No. 3 (Blue wire). (Scheme 57) Battery voltage should be present. If battery voltage is present, go to next step. If battery voltage is not present, check 10-amp fuse in main fuse box. Check harness continuity between fuse and fuel pump relay. Repair or replace as necessary.
3. Turn ignition off. Disconnect fuel pump harness connector, located under rear seat cushion. Check continuity between ground and fuel pump harness connector terminal "a" (Black wire). Check continuity between fuel pump relay harness connector terminal No. 5 (Red/Blue wire) and fuel pump harness connector terminal "c" (Red/Blue wire). (Scheme 57) Continuity should exist in both checks. If continuity exists in both checks, go to next step. If continuity does not exist in either check, repair appropriate harness or connectors.
4. Ensure ignition is off. Disconnect ECM harness connector. ECM is located under center of instrument panel (connector is on driver's side). Check continuity between ECM harness connector terminal No. 18 (Brown/Yellow wire) and fuel pump relay harness connector No. 1 (Blue/White wire). see scheme 1, see scheme 2 and (Scheme 57). Continuity should exist. If continuity exists, check fuel pump relay. See «RELAYS»(ref-17400-S12256886262000122900000) under RELAYS & SOLENOIDS. If relay is okay, check fuel pump. See FUEL PUMP TEST. If continuity does not exist, check harness between ECM and relay. Repair harness and connectors as necessary.

Scheme 57

Fuel Pump System Test (NX & Sentra)

1. Turn ignition on. With fingers, pinch fuel feed hose at fuel filter. Fuel pressure pulsation should be felt for 5 seconds after ignition is turned on. If pulsation is not felt, go to next step. If pulsation is felt, system is functioning properly.
2. Turn ignition off. Disconnect fuel pump relay. Fuel pump relay is located in relay box next to battery. Turn ignition on. Measure voltage between ground and fuel pump relay harness connector terminals No. 2 (Brown wire) and No. 3 (Brown wire). For connector identification (Scheme 56) Battery voltage should be present. If battery voltage is present, go to next step. If battery voltage is not present, check 15-amp fuse in main fuse box. Check harness continuity between fuse and fuel pump relay. Repair or replace as necessary.
3. Turn ignition off. Disconnect fuel pump harness connector, located under rear seat. Check continuity between ground and fuel pump harness connector Black wire. Check continuity between fuel pump relay harness connector terminal No. 5 (Black/Red wire) and fuel pump harness connector Black/Red wire. Continuity should exist in both checks. If continuity exists in both checks, go to next step. If continuity does not exist, repair appropriate harness or connectors.
4. Ensure ignition is off. Disconnect ECM harness connector. ECM is located under center of instrument panel. Check continuity between ECM harness connector terminal No. 104 (Black/Yellow wire) and fuel pump relay harness connector No. 1 (Black/Yellow wire). For terminal identification see scheme 1, see scheme 2 and (Scheme 56). Continuity should exist. If continuity exists, check fuel pump relay. See «RELAYS»(ref-17400-S12256886262000122900000) under RELAYS & SOLENOIDS. If relay is okay, check fuel pump. See FUEL PUMP TEST. If continuity does not exist, check harness between ECM and relay. Repair harness and connectors as necessary.

Fuel Pump System Test (Pathfinder & Pickup)

1. Turn ignition on. Listen for fuel pump operating sound. Fuel pump should operate for 5 seconds after ignition is turned on. If operating sound is not heard, go to next step. If operating sound is heard, system is functioning properly.
2. Turn ignition off. Disconnect fuel pump relay. Fuel pump relay is located in relay box on right front inner fender panel. Turn ignition on. Measure voltage between ground and fuel pump relay harness connector terminals No. 2 (Black/White wire) and No. 3 (Black/White wire). For connector identification (Scheme 56) Battery voltage should be present. If battery voltage is present, go to next step. If battery voltage is not present, check 10-amp fuse in main fuse box. Check harness continuity between fuse and fuel pump relay. Repair or replace as necessary.
3. Turn ignition off. Disconnect fuel pump harness connector, located under vehicle on right frame rail. Check continuity between ground and fuel pump harness connector Black wire. Check continuity between fuel pump relay harness connector terminal No. 5 (White/Blue wire) and fuel pump harness connector White/Blue wire. Continuity should exist in both checks. If continuity exists in both checks, go to next step. If continuity does not exist in either check, repair appropriate harness or connectors.
4. Ensure ignition is off. Disconnect ECM harness connector. ECM is located under passenger's seat. Check continuity between ECM harness connector terminal No. 104 (White/Red wire on Pickup 2.4L or Red/Blue wire on Pathfinder and Pickup 3.0L) and fuel pump relay harness connector No. 1 (White/Red wire on Pickup 2.4L or Red/Blue wire on Pathfinder and Pickup 3.0L). For terminal identification see scheme 1, see scheme 2 and (Scheme 56). Continuity should exist. If continuity exists, check fuel pump relay. See RELAYS under «RELAYS & SOLENOIDS»(ref-17400-S26910750242000122900000). If relay is okay, check fuel pump. See FUEL PUMP TEST. If continuity does not exist, check harness between ECM and relay. Repair harness and connectors as necessary.

Fuel Pump System Test (Quest)

1. If engine cranks but does not start, check inertia switch. Inertia switch is located behind driver's kick panel and is accessible through hole in kick panel. If gasoline smell is present, locate and repair cause of smell before resetting inertia switch.
2. Turn ignition on. With fingers, pinch fuel feed hose at fuel filter. Fuel pressure pulsation should be felt for 5 seconds after ignition is turned on. If pulsation is not felt, go to next step. If pulsation is felt, system is functioning properly.
3. Turn ignition off. Disconnect fuel pump relay. Fuel pump relay is located in relay box in front of battery. Turn ignition on. Measure voltage between ground and fuel pump relay harness connector terminals No. 1 (Black/Red wire) and No. 3 (Black/Red wire). For connector identification (Scheme 56) Battery voltage should be present. If battery voltage is present, go to next step. If battery voltage is not present, check 15-amp fuse in main fuse box. Check harness continuity between fuse and fuel pump relay. Repair or replace as necessary.
4. Turn ignition off. Disconnect fuel pump harness connector, located next to spare tire. Check continuity between ground and fuel pump harness connector Black/White wire. Check continuity between fuel pump relay harness connector terminal No. 5 (Light Green/Red wire) and fuel pump harness connector Light Green/Red wire. Continuity should exist in both checks. If continuity exists in both checks, go to next step. If continuity does not exist in either check, repair appropriate harness or connectors.
5. Ensure ignition is off. Disconnect ECM harness connector. ECM is located behind glove box. Check continuity between ECM harness connector terminal No. 104 (Blue/Red wire) and fuel pump relay harness connector terminal No. 2 (Blue/Red wire). For terminal identification see scheme 1, see scheme 2 and (Scheme 56). Continuity should exist. If continuity exists, check fuel pump relay. See «RELAYS»(ref-17400-S12256886262000122900000) under RELAYS & SOLENOIDS. If relay is okay, check fuel pump. See FUEL PUMP TEST. If continuity does not exist, check harness between ECM and relay. Repair harness and connectors as necessary.

Fuel Pump System Test (240SX)

1. Turn ignition on. Listen for fuel pump operating sound. Fuel pump should operate for 5 seconds after ignition is turned on. If operating sound is not heard, go to next step. If operating sound is heard, system is functioning properly.
2. Turn ignition off. Disconnect fuel pump relay. Fuel pump relay is located in fuse box next to battery. Turn ignition on. Measure voltage between ground and fuel pump relay harness connector terminals No. 1 (Black/White wire) and No. 5 (Black/White wire). For terminal identification (Scheme 57) Battery voltage should be present. If battery voltage is present, go to next step. If battery voltage is not present, check 10-amp fuse in main fuse box. Check harness continuity between fuse and fuel pump relay. Repair or replace as necessary.
3. Turn ignition off. Disconnect fuel pump harness connector, located under rear seat. Check continuity between ground and fuel pump harness connector terminal "a" (Black wire). Check continuity between fuel pump relay harness connector terminal No. 3 (Black/Yellow wire) and fuel pump harness connector terminal "c" (Black/Yellow wire). For terminal identification (Scheme 57) Continuity should exist in both checks. If continuity exists in both checks, go to next step. If continuity does not exist, repair appropriate harness or connectors.
4. Ensure ignition is off. Disconnect ECM harness connector. ECM is located behind passenger's kick panel. Check continuity between ECM harness connector terminal No. 104 (Black/Pink wire) and fuel pump relay harness connector No. 2 (Black/Pink wire). see scheme 1, see scheme 2 and (Scheme 57). Continuity should exist. If continuity exists, check fuel pump relay. See «RELAYS»(ref-17400-S12256886262000122900000) under RELAYS & SOLENOIDS. If relay is okay, check fuel pump. See FUEL PUMP TEST. If continuity does not exist, check harness between ECM and relay. Repair harness and connectors as necessary.

Fuel Pump System Test (300ZX)

1. With connector connected, measure voltage between ground and fuel pump harness connector terminal "a" (Orange wire). (Scheme 58) Connector is located under rear seat. Turn ignition on. Battery voltage should be present for one second after ignition is turned on. If voltage is as specified, go to step 3). If voltage is not as specified, go to next step.
2. Turn ignition off. Check Green fusible link located in fusible link holder next to battery. Check harness continuity between battery positive terminal and fuel pump relay (White/Black wire). Check harness continuity between fuel pump relay and fuel pump (Orange wire). Check harness continuity between fuel pump relay and ECM harness connector terminal No. 18 (Black/Pink wire). Continuity should exist in all checks. If continuity does not exist, repair appropriate harness or connector. If continuity exists, check fuel pump relay. See «RELAYS»(ref-17400-S12256886262000122900000) under RELAYS & SOLENOIDS.
3. Measure voltage between ground and fuel pump harness connector terminal "b". (Scheme 58) Start engine. Battery voltage should be present for 30 seconds after starting engine. After 30 seconds, voltage should be 3-6 volts with engine idling. If voltage is as specified, system is functioning properly. If voltage is not as specified, go to next step.
4. Check harness continuity between fuel pump and fuel pump control module (White wire). Fuel pump control module is located behind trim panel next to left rear seat. Check harness continuity between ECM harness connector terminal No. 104 (Black/Pink wire) and fuel pump control module. see scheme 1and see scheme 2. Continuity should exist in all checks. If continuity does not exist, repair appropriate harness or connector. If continuity exists, check fuel pump. See FUEL PUMP TEST.

Scheme 58

Fuel Pump Test

To test fuel pump, disconnect fuel pump connector, accessible through trunk (Maxima and 300ZX), under rear seat (Altima, NX and Sentra) or under vehicle body (Pathfinder, Pickup, Quest and 240SX). At fuel pump connector, check resistance between wire terminals specified in FUEL PUMP RESISTANCE TEST table. If resistance is not as specified, replace fuel pump.

FUEL PUMP RESISTANCE TEST

Fuel Injector System Test (Altima)

1. With engine running, measure voltage between ground and ECM harness connector terminals No. 101 (Brown wire), No. 103 (Brown/Yellow wire), No. 110 (Brown/White wire), and No. 112 (Brown wire). ECM is located under center of instrument panel. see scheme 1and see scheme 2. Battery voltage should be present. If battery voltage is not present, go to next step. If battery voltage is present, system is functioning properly.
2. Turn ignition off. Disconnect each injector harness connector. Measure voltage between ground and each injector harness connector White wire. Battery voltage should be present. If battery voltage is present, go to next step. If battery voltage is not present, check 75-amp fusible link and 10-amp fuse located in engine compartment fuse box. If 75-amp fusible link and 10-amp fuse are okay, repair or replace harness or connectors.
3. Ensure ignition is off. Disconnect ECM harness connector. Measure voltage between ground and ECM harness connector terminal No. 109 (White wire). Battery voltage should be present. If battery voltage is present, go to next step. If battery voltage is not present, check 25-amp fuse, located in fuse box in engine compartment. If 25-amp fuse is okay, repair or replace harness or connectors.
4. Check continuity between ECM harness connector terminals No. 101 (Brown wire), No. 103 (Brown/Yellow wire), No. 110 (Brown/White wire), and No. 112 (Brown wire) and corresponding injector harness connector wire color. Continuity should exist. If continuity exists, check injector. See FUEL INJECTOR TEST. If injector is okay, check ECM pin terminals and ECM harness connector terminals for damage or corrosion. Repair or replace as necessary. If continuity does not exist, repair or replace harness or connectors.

Fuel Injector System Test (Maxima)

Fault in the fuel injector circuit may set Code 51. To test system, see CODE 51 diagnostic procedures in TESTS W/CODES article.

Fuel Injector System Test (NX & Sentra)

1. With engine running, listen for clicking sound at each injector. If clicking sound is present at each injector, system is functioning properly. If clicking sound is not present, go to next step.
2. Turn ignition off. Disconnect each injector harness connector. Measure voltage between ground and each injector harness connector White wire. Battery voltage should be present. If battery voltage is present, go to next step. If battery voltage is not present, check 25-amp fusible link located in fuse, fusible link and relay box next to battery. If 25-amp fusible link is okay, repair or replace harness or connectors.
3. Ensure ignition is off. Disconnect ECM harness connector. Check continuity between ECM harness connector terminals No. 101 (White/Black wire), No. 103 (Green/Black wire), No. 110 (Yellow/Black wire), and No. 112 (Blue/Black wire) and corresponding injector harness connector wire color. ECM is located under center of instrument panel. see scheme 1and see scheme 2. Continuity should exist. If continuity exists, check injector. See FUEL INJECTOR TEST. If injector is okay, check ECM pin terminals and ECM harness connector terminals for damage or corrosion. Repair or replace as necessary. If continuity does not exist, repair or replace harness or connectors.

Fuel Injector System Test (Pathfinder & Pickup 3.0L CA)

Fault in the fuel injector circuit may set Code 51. To test system, see CODE 51 diagnostic procedures in TESTS W/CODES article.

Fuel Injector System Test (Pathfinder & Pickup 3.0L Fed.)

1. With engine running, measure voltage between ground and ECM harness connector terminals No. 101 (White wire), No. 103 (White/Red wire), No. 105 (White/Green wire), No. 110 (Yellow wire), No. 112 (White/Blue wire) and No. 114 (White/Black wire). ECM is located under passenger seat. see scheme 1and see scheme 2. Battery voltage should be present. If battery voltage is not present, go to next step. If battery voltage is present, system is functioning properly.
2. Turn ignition off. Disconnect each injector harness connector. Disconnect ECM harness connector. Measure voltage between ground and each injector harness connector White/Red wire. Measure voltage between ground and ECM harness connector terminal No. 46 (White/Red wire). Battery voltage should be present. If battery voltage is present, go to next step. If battery voltage is not present, check Brown fusible link connected to positive battery post. If fusible is okay, repair or replace harness or connectors.
3. Check continuity between ECM harness connector terminals No. 101 (White wire), No. 103 (White/Red wire), No. 105 (White/Green wire), No. 110 (Yellow wire), No. 112 (White/Blue wire) and No. 114 (White/Black wire) and corresponding injector harness connector wire color. Continuity should exist. If continuity exists, check injector. See FUEL INJECTOR TEST. If injector is okay, check ECM pin terminals and ECM harness connector terminals for damage or corrosion. Repair or replace as necessary. If continuity does not exist, repair or replace harness or connectors.

Fuel Injector System Test (Pickup 2.4L)

1. With engine running, measure voltage between ground and ECM harness connector terminals No. 101 (White/Black wire), No. 103 (White/Red wire), No. 110 (White/Blue wire), and No. 112 (White/Green wire). ECM is located under passenger seat. see scheme 1and see scheme 2. Battery voltage should be present. If battery voltage is not present, go to next step. If battery voltage is present, system is functioning properly.
2. Turn ignition off. Disconnect each injector harness connector. Disconnect ECM harness connector. Measure voltage between ground and each injector harness connector White wire. Measure voltage between ground and ECM harness connector terminal No. 46 (White wire). Battery voltage should be present. If battery voltage is present, go to next step. If battery voltage is not present, check Brown fusible link connected to positive battery post. If fusible is okay, repair or replace harness or connectors.
3. Check continuity between ECM harness connector terminals No. 101 (White/Black wire), No. 103 (White/Red wire), No. 110 (White/Blue wire), and No. 112 (White/Green wire) and corresponding injector harness connector wire color. Continuity should exist. If continuity exists, check injector. See FUEL INJECTOR TEST. If injector is okay, check ECM pin terminals and ECM harness connector terminals for damage or corrosion. Repair or replace as necessary. If continuity does not exist, repair or replace harness or connectors.

Fuel Injector System Test (Quest - California)

Fault in the fuel injector circuit may set Code 51. To test system, see CODE 51 diagnostic procedures in TESTS W/CODES article.

Fuel Injector System Test (Quest Non-California)

1. With engine running, measure voltage between ground and ECM harness connector terminals No. 101 (Green/Orange wire), No. 103 (Green/Red wire), No. 105 (Yellow/Green wire), No. 110 (Green wire), No. 112 (Yellow/Purple wire) and No. 114 (Gray/Blue wire). ECM is located behind glove box. see scheme 1and see scheme 2. Battery voltage should be present. If battery voltage is not present, go to next step. If battery voltage is present, system is functioning properly.
2. Turn ignition off. Disconnect each injector harness connector. Disconnect ECM harness connector. Measure voltage between ground and each injector harness connector Yellow wire. Measure voltage between ground and ECM harness connector terminal No. 46 (Yellow wire). Battery voltage should be present. If battery voltage is present, go to next step. If battery voltage is not present, check 25-amp fusible link located in fusible link box next to battery. If fusible is okay, repair or replace harness or connectors.
3. Check continuity between ECM harness connector terminals No. 101 (Green/Orange wire), No. 103 (Green/Red wire), No. 105 (Yellow/Green wire), No. 110 (Green wire), No. 112 (Yellow/Purple wire) and No. 114 (Gray/Blue wire) and corresponding injector harness connector wire color. Continuity should exist. If continuity exists, check injector. See FUEL INJECTOR TEST. If injector is okay, check ECM pin terminals and ECM harness connector terminals for damage or corrosion. Repair or replace as necessary. If continuity does not exist, repair or replace harness or connectors.

Fuel Injector System Test (240SX)

1. With engine running, measure voltage between ground and ECM harness connector terminals No. 101 (White/Black wire), No. 103 (Green/Black wire), No. 110 (Yellow/Black wire), and No. 112 (Blue/Black wire). ECM is located behind passenger side kick panel. see scheme 1and see scheme 2. Battery voltage should be present. If battery voltage is not present, go to next step. If battery voltage is present, system is functioning properly.
2. Turn ignition off. Disconnect each injector harness connector. Disconnect ECM harness connector. Measure voltage between ground and each injector harness connector Red wire. Measure voltage between ground and ECM harness connector terminal No. 109 (Red wire). Battery voltage should be present. If battery voltage is present, go to next step. If battery voltage is not present, check Brown fusible link located in fuse and fusible link box behind battery. If fusible is okay, repair or replace harness or connectors.
3. Check continuity between ECM harness connector terminals No. 101 (White/Black wire), No. 103 (Green/Black wire), No. 110 (Yellow/Black wire), and No. 112 (Blue/Black wire) and corresponding injector harness connector wire color. Continuity should exist. If continuity exists, check injector. See FUEL INJECTOR TEST. If injector is okay, check ECM pin terminals and ECM harness connector terminals for damage or corrosion. Repair or replace as necessary. If continuity does not exist, repair or replace harness or connectors.

Fuel Injector System Test (300ZX - California)

Fault in the fuel injector circuit may set Code 51. To test system, see CODE 51 diagnostic procedures in TESTS W/CODES article.

Fuel Injector System Test (300ZX - Non-California)

Fault in the fuel injector circuit will not set Code 51. To test system, see CODE 51 diagnostic procedures in TESTS W/CODES article.

Fuel Injector Test

Check resistance across injector connector terminals. If resistance is not as specified in INJECTOR RESISTANCE SPECIFICATIONS table, replace injector. If resistance is okay, remove injector. If nozzle is clogged, replace injector.

INJECTOR RESISTANCE SPECIFICATIONS

AIR REGULATOR SYSTEM TEST (NX & SENTRA)

1. Start engine and bring to operating temperature. Disconnect Auxiliary Air Control (AAC) valve harness connector. Pinch air regulator hose closed. Engine RPM should not drop. If RPM drops, go to next step. If RPM does not drop, system is functioning properly.
2. Turn ignition off. Disconnect air regulator harness connector. Measure voltage between ground and air regulator harness connector Black/Red wire. Turn ignition on. Battery voltage should be present for 5 seconds after ignition is turned on. If voltage is as specified, go to next step. If voltage is not as specified, check continuity of Black/Red wire between air regulator harness connector and fuel pump relay. Repair or replace harness or connectors as necessary. If continuity is okay, check fuel pump relay. See «RELAYS»(ref-17400-S12256886262000122900000) under RELAYS & SOLENOIDS.
3. Turn ignition off. Check continuity between ground and air regulator harness connector Black wire. Continuity should exist. If continuity exists, check air regulator. See AIR REGULATOR TEST (EXCEPT ALTIMA & MAXIMA). If continuity does not exist, repair open in Black wire.

AIR REGULATOR SYSTEM TEST (PATHFINDER, PICKUP 3.0L, QUEST, 240SX & 300ZX)

1. Turn ignition on. Pinch fuel feed hose with fingers to feel fuel pulsations or listen for fuel pump operating sound. Fuel pump should operate for 5 seconds after ignition is turned on. If fuel pump does not operate, See FUEL PUMP under FUEL DELIVERY SYSTEM. If fuel pump operates, go to next step.
2. Turn ignition off. Disconnect air regulator harness connector. Measure voltage between ground and air regulator harness connector White/Blue wire (Pathfinder and Pickup 3.0L), Blue/Red wire (Quest), Black/Pink wire (240SX), or Orange wire (300ZX).
3. Turn ignition on. Battery voltage should be present for 5 seconds after ignition is turned on. If voltage is as specified, go to next step. If voltage is not as specified, check continuity of White/Blue wire (Pathfinder and Pickup 3.0L), Blue/Red wire (Quest), Black/Pink wire (240SX), or Orange wire (300ZX) between air regulator harness connector and fuel pump relay. Repair or replace harness or connectors as necessary. If continuity is okay, check fuel pump relay. See «RELAYS»(ref-17400-S12256886262000122900000) under RELAYS & SOLENOIDS.
4. Turn ignition off. Check continuity between ground and air regulator harness connector Black wire. Continuity should exist. If continuity exists, check air regulator. See AIR REGULATOR TEST (EXCEPT ALTIMA & MAXIMA). If continuity does not exist, repair open in Black wire.

AIR REGULATOR TEST (ALTIMA & MAXIMA)

Remove air regulator from engine. Check airflow through air regulator while immersed in cold or hot water. Air should flow freely at 68°F (20°C). Almost no air should flow at 176°F (80°C). If air regulator does not operate as described, replace unit.

AIR REGULATOR TEST (EXCEPT ALTIMA & MAXIMA)

Measure resistance across air regulator connector terminals. If resistance is not about 70-80 ohms, replace air regulator. If resistance is okay, ensure air passage is not obstructed.

AUXILIARY AIR CONTROL (AAC) VALVE SYSTEM TEST (ALTIMA & 240SX)

1. Start engine and bring to operating temperature. Check idle speed. See «SPECIFICATIONS»(ref-17386) article. Adjust idle speed if necessary. See «ADJUSTMENTS»(ref-17387) article.
2. Check for stored codes. See RETRIEVING CODES in appropriate TESTS W/CODES article. If Code 43 is present, repair cause of Code 43 before continuing. If Code 43 is not present, disconnect throttle position sensor harness connector. If idle speed does not drop, go to next step. If idle speed drops, system is functioning properly.
3. Turn ignition off. Disconnect AAC valve harness connector. Turn ignition on. Measure voltage between ground and AAC valve harness connector Yellow wire (Altima) or Red/Green wire (240SX). Battery voltage should be present. If battery voltage is present, go to next step. If battery voltage is not present, check 10-amp fuse and 75-amp fusible link located in engine compartment fuse box. If fuse and fusible link are okay, repair or replace harness or connectors between AAC valve and fuse box.
4. Turn ignition off. Disconnect ECM harness connector. Check continuity between ECM harness connector terminal No. 113 (Sky Blue wire) and AAC valve harness connector Sky Blue wire (Altima) or Red/White wire (240SX). Continuity should exist. If continuity exists, check AAC valve. See AUXILIARY AIR CONTROL (AAC) VALVE TEST (EXCEPT MAXIMA VG30E). If AAC valve is okay, check ECM pin terminals and ECM harness connector terminals for damage or corrosion. Repair as necessary. If continuity does not exist, repair open in harness or connectors.

AUXILIARY AIR CONTROL (AAC) VALVE SYSTEM TEST (NX, SENTRA, PATHFINDER & PICKUP)

1. Start engine and bring to operating temperature. Check idle speed. See SERVICE & ADJUSTMENTS SPECIFICATIONS article. Adjust idle speed if necessary. See «ADJUSTMENTS»(ref-17387) article.
2. Disconnect AAC valve harness connector. Idle speed should drop. If idle speed drops, system is functioning properly. If idle speed does not drop, turn ignition off. With AAC valve harness connector disconnected, turn ignition on.
3. Measure voltage between ground and AAC valve harness connector White/Green wire (NX 1.6L and Sentra 1.6L), Red/Black wire (NX 2.0L and Sentra 2.0L) or Black/White wire (Pathfinder and Pickup). Battery voltage should be present. If battery voltage is present, go to next step. If battery voltage is not present, check 10-amp fuse located in fuse and relay box under left instrument panel. If fuse is okay, repair or replace harness or connectors between AAC valve and fuse box.
4. Turn ignition off. Disconnect ECM harness connector. Check continuity between ECM harness connector terminal No. 113 (Sky Blue wire on NX and Sentra), Orange wire (Pathfinder and Pickup 3.0L) or (White/Green wire on Pickup 2.4L) and corresponding wire of AAC valve harness connector. Continuity should exist. If continuity exists, check AAC valve. See AUXILIARY AIR CONTROL (AAC) VALVE TEST (EXCEPT MAXIMA VG30E). If AAC valve is okay, check ECM pin terminals and ECM harness connector terminals for damage or corrosion. Repair as necessary. If continuity does not exist, repair open in harness or connectors.

AUXILIARY AIR CONTROL (AAC) VALVE SYSTEM TEST (QUEST & 300ZX)

1. Start engine and bring to operating temperature. Check idle speed. See SERVICE & ADJUSTMENTS SPECIFICATIONS article. Adjust idle speed if necessary. See «ADJUSTMENTS»(ref-17387) article.
2. Disconnect AAC valve harness connector. Idle speed should drop. If idle speed drops, system is functioning properly. If idle speed does not drop, turn ignition off. With AAC valve harness connector disconnected, turn ignition on.
3. Measure voltage between ground and AAC valve harness connector White/Red wire (Quest) or Black/Red wire (300ZX). Battery voltage should be present. If battery voltage is present, go to next step. If battery voltage is not present, check harness and connectors between AAC valve harness connector and ignition switch for open. Repair or replace as necessary.
4. Turn ignition off. Disconnect ECM harness connector. Check continuity between ECM harness connector terminal No. 113 (Sky Blue wire on Quest or Green/Blue wire on 300ZX) and corresponding wire of AAC valve harness connector. Continuity should exist. If continuity exists, check AAC valve. See AUXILIARY AIR CONTROL (AAC) VALVE TEST (EXCEPT MAXIMA VG30E). If AAC valve is okay, check ECM pin terminals and ECM harness connector terminals for damage or corrosion. Repair as necessary. If continuity does not exist, repair open in harness or connectors.

AUXILIARY AIR CONTROL (AAC) VALVE TEST (EXCEPT MAXIMA VG30E)

To test AAC valve, check resistance across AAC valve connector terminals. If resistance is not approximately 10 ohms, replace AAC valve. Ensure plunger does not stick and plunger spring is not broken.

Note. On Maxima VG30E, AAC valve is a stepper motor with multiple sets of windings.

AUXILIARY AIR CONTROL (AAC) VALVE SYSTEM TEST (MAXIMA VG30E)

1. Start engine and bring to operating temperature. Turn diagnostic test mode selector on ECM fully clockwise. ECM is located under center of instrument panel. Turn air conditioner switch on. Engine speed should drop. Go to next step.
2. Turn air conditioner switch off. Turn diagnostic mode selector on ECM fully counterclockwise. Turn air conditioner switch on. Engine speed should not change. If engine speed dropped in step 1) and did not change in step 2), system is functioning properly. If not, go to next step.
3. Turn air conditioner switch off. Measure voltage between ground and ECM harness connector terminals No. 4 (Yellow/Black wire),No. 5 (Yellow/Red wire), No. 14 (Yellow wire) and No. 15 (Yellow/Blue wire). see scheme 1and see scheme 2. Race engine under no-load. Voltage should change when racing engine. Stop engine and turn ignition on.
4. Measure voltage between ground and ECM harness connector terminals No. 4 (Yellow/Black wire), No. 5 (Yellow/Red wire), No. 14 (Yellow wire) and No. 15 (Yellow/Blue wire). Battery voltage should be present. If voltage is not as specified, go to next step. If voltage is as specified, ensure ECM harness connector is connected properly.
5. Turn ignition off. Disconnect AAC valve harness connector. Turn ignition on. Measure voltage between ground and AAC harness connector terminal White/Black wire (2 wires). Battery voltage should be present. If battery voltage is present, go to step 7). If battery voltage is not present, go to next step.
6. Turn ignition off. Ensure AAC valve harness connector is disconnected. Turn ignition on. Check continuity between AAC valve harness connector White/Black wire and battery positive White/Red wire. Continuity should exist. If continuity does not exist, check Brown fusible link located in fusible link and relay box next to battery. Repair or replace as necessary. Check ECM (ECCS) relay located in fusible link and relay box next to battery. See «RELAYS»(ref-17400-S12256886262000122900000) under RELAYS & SOLENOIDS. Repair/replace as necessary. If ECM relay and Brown fusible link are okay, repair open in harness. See WIRING DIAGRAMS article.
7. Turn ignition off. Disconnect ECM harness connector. Check continuity between ECM harness connector terminal No. 4 (Yellow/Black wire) and AAC valve harness connector Yellow/Black wire. Check continuity between ECM harness connector terminal No. 5 (Yellow/Red wire) and AAC valve harness connector Yellow/Red wire. Check continuity between ECM harness connector terminal No. 14 (Yellow wire) and AAC valve harness connector Yellow wire.
8. Check continuity between ECM harness connector terminal No. 15 (Yellow/Blue wire) and AAC valve harness connector Yellow/Blue wire. Continuity should exist in all checks. If continuity does not exist, repair open in appropriate wire. If continuity exists, check AAC valve. See AUXILIARY AIR CONTROL (AAC) VALVE TEST (MAXIMA VG30E).

AUXILIARY AIR CONTROL (AAC) VALVE TEST (MAXIMA VG30E)

Check resistance between terminals No. 1 and 2; 2 and 3; 4 and 5; and 5 and 6 of AAC valve connector. (Scheme 59) If resistance is not 27-40 ohms at 68°F (20°C), replace AAC valve.

Scheme 59

Note. Diagnostic procedures for Fast Idle Control Device (FICD) systems on Altima, Maxima, NX, Pathfinder, Pickup, Sentra and 240SX are not available from manufacturer.

FAST IDLE CONTROL DEVICE (FICD) SYSTEM TEST (QUEST)

1. Start engine and warm to operating temperature. Check idle speed. See «SPECIFICATIONS»(ref-17386) article. Adjust idle speed if necessary. See «ADJUSTMENTS»(ref-17387) article. Turn air conditioning and blower fan switches on. Idle speed should increase. If idle speed does not increase, go to next step. If idle speed increases, system is functioning properly.
2. Ensure air conditioner compressor is functioning. If compressor is not functioning, repair air conditioner system as necessary. If compressor is functioning, turn ignition off. Disconnect FICD relay. Relay is located in relay box on right front inner fender rail.
3. Turn ignition on. Measure voltage between ground and FICD relay harness connector terminals No. 2 (Blue wire) and No. 5 (Blue wire). For connector identification (Scheme 56) Battery voltage should be present. If battery voltage is present, go to next step. If battery voltage is not present, check 10-amp fuse located in main fuse box under left side of instrument panel. If fuse is okay, repair open in harness between fuse and FICD relay.
4. Turn ignition off. Disconnect FICD solenoid harness connector. Check continuity between ground and FICD solenoid harness connector Black wire. Check continuity between FICD solenoid harness connector Blue/Yellow wire and FICD relay harness connector terminal No. 3 (Blue/Yellow wire). Continuity should exist. If continuity exists, go to next step. If continuity does not exist, repair open in Blue/Yellow wire or connectors.
5. Turn ignition on. Measure voltage between ground and FICD relay harness connector terminal No. 1 (White/Red wire). With air conditioner switch on and fan switch in any position except off, less than 2.3 volts should be present. With air conditioning switch off, 7-9 volts should be present. If voltage is as specified, go to next step. If voltage is not as specified, repair open in White/Red wire between FICD relay harness connector and air conditioner system.
6. Check FICD relay. See RELAYS under «RELAYS & SOLENOIDS»(ref-17400-S26910750242000122900000). If relay is okay, check FICD solenoid. See FAST IDLE CONTROL DEVICE (FICD) TEST. If FICD solenoid is okay, check ECM and ECM harness connector terminal No. 41 (White/Red wire) for correct installation, damage or corrosion. Repair or replace as necessary.

FAST IDLE CONTROL DEVICE (FICD) SYSTEM TEST (300ZX)

1. Turn ignition on. With FICD solenoid connected, measure voltage between ground and FICD solenoid harness connector terminal Black/Red wire. Battery voltage should be present. If battery voltage is present, go to step 3). If battery voltage is not present, check Green fusible link located in fusible link holder next to battery. Replace fusible link as necessary.
2. Check 10-amp fuse located in fuse and relay box at left front corner of engine compartment. Replace if necessary. If Green fusible link and 10-amp fuse are okay, repair open in Black/Red wire between FICD relay harness connector and FICD solenoid harness connector.
3. Ensure ignition is off. Disconnect ECM harness connector. ECM is located behind glove box. Check continuity between ECM harness connector terminal No. 33 (Red wire) and FICD solenoid harness connector Red wire. see scheme 1and see scheme 2. Continuity should exist. If continuity exists, check FICD solenoid. See FAST IDLE CONTROL DEVICE (FICD) TEST. If continuity does not exist, repair open in Red wire between ECM harness connector and FICD solenoid harness connector.

FAST IDLE CONTROL DEVICE (FICD) TEST

Apply battery voltage across solenoid terminals. If solenoid does not operate, check for sticking plunger or broken spring. If plunger and spring are okay, replace solenoid.

Start Signal System Test (Altima)

1. Locate ECM harness connector. ECM is located under center of instrument panel (connector is on passenger's side). Measure voltage between ground and ECM harness connector terminal No. 34 (Green/Black wire). see scheme 1and see scheme 2. Turn ignition switch to START position. Battery voltage should be present in start position ONLY. Zero volts should be present in any other ignition switch position. If voltage is not as specified, go to next step. If voltage is as specified, system is functioning properly.
2. Turn ignition off. Disconnect ECM harness connector. Disconnect ignition switch harness connector. Check continuity between ECM harness connector terminal No. 34 (Green/Black wire) and ignition switch harness connector terminal No. 6 (Black/Yellow wire). (Scheme 60) Continuity should exist. If continuity exists, check ECM and ECM harness connector terminals for correct installation, damage or corrosion. Repair as necessary. If continuity does not exist, repair open in harness or connectors between ignition switch and ECM harness connector.

Scheme 60

Start Signal System Test (Maxima)

1. Locate ECM harness connector. ECM is located under center of instrument panel (connector is on driver's side). Measure voltage between ground and ECM harness connector terminal No. 43 (Green/White wire). see scheme 1and see scheme 2. Turn ignition switch to START position. Battery voltage should be present in start position ONLY. Zero volts should be present in any other ignition switch position. If voltage is not as specified, go to next step. If voltage is as specified, system is functioning properly.
2. Turn ignition off. Disconnect ECM harness connector. Disconnect ignition switch harness connector. Check continuity between ECM harness connector terminal No. 43 (Green/White wire) and ignition switch harness connector terminal "f" (Green/Red wire). (Scheme 61) Continuity should exist. If continuity exists, check ECM and ECM harness connector terminals for correct installation, damage or corrosion. Repair as necessary. If continuity does not exist, repair open in harness or connectors between ignition switch and ECM harness connector.

Scheme 61

Start Signal System Test (NX & Sentra)

1. Locate ECM harness connector. ECM is located under center of instrument panel (connector faces to rear of vehicle). Measure voltage between ground and ECM harness connector terminal No. 34 (Purple wire). see scheme 1and see scheme 2. Turn ignition switch to START position. Battery voltage should be present in start position ONLY. Zero volts should be present in any other ignition switch position. If voltage is not as specified, go to next step. If voltage is as specified, system is functioning properly.
2. Turn ignition off. Disconnect ECM harness connector. Disconnect ignition switch harness connector. Check continuity between ECM harness connector terminal No. 34 (Purple wire) and ignition switch harness connector terminal "f" (Black/Yellow wire). (Scheme 61) Continuity should exist. If continuity exists, check ECM and ECM harness connector terminals for correct installation, damage or corrosion. Repair as necessary. If continuity does not exist, repair open in harness or connectors between ignition switch and ECM harness connector.

Start Signal System Test (Pathfinder & Pickup)

1. Locate ECM harness connector. ECM is located under passenger's seat. Measure voltage between ground and ECM harness connector terminal No. 34 (Black/Yellow wire). see scheme 1and see scheme 2. Turn ignition switch to START position. Battery voltage should be present in start position ONLY. Zero volts should be present in any other ignition switch position.
2. If voltage is not as specified, repair open in Black/Yellow wire between ECM and ignition switch. If voltage is as specified, check ECM and ECM harness connector terminals for correct installation, damage or corrosion. Repair as necessary.
3. Turn ignition on. Perform Mode IV (switch check). Refer to TESTS W/CODES article. Ensure Red LED is on while ignition switch in START position. If Red LED is on, system is functioning properly. If Red LED is not on, repeat step 1).

Start Signal System Test (Quest)

1. Locate ECM harness connector. ECM is located behind glove box. Measure voltage between ground and ECM harness connector terminal No. 34 (Blue/Black wire). see scheme 1and see scheme 2. Turn ignition switch to START position. Battery voltage should be present in start position ONLY. Zero volts should be present in any other ignition switch position. If voltage is not as specified, go to next step. If voltage is as specified, system is functioning properly.
2. Turn ignition off. Disconnect ECM harness connector. Disconnect ignition switch harness connector. Check continuity between ECM harness connector terminal No. 34 (Blue/Black wire) and ignition switch harness connector terminal "f" (Red/Green wire). (Scheme 62) Continuity should exist. If continuity exists, check ECM and ECM harness connector terminals for correct installation, damage or corrosion. Repair as necessary. If continuity does not exist, repair open in harness or connectors between ignition switch and ECM harness connector. Check 10-amp fuse located in fuse box under left instrument panel. Repair or replace as necessary.

Scheme 62

Start Signal System Test (240SX)

1. Locate ECM harness connector. ECM is located behind passenger side kick panel. Measure voltage between ground and ECM harness connector terminal No. 34 (Orange wire). see scheme 1and see scheme 2. Turn ignition switch to START position. Battery voltage should be present in start position ONLY. Zero volts should be present in any other ignition switch position. If voltage is not as specified, go to next step. If voltage is as specified, system is functioning properly.
2. Turn ignition off. Disconnect ECM harness connector. Disconnect ignition switch harness connector. Check continuity between ECM harness connector terminal No. 34 (Orange wire) and ignition switch harness connector terminal "f" (Black/Yellow wire). For ignition switch connector identification (Scheme 61) Continuity should exist. If continuity exists, check ECM and ECM harness cconnector terminals for correct installation, damage or corrosion. Repair as necessary. If continuity does not exist, repair open in harness or connectors between ignition switch and ECM harness connector. Check 10-amp fuse located in fuse box under left instrument panel. Repair or replace as necessary.

Start Signal System Test (300ZX)

1. Locate ECM harness connector. ECM is located below glove box. Measure voltage between ground and ECM harness connector terminal No. 43 (Black/Yellow wire). see scheme 1and see scheme 2. Turn ignition switch to START position. Battery voltage should be present in start position ONLY. Zero volts should be present in any other ignition switch position. If voltage is not as specified, go to next step. If voltage is as specified, system is functioning properly.
2. Turn ignition off. Disconnect ECM harness connector. Disconnect ignition switch harness connector. Disconnect battery B + terminal connector at battery (White wire). Check continuity between ECM harness connector terminal No. 43 (Black/Yellow wire) and ignition switch harness connector terminal No. 5 (Black/Yellow wire). (Scheme 63) Continuity should exist. If continuity exists, check ECM and ECM harness connector terminals for correct installation, damage or corrosion. Repair as necessary. If continuity does not exist, repair open in harness or connectors between ignition switch and ECM harness connector.
3. Check continuity between ignition switch harness connector terminal No. 1 (White wire) and battery B + terminal connector at battery (White wire). (Scheme 63) Continuity should exist. If continuity does not exist, repair open in harness or connectors between ignition switch and battery B + terminal connector at battery (White wire). Check Green fusible link located in fusible link holder next to battery. Check 10-amp fuse located in fuse box under left instrument panel. Repair or replace as necessary.

Scheme 63

EGR System Test (Altima & 240SX - Non-California)

1. Start engine and bring to operating temperature. Using a mirror or finger, ensure EGR valve plunger moves up and down as engine is accelerated from idle to 2000 RPM and back to idle. If plunger does not move up and down, go to next step. If plunger moves up and down, system is functioning properly.
2. Disconnect vacuum hose from EGR valve. Vacuum should not be present at idle. Vacuum should be present at 2000 RPM. If vacuum is not present as described, go to next step. If vacuum is present as described, check EGR valve. See EGR VALVE. Check EGR backpressure transducer. See EGR BACKPRESSURE TRANSDUCER (EGR-BPT). Replace malfunctioning components.
3. Measure voltage between ground and ECM harness connector terminal No. 105 (Light Green wire). see scheme 1and see scheme 2. ECM is located under center of instrument panel (connector is on passenger's side) on Altima or behind passenger side kick panel on 240SX. Start engine. At idle, zero volts should be present. At 2000 RPM, battery voltage should be present. If voltage is not as specified, go to next step. If voltage is as specified, check vacuum hose for clogging, cracks and proper connection. Replace hose as necessary.
4. Turn ignition off. Disconnect EGR and canister control solenoid harness connector. Solenoid is located near EGR-BPT on Altima or rear of cylinder head on 240SX. Turn ignition on. Measure voltage between ground and EGR and canister control solenoid harness connector Green/Yellow wire (Altima) or Brown wire (240SX). Battery voltage should be present. If battery voltage is present, go to step 6).
5. If battery voltage is not present, check 10-amp fuse located in fuse box under left instrument panel on Altima or in relay box next to battery on 240SX. Replace fuse if necessary. If fuse is okay, repair open in Green/Yellow wire (Altima) or Brown wire (240SX) between fuse and solenoid.
6. Turn ignition off. Disconnect ECM harness connector. Check continuity between ECM harness connector terminal No. 105 (Light Green wire) and EGR and canister control solenoid harness connector Light Green wire. Continuity should exist. If continuity exists, check solenoid valve. See EGR CONTROL SOLENOID. Replace solenoid as necessary. If solenoid is okay, check ECM and ECM harness connector for damage or improper connection. If continuity does not exist, repair open in Light Green wire.

EGR System Test (Maxima VE30DE - Non-California)

1. Start engine and bring to operating temperature. Check ECM for stored codes. See RETRIEVING CODES in TESTS W/CODES article. If Code 12 is present, repair cause of Code 12 before continuing. Using a mirror or finger, ensure EGR valve plunger moves up and down as engine is accelerated from idle to 2000 RPM and back to idle. If plunger does not move up and down, go to next step. If plunger moves up and down, system is functioning properly.
2. Disconnect vacuum hose from EGR valve. Vacuum should not be present at idle. Vacuum should be present at 2000 RPM. If vacuum is not present as described, go to next step. If vacuum is present as described, check EGR valve. See EGR VALVE. Replace EGR valve as necessary.
3. Measure voltage between ground and ECM harness connector terminal No. 102 (Yellow/Black wire). see scheme 1and see scheme 2. ECM is located under center of instrument panel (connector is on driver's side). Start engine. At idle, zero volts should be present. At 2000 RPM, battery voltage should be present. If voltage is not as specified, go to next step. If voltage is as specified, check vacuum hose for clogging, cracks and proper connection. Replace hose as necessary.
4. Turn ignition off. Disconnect EGR control solenoid harness connector. Solenoid is located near EGR valve. Turn ignition on. Measure voltage between ground and EGR control solenoid harness connector Red/Black wire. Battery voltage should be present. If battery voltage is present, go to next step. If battery voltage is not present, check 10-amp fuse located in fuse box under left instrument panel. Replace fuse if necessary. If fuse is okay, repair open in Red/Black wire between fuse and solenoid.
5. Turn ignition off. Disconnect ECM harness connector. Check continuity between ECM harness connector terminal No. 102 (Yellow/Black wire) and EGR control solenoid harness connector Yellow/Black wire. Continuity should exist. If continuity exists, check solenoid valve. See EGR CONTROL SOLENOID. Replace solenoid as necessary. If solenoid is okay, check ECM and ECM harness connector for damage or improper connection. If continuity does not exist, repair open in Yellow/Black wire.

EGR System Test (Maxima VG30E - Non-California)

Use Code 32 diagnostic procedures. See CODE 32 diagnostic procedures in TESTS W/CODES article.

EGR System Test (NX & Sentra - Non-California)

1. Start engine and bring to operating temperature. Check ECM for stored codes. See RETRIEVING CODES in TESTS W/CODES article. If Code 12 is present, repair cause of Code 12 before continuing. Using a mirror or finger, ensure EGR valve plunger moves up and down as engine is accelerated from idle to 2000 RPM and back to idle. If plunger does not move up and down, go to next step. If plunger moves up and down, system is functioning properly.
2. Disconnect vacuum hose from EGR valve. Vacuum should not be present at idle and above 4000 RPM. Vacuum should be present at 2000 RPM. If vacuum is not present as described, go to next step. If vacuum is present as described, check EGR valve. See EGR VALVE. Check EGR backpressure transducer. See EGR BACKPRESSURE TRANSDUCER (EGR-BPT). Replace malfunctioning components.
3. Measure voltage between ground and ECM harness connector terminal No. 105 (Red/Blue wire 1.6L or Gray wire 2.0L). see scheme 1and see scheme 2. ECM is located under center of instrument panel. Start engine. At 4000 RPM, voltage should be 0.6-0.8 volt. At 2000 RPM, battery voltage should be present. If voltage is not as specified, go to next step. If voltage is as specified, check vacuum hose for clogging, cracks and proper connection. Replace hose as necessary.
4. Turn ignition off. Disconnect EGR and canister control solenoid harness connector. Solenoid is located near EGR valve. Turn ignition on. Measure voltage between ground and EGR and canister control solenoid harness connector White/Green wire. Battery voltage should be present. If battery voltage is present, go to next step. If battery voltage is not present, check 10-amp fuse located in fuse box under left instrument panel. Replace fuse if necessary. If fuse is okay, repair open in White/Green wire between fuse and solenoid.
5. Turn ignition off. Disconnect ECM harness connector. Check continuity between ECM harness connector terminal No. 105 (Red/Blue wire on 1.6L or Gray wire on 2.0L) and EGR and canister control solenoid harness connector (Red/Blue wire on 1.6L or Gray wire on 2.0L). Continuity should exist. If continuity exists, check solenoid valve. See EGR CONTROL SOLENOID. Replace solenoid as necessary. If solenoid is okay, check ECM and ECM harness connector for damage or improper connection. If continuity does not exist, repair open in Red/Blue wire on 1.6L or Gray wire on 2.0L.

EGR System Test (Pathfinder & Pickup - Non-California)

1. Start engine and bring to operating temperature. Check ECM for stored codes. See RETRIEVING CODES in TESTS W/CODES article. If Code 12 is present, repair cause of Code 12 before continuing. Using a mirror or finger, ensure EGR valve plunger moves up and down as engine is accelerated from idle to 2000 RPM and back to idle. If plunger does not move up and down, go to next step. If plunger moves up and down, system is functioning properly.
2. Disconnect vacuum hose from EGR valve. Vacuum should not be present at idle. Vacuum should be present at 2000 RPM. If vacuum is not present as described, go to next step. If vacuum is present as described, check EGR valve. See EGR VALVE. Check EGR backpressure transducer. See EGR BACKPRESSURE TRANSDUCER (EGR-BPT). Replace malfunctioning components.
3. Measure voltage between ground and ECM harness connector terminal No. 102 (Blue/White wire on Pathfinder and Pickup 3.0L) or terminal No. 105 (White/Blue wire on Pickup 2.4L). see scheme 1and see scheme 2. ECM is located under passenger's seat. Start engine. At idle, zero volts should be present. At 2000 RPM, battery voltage should be present. If voltage is not as specified, go to next step. If voltage is as specified, check vacuum hose for clogging, cracks and proper connection. Replace hose as necessary.
4. Turn ignition off. Disconnect EGR control solenoid harness connector. Solenoid is located near EGR valve. Turn ignition on. Measure voltage between ground and EGR control solenoid harness connector Black/White wire. Battery voltage should be present. If battery voltage is present, go to next step. If battery voltage is not present, check 15-amp fuse located in fuse box under left instrument panel. Replace fuse if necessary. If fuse is okay, repair open in Black/White wire between fuse and solenoid.
5. Turn ignition off. Disconnect ECM harness connector. Check continuity between ECM harness connector terminal No. 102 (Blue/White wire on Pathfinder and Pickup 3.0L) or terminal No. 105 (White/Blue wire on Pickup 2.4L) and corresponding wire of EGR control solenoid harness connector. Continuity should exist. If continuity exists, check solenoid valve. See EGR CONTROL SOLENOID. Replace solenoid as necessary. If solenoid is okay, check ECM and ECM harness connector for damage or improper connection. If continuity does not exist, repair open in Blue/White wire on Pathfinder and Pickup 3.0L or White/Blue wire on Pickup 2.4L.

EGR System Test (Quest - Non-California)

1. Start engine and bring to operating temperature. Check ECM for stored codes. See RETRIEVING CODES in TESTS W/CODES article. If Code 12 is present, repair cause of Code 12 before continuing. Using a mirror or finger, ensure EGR valve plunger moves up and down as engine is accelerated from idle to 2000 RPM and back to idle. If plunger does not move up and down, go to next step. If plunger moves up and down, system is functioning properly.
2. Disconnect vacuum hose from EGR valve. Vacuum should not be present at idle. Vacuum should be present at 2000 RPM. If vacuum is not present as described, go to next step. If vacuum is present as described, check EGR valve. See EGR VALVE. Replace EGR valve as necessary.
3. Measure voltage between ground and ECM harness connector terminal No. 102 (Gray wire). see scheme 1and see scheme 2. ECM is located behind glove box. Start engine. At idle, zero volts should be present. At 2000 RPM, battery voltage should be present. If voltage is not as specified, go to next step. If voltage is as specified, check vacuum hose for clogging, cracks and proper connection. Replace hose as necessary.
4. Turn ignition off. Disconnect EGR control solenoid harness connector. Solenoid is located below throttle body. Turn ignition on. Measure voltage between ground and EGR control solenoid harness connector White/Red wire. Battery voltage should be present. If battery voltage is present, go to next step. If battery voltage is not present, repair open in White/Red wire between solenoid and ignition switch.
5. Turn ignition off. Disconnect ECM harness connector. Check continuity between ECM harness connector terminal No. 102 (Gray wire) and EGR control solenoid harness connector Gray wire. Continuity should exist. If continuity exists, check solenoid valve. See EGR CONTROL SOLENOID. Replace solenoid as necessary. If solenoid is okay, check ECM and ECM harness connector for damage or improper connection. If continuity does not exist, repair open in Gray wire.

EGR System Test (300ZX - Non-California)

Use Code 32 diagnostic procedures. See CODE 32 diagnostic procedures in TESTS W/CODES article.

Pulsed Secondary Air Injection (PAIR) System Test (NX & Sentra 2.0L)

1. Start engine and warm to operating temperature. Enter self-diagnostic Mode II. See TESTS W/CODES article. Run engine at approximately 2000 RPM for 2 minutes under no-load. Ensure Red LED on ECM or CHECK ENGINE light flashes more than 5 times during a 10 second period with engine running at 2000 RPM. If Red LED or CHECK ENGINE light does not flash as described, see FEEDBACK SYSTEM under «FUEL CONTROL»(ref-17400-S38578761052000122900000). If Red LED or CHECK ENGINE light flashes as described, go to next step.
2. Release accelerator pedal and let engine idle. Disconnect PAIR valve inlet hose (top hose). Listen to PAIR valve operating sound. With engine idling and during deceleration, PAIR valve should operate. When accelerator pedal is depressed, PAIR valve should not operate. If PAIR valve does not operate as described, go to next step. If PAIR valve operates as described, system is functioning properly.
3. Disconnect vacuum hose at PAIR valve. With engine idling and during deceleration, vacuum should exist. When accelerator pedal is depressed, vacuum should not exist. If vacuum does not exist as described, go to next step. If vacuum exists as described, check PAIR valve. See PULSED SECONDARY AIR INJECTION (PAIR) VALVE TEST.
4. Locate ECM harness connector. ECM is located under center of instrument panel (connector faces to rear of vehicle). Measure voltage between ground and ECM harness connector terminal No. 102 (Pink wire). see scheme 1and see scheme 2. With engine idling and during deceleration, 0.6-0.8 volt should be present. When accelerator pedal is depressed, battery voltage should be present. If voltage is not as described, go to next step. If voltage is as described, check vacuum hose for clogging, cracks and proper connection.
5. Turn ignition off. Disconnect PAIR control solenoid harness connector. Solenoid is attached to bracket next to EGR backpressure transducer. Turn ignition on. Measure voltage between ground and PAIR control solenoid harness connector White/Green wire. Battery voltage should be present. If battery voltage is present, go to next step. If battery voltage is not present, check 10-amp fuse located in fuse box under left of instrument panel. Replace fuse as necessary. If fuse is okay, repair open in Green/White wire between PAIR control solenoid and fuse.
6. Turn ignition off. Disconnect ECM harness connector. Check continuity between ECM harness connector terminal No. 102 (Pink wire) and PAIR control solenoid harness connector Pink wire. Continuity should exist. If continuity exists, go to next step. If continuity does not exist, repair open in Pink wire between ECM and PAIR control solenoid.
7. Check PAIR control solenoid. See PULSED SECONDARY AIR INJECTION (PAIR) CONTROL SOLENOID TEST. Replace solenoid as necessary. If solenoid is okay, check ECM and ECM harness connector terminals for damage, corrosion and proper connection. Repair or replace as necessary.

Pulsed Secondary Air Injection (PAIR) System Test (Pickup 2.4L)

1. Start engine and warm to operating temperature. Enter self-diagnostic Mode II. See TESTS W/CODES article. Run engine at approximately 2000 RPM for 2 minutes under no-load. Ensure Green LED on ECM flashes more than 5 times during a 10 second period with engine running at 2000 RPM. If Green LED does not flash as described, see FEEDBACK SYSTEM under FUEL CONTROL under «FUEL SYSTEM»(ref-17400-S06141642372000122900000). If Green LED flashes as described, go to next step.
2. Release accelerator pedal and let engine idle. Disconnect PAIR valve inlet hose (top hose). Listen to PAIR valve operating sound. With engine idling, PAIR valve should operate. When accelerator pedal is depressed, PAIR valve should not operate. If PAIR valve does not operate as described, go to next step. If PAIR valve operates as described, system is functioning properly.
3. Disconnect vacuum hose at PAIR valve. PAIR valve is located in left front corner of engine compartment. With engine idling, vacuum should exist. When accelerator pedal is depressed, vacuum should not exist. If vacuum does not exist as described, go to next step. If vacuum exists as described, check PAIR valve. See PULSED SECONDARY AIR INJECTION (PAIR) VALVE TEST.
4. Locate ECM harness connector. ECM is located under passenger's seat. Measure voltage between ground and ECM harness connector terminal No. 102 (Light Green wire). see scheme 1and see scheme 2. With engine idling, zero volts should be present. When accelerator pedal is depressed, battery voltage should be present. If voltage is not as described, go to next step. If voltage is as described, check vacuum hose for clogging, cracks and proper connection.
5. Turn ignition off. Disconnect PAIR control solenoid harness connector. Solenoid is located next to PAIR valve. Turn ignition on. Measure voltage between ground and PAIR control solenoid harness connector Black/White wire. Battery voltage should be present. If battery voltage is present, go to next step. If battery voltage is not present, check 10-amp fuse located in fuse box under left of instrument panel. Replace fuse as necessary. If fuse is okay, repair open in Black/White wire between PAIR control solenoid and fuse.
6. Turn ignition off. Disconnect ECM harness connector. Check continuity between ECM harness connector terminal No. 102 (Light Green wire) and PAIR control solenoid harness connector Light Green wire. Continuity should exist. If continuity exists, go to next step. If continuity does not exist, repair open in Light Green wire between ECM and PAIR control solenoid.
7. Check PAIR control solenoid. See PULSED SECONDARY AIR INJECTION (PAIR) CONTROL SOLENOID TEST. Replace solenoid as necessary. If solenoid is okay, check ECM and ECM harness connector terminals for damage, corrosion and proper connection. Repair or replace as necessary.

Pulsed Secondary Air Injection (PAIR) System Test (240SX)

1. Start engine and warm to operating temperature. Run engine at approximately 2000 RPM for 2 minutes under no-load. Release accelerator pedal and let engine idle. Disconnect PAIR valve inlet hose (top hose). Listen to PAIR valve operating sound. With engine idling and during deceleration, PAIR valve should operate. When accelerator pedal is depressed, PAIR valve should not operate. If PAIR valve does not operate as described, go to next step. If PAIR valve operates as described, system is functioning properly.
2. Disconnect vacuum hose at PAIR valve. PAIR valve is located at left side of engine compartment, near brake master cylinder. With engine idling and during deceleration, vacuum should exist. When accelerator pedal is depressed, vacuum should not exist. If vacuum does not exist as described, go to next step. If vacuum exists as described, check PAIR valve. See PULSED SECONDARY AIR INJECTION (PAIR) VALVE TEST.
3. Locate ECM harness connector. ECM is located behind passenger side kick panel. Measure voltage between ground and ECM harness connector terminal No. 102 (Pink wire). see scheme 1and see scheme 2. With engine idling and during deceleration, zero volts should be present. When accelerator pedal is depressed, battery voltage should be present. If voltage is not as described, go to next step. If voltage is as described, check vacuum hose for clogging, cracks and proper connection.
4. Turn ignition off. Disconnect PAIR control solenoid harness connector. Solenoid is located next to PAIR valve. Turn ignition on. Measure voltage between ground and PAIR control solenoid harness connector Brown wire. Battery voltage should be present. If battery voltage is present, go to next step. If battery voltage is not present, check 10-amp fuse located in relay box next to battery. Replace fuse as necessary. If fuse is okay, repair open in Brown wire between PAIR control solenoid and fuse.
5. Turn ignition off. Disconnect ECM harness connector. Check continuity between ECM harness connector terminal No. 102 (Pink wire) and PAIR control solenoid harness connector Pink wire. Continuity should exist. If continuity exists, go to next step. If continuity does not exist, repair open in Pink wire between ECM and PAIR control solenoid.
6. Check PAIR control solenoid. See PULSED SECONDARY AIR INJECTION (PAIR) CONTROL SOLENOID TEST. Replace solenoid as necessary. If solenoid is okay, check ECM and ECM harness connector terminals for damage, corrosion and proper connection. Repair or replace as necessary.

Pulsed Secondary Air Injection (PAIR) Valve Test

Apply vacuum to PAIR valve diaphragm. (Scheme 64) Apply light air pressure to air cleaner side of PAIR valve. Air should flow toward exhaust manifold side. Air should NOT flow in opposite direction. If PAIR valve does not operate as described, replace valve.

Scheme 64

Note. On some Pulsed Secondary Air Injection (PAIR) control solenoids, port "C" may be a vent that is capped with a filter. Also, if solenoid does not respond as specified, perform test again, considering port "A" as port "B" and vice versa.

Pulsed Secondary Air Injection (PAIR) Control Solenoid Test

1. Disconnect vacuum lines and electrical connector from solenoid. Remove solenoid. Connect hand-held vacuum pump to vacuum port "B" of solenoid. (Scheme 65) Apply vacuum. Vacuum should now be available at port "C", but not at port "A".
2. Apply battery voltage across solenoid connector terminals, ensuring polarity is correct to prevent solenoid damage. Vacuum should now be available at port "A", but not at port "C". Replace solenoid if it does not operate as specified.

Scheme 65

Condenser (Cooling) Fan Control Test

1. Start engine and warm to operating temperature. Set temperature lever to full cold. Turn A/C switch on. Turn fan switch on. Run engine at idle with A/C on for several minutes. Ensure condenser fan operates. If fan does not operate, go to next step. If fan operates, system is functioning properly.
2. Turn A/C and fan switches off. Turn ignition off. Disconnect condenser fan relay. (Scheme 66)and (Scheme 67). Turn ignition on. Measure voltage between ground and condenser fan relay harness connector terminals No. 2 (Blue/Orange wire) and No. 3 (Black/White wire). Battery voltage should be present. If battery voltage is present, go to step 4). If battery voltage is not present, go to next step.
3. Check Gray and Green fusible links located in fuse and relay box next to battery. Replace fusible links as necessary. Check 10-amp fuse located in fuse box under left side of instrument panel. Replace fuse as necessary. If fusible links and 10-amp fuse are okay, repair open in harness or connectors.
4. Turn ignition off. Disconnect condenser fan motor harness connector. Check continuity between condenser fan motor harness connector terminal "a" (Brown/White wire) and condenser fan relay harness connector terminal No. 5 (Brown/White wire). (Scheme 66)and (Scheme 67). Continuity should exist. If continuity exists, go to next step. If continuity does not exist, repair open in Brown/White wire.
5. Check continuity between ground and condenser fan motor harness connector terminal "b" (Black wire). (Scheme 66)and (Scheme 67). Continuity should exist. If continuity exists, go to next step. If continuity does not exist, repair open in Black wire.
6. Disconnect ECM harness connector. ECM is located behind passenger side kick panel. Check continuity between ECM harness connector terminal No. 9 (Orange/Blue wire) and condenser fan relay harness connector terminal No. 1 (Orange/Blue wire). see scheme 1and see scheme 26. Continuity should exist. If continuity exists, go to next step. If continuity does not exist, repair open in Orange/Blue wire.
7. Check condenser fan relay. See «RELAYS»(ref-17400-S12256886262000122900000) under RELAYS & SOLENOIDS. Replace relay as necessary. If relay is okay, check condenser fan motor. See CONDENSER FAN MOTOR TEST. Replace fan motor as necessary. If fan motor is okay, inspect ECM and ECM harness connector terminals for damage, corrosion and improper connection. Repair as necessary.

Condenser Fan Motor Test

Apply battery voltage across fan motor connector terminals. Fan motor should operate. If fan motor does not operate, replace fan motor.

Scheme 66

Scheme 67

Radiator (Cooling) Fan Control Test (Altima With A/C)

1. Start engine and warm to operating temperature. Set temperature lever to full cold. Turn A/C switch on. Turn fan switch on. Run engine at idle with A/C on for several minutes. Ensure radiator fan operates at low speed. If radiator fan does not operate at low speed, go to RADIATOR (COOLING) FAN LOW SPEED CONTROL TEST (ALTIMA). If radiator fan operates at low speed, go to next step.
2. Turn A/C and fan switches off. Turn ignition off. Disconnect engine coolant temperature sensor harness connector. Start engine and ensure radiator fan operates at high speed. If radiator fan does not operate at high speed, see RADIATOR (COOLING) FAN HIGH SPEED CONTROL TEST (ALTIMA). If radiator fan operates at high speed, system is functioning properly.

Radiator (Cooling) Fan Control Test (Altima Without A/C)

1. Start engine and warm to operating temperature. Ensure radiator fan operates at low speed. If radiator fan does not operate at low speed, go to RADIATOR (COOLING) FAN LOW SPEED CONTROL TEST (ALTIMA). If radiator fan operates at low speed, go to next step.
2. Turn ignition off. Disconnect engine coolant temperature sensor harness connector. Start engine and ensure radiator fan operates at high speed. If radiator fan does not operate at high speed, see RADIATOR (COOLING) FAN HIGH SPEED CONTROL TEST (ALTIMA). If radiator fan operates at high speed, system is functioning properly.

Radiator (Cooling) Fan Low Speed Control Test (Altima)

1. Turn ignition off. Disconnect radiator fan relay No. 1. (Scheme 68)- (Scheme 70). Turn ignition on. Measure voltage between ground and radiator fan relay No. 1 harness connector terminals No. 1 (White/Blue wire) and No. 3 (Green/Yellow wire). (Scheme 68)- (Scheme 70). Battery voltage should be present. If battery voltage is present, go to step 3). If battery voltage is not present, go to next step.
2. Check 10-amp fuse located in fuse box under left instrument panel. Replace fuse as necessary. Check 30-amp and 75-amp fusible links located in fusible link and fuse box left of battery. Replace fusible link(s) as necessary. If fuse and fusible links are okay, repair open in harness or connectors.
3. Turn ignition off. Disconnect radiator fan motor No. 1 and radiator fan motor No. 2 harness connectors. Check continuity between radiator fan motor No. 1 harness connector terminal "a" (White/Black wire) and radiator fan relay No. 1 harness connector terminal No. 5 (White/Black wire). Check continuity between radiator fan motor No. 2 harness connector terminal "e" (White/Black wire) and radiator fan relay No. 1 harness connector terminal No. 5 (White/Black wire). (Scheme 68)- (Scheme 70).
4. Check continuity between radiator fan motor No. 1 harness connector terminal "d" (Black wire) and ground. Check continuity between radiator fan motor No. 2 harness connector terminal "h" (Black wire) and ground. (Scheme 68)- (Scheme 70). Continuity should exist in all checks. If continuity exists in all checks, go to next step. If continuity does not exist in any check, repair open in appropriate wire or connector.
5. Disconnect ECM harness connector. ECM is located under center of instrument panel (connector is on passenger's side). Check continuity between ECM harness connector terminal No. 9 (Light Green/Red wire) and radiator fan relay No. 1 harness connector terminal No. 2 (Light Green/Red wire). see scheme 1, see scheme 2 and (Scheme 68) -33. Continuity should exist. If continuity exists, go to next step. If continuity does not exist, repair open in Light Green/Red wire or connectors between ECM and relay.
6. Check radiator fan relay No. 1. See «RELAYS»(ref-17400-S12256886262000122900000) under RELAYS & SOLENOIDS. Replace relay as necessary. If relay is okay, check fan motors. See RADIATOR FAN MOTOR TEST. Replace motor as necessary. If fan motor is okay, check ECM and ECM harness connector for damage, corrosion or improper connection. Repair as necessary.

Scheme 68

Scheme 69

Scheme 70

Radiator (Cooling) Fan High Speed Control Test (Altima)

1. Turn ignition off. Disconnect radiator fan relay No. 2 and No. 3. (Scheme 71)- (Scheme 73). Turn ignition on. Measure voltage between ground and radiator fan relay No. 2 and No. 3 harness connector terminals No. 1 (Green/Yellow wire) and No. 3 (White/Green wire). (Scheme 71)- (Scheme 73). Battery voltage should be present. If battery voltage is present, go to step 3). If battery voltage is not present, go to next step.
2. Check 10-amp fuse located in fuse box under left instrument panel. Replace fuse as necessary. Check 30-amp and 75-amp fusible links located in fusible link and fuse box left of battery. Replace fusible link(s) as necessary. If fuse and fusible links are okay, repair open in harness or connectors.
3. Turn ignition off. Disconnect radiator fan motor No. 1 and radiator fan motor No. 2 harness connectors. Check continuity between radiator fan motor No. 1 harness connector terminal "b" (White/Yellow wire) and radiator fan relay No. 2 harness connector terminal No. 5 (White/Yellow wire). Check continuity between radiator fan motor No. 2 harness connector terminal "f" (White/Blue wire) and radiator fan relay No. 3 harness connector terminal No. 5 (White/Blue wire). (Scheme 71)- (Scheme 73).
4. Check continuity between radiator fan motor No. 1 harness connector terminal "c" (White/Green wire) and radiator fan relay No. 2 harness connector No. 6 (White/Green wire). Check continuity between radiator fan motor No. 2 harness connector terminal "g" (White/Red wire) and radiator fan relay No. 2 harness connector No. 6 (White/Red wire). Check continuity between radiator fan relay No. 2 and No. 3 harness connector terminal No. 7 (Black wire) and ground. (Scheme 71)- (Scheme 73). Continuity should exist in all checks. If continuity exists in all checks, go to next step. If continuity does not exist in any check, repair open in appropriate wire or connector.
5. Disconnect ECM harness connector. ECM is located under center of instrument panel (connector is on passenger's side). Check continuity between ECM harness connector terminal No. 10 (Light Green wire) and radiator fan relays No. 2 and No. 3 harness connector terminal No. 2 (Light Green wire). see scheme 1, see scheme 2 and (Scheme 71) - (Scheme 73). Continuity should exist. If continuity exists, go to next step. If continuity does not exist, repair open in Light Green wire or connectors between ECM and relays.
6. Check radiator fan relays No. 2 and No. 3. See «RELAYS»(ref-17400-S12256886262000122900000) under RELAYS & SOLENOIDS. Replace relay(s) as necessary. If relays are okay, check fan motor(s). See RADIATOR FAN MOTOR TEST. Replace motor(s) as necessary. If fan motors are okay, check ECM and ECM harness connector for damage, corrosion or improper connection. Repair as necessary.

Scheme 71

Scheme 72

Scheme 73

Radiator (Cooling) Fan Control Test (Maxima VE30DE With A/C)

1. Start engine and warm to operating temperature. Set temperature lever to full cold. Turn A/C switch on. Turn fan switch on. Run engine at idle with A/C on for several minutes. Ensure radiator fan operates at low speed. If radiator fan does not operate at low speed, go to RADIATOR (COOLING) FAN LOW SPEED CONTROL TEST (MAXIMA VE30DE). If radiator fan operates at low speed, go to next step.
2. Turn A/C and fan switches off. Turn ignition off. Disconnect engine coolant temperature sensor harness connector. Start engine and ensure radiator fan operates at high speed. If radiator fan does not operate at high speed, see RADIATOR (COOLING) FAN HIGH SPEED CONTROL TEST (MAXIMA VE30DE). If radiator fan operates at high speed, system is functioning properly.

Radiator (Cooling) Fan Control Test (Maxima VE30DE W/O A/C)

1. Start engine and warm to operating temperature. Ensure radiator fan operates at low speed. If radiator fan does not operate at low speed, go to RADIATOR (COOLING) FAN LOW SPEED CONTROL TEST (MAXIMA VE30DE). If radiator fan operates at low speed, go to next step.
2. Turn ignition off. Disconnect engine coolant temperature sensor harness connector. Start engine and ensure radiator fan operates at high speed. If radiator fan does not operate at high speed, see RADIATOR (COOLING) FAN HIGH SPEED CONTROL TEST (MAXIMA VE30DE). If radiator fan operates at high speed, system is functioning properly.

Radiator (Cooling) Fan Low Speed Control Test (Maxima VE30DE)

1. Turn ignition off. Disconnect radiator fan relay No. 1. (Scheme 74)- (Scheme 76). Turn ignition on. Measure voltage between radiator fan relay No. 1 harness connector terminals No. 2 (White/Red wire) and No. 3 (White/Blue wire). (Scheme 74)- (Scheme 76). Battery voltage should be present. If battery voltage is present, go to step 3). If battery voltage is not present, go to next step.
2. Check 10-amp fuse located in fuse box under left instrument panel. Replace fuse as necessary. Check Blue and Red fusible links located in fusible link and fuse box at engine side of battery. Replace fusible link(s) as necessary. If fuse and fusible links are okay, repair open in harness or connectors.
3. Turn ignition off. Disconnect radiator fan motor No. 1 and radiator fan motor No. 2 harness connectors. Check continuity between radiator fan motor No. 1 harness connector terminal "a" (White/Green wire) and radiator fan relay No. 1 harness connector terminal No. 5 (White/Green wire). Check continuity between radiator fan motor No. 2 harness connector terminal "e" (White/Green wire) and radiator fan relay No. 1 harness connector terminal No. 5 (White/Green wire). (Scheme 74)- (Scheme 76).
4. Check continuity between radiator fan motor No. 1 harness connector terminal "d" (Black wire) and ground. Check continuity between radiator fan motor No. 2 harness connector terminal "h" (Black wire) and ground. (Scheme 74)- (Scheme 76). Continuity should exist in all checks. If continuity exists in all checks, go to next step. If continuity does not exist in any check, repair open in appropriate wire or connector.
5. Disconnect ECM harness connector. ECM is located under center of instrument panel (connector is on driver's side). Check continuity between ECM harness connector terminal No. 19 (Light Green/Red wire) and radiator fan relay No. 1 harness connector terminal No. 1 (Light Green/Black wire). see scheme 1, see scheme 2 and (Scheme 74) - (Scheme 76). Continuity should exist. If continuity exists, go to next step. If continuity does not exist, repair open in Light Green/Red or Light Green/Black wire (wire changes color at 8-pin harness connector) or connectors between ECM and relay.
6. Check radiator fan relay No. 1. See «RELAYS»(ref-17400-S12256886262000122900000) under RELAYS & SOLENOIDS. Replace relay as necessary. If relay is okay, check fan motors. See RADIATOR FAN MOTOR TEST. Replace motor as necessary. If fan motor is okay, check ECM and ECM harness connector for damage, corrosion or improper connection. Repair as necessary.

Scheme 74

Scheme 75

Scheme 76

Radiator (Cooling) Fan High Speed Control Test (Maxima VE30DE)

1. Turn ignition off. Disconnect radiator fan relay No. 2 and No. 3. (Scheme 77)and (Scheme 78). Turn ignition on. Measure voltage between ground and radiator fan relay No. 2 and No. 3 harness connector terminals No. 1 (White/Red wire) and No. 6 (White/Blue wire). (Scheme 77)and (Scheme 78). Battery voltage should be present. If battery voltage is present, go to step 3). If battery voltage is not present, go to next step.
2. Check 10-amp fuse located in fuse box under left instrument panel. Replace fuse as necessary. Check Blue and Red fusible links located in fusible link and fuse box at engine side of battery. Replace fusible link(s) as necessary. If fuse and fusible links are okay, repair open in harness or connectors.
3. Turn ignition off. Disconnect radiator fan motor No. 1 and radiator fan motor No. 2 harness connectors. Check continuity between radiator fan motor No. 1 harness connector terminal "b" (White/Yellow wire) and radiator fan relay No. 2 harness connector terminal No. 7 (White/Yellow wire). Check continuity between radiator fan motor No. 2 harness connector terminal "f" (White/Blue wire) and radiator fan relay No. 3 harness connector terminal No. 5 (White/Blue wire). (Scheme 77)and (Scheme 78).
4. Check continuity between radiator fan motor No. 1 harness connector terminal "c" (White/Green wire) and radiator fan relay No. 2 harness connector No. 3 (White/Black wire). Check continuity between radiator fan motor No. 2 harness connector terminal "g" (White/Red wire) and radiator fan relay No. 2 harness connector No. 3 (White/Red wire). Check continuity between radiator fan relay No. 2 and No. 3 harness connector terminal No. 5 (Black wire) and ground. (Scheme 77)and (Scheme 78). Continuity should exist in all checks. If continuity exists in all checks, go to next step. If continuity does not exist in any check, repair open in appropriate wire or connector.
5. Disconnect ECM harness connector. ECM is located under center of instrument panel (connector is on driver's side). Check continuity between ECM harness connector terminal No. 6 (Light Green/Black wire) and radiator fan relays No. 2 and No. 3 harness connector terminal No. 2 (Light Green/Red wire). see scheme 1, see scheme 2, (Scheme 77) and (Scheme 78). Continuity should exist. If continuity exists, go to next step. If continuity does not exist, repair open in Light Green/Black or Light Green/Black wire (wire changes color at 8-pin harness connector) or connectors between ECM and relays.
6. Check radiator fan relays No. 2 and No. 3. See «RELAYS»(ref-17400-S12256886262000122900000) under RELAYS & SOLENOIDS. Replace relay(s) as necessary. If relays are okay, check fan motor(s). See RADIATOR FAN MOTOR TEST. Replace motor(s) as necessary. If fan motors are okay, check ECM and ECM harness connector for damage, corrosion or improper connection. Repair as necessary.

Scheme 77

Scheme 78

Radiator (Cooling) Fan Control Test (Maxima VG30E With A/C)

1. Start engine and warm to operating temperature. Set temperature lever to full cold. Turn A/C switch on. Turn fan switch on. Run engine at idle with A/C on for several minutes. Ensure radiator fan operates at low speed. If radiator fan operates at low speed, go to RADIATOR (COOLING) FAN HIGH SPEED CONTROL TEST (MAXIMA VG30E). If radiator fan does not operate at low speed, go to next step.
2. Turn ignition off. Disconnect radiator fan relay No. 1. For relay location (Scheme 74)- (Scheme 76). Connect jumper wire between radiator fan relay No. 1 harness connector terminals No. 3 (White/Blue wire) and No. 5 (White/Green wire). Disconnect both radiator fan motor harness connectors. Turn ignition on.
3. Measure voltage between ground and each radiator fan motor harness connector terminal "a" (White/Green wire). (Scheme 79)and (Scheme 80). Battery voltage should be present. If battery voltage is present, go to next step. If battery voltage is not present, check Gray in-line fusible link located near positive battery terminal. Replace as necessary. Check Red fusible link located in fusible link box at engine side of battery. Replace as necessary. If both fusible links are okay, repair open in White/Blue wire or connectors between relay and fusible link.
4. Check radiator fan relay No. 1. See «RELAYS»(ref-17400-S12256886262000122900000) under RELAYS & SOLENOIDS. Replace relay as necessary. If relay is okay, turn ignition off. Disconnected jumper wire installed in step 2). Disconnect ECM harness connector. ECM is located under center of instrument panel (connector is on driver's side). Check continuity between ECM harness connector terminal No. 19 (Light Green/Black wire) and radiator fan relay No. 1 harness connector terminal No. 1 (Light Green/Black wire). see scheme 1, see scheme 2, (Scheme 79) and (Scheme 80). Continuity should exist. If continuity exists, go to next step. If continuity does not exist, repair open in Light Green/Black wire.
5. Check continuity between ground and each radiator fan motor harness connector terminal "d" (Black wire). Continuity should exist. If continuity exists, replace appropriate radiator fan motor. If continuity does not exist, repair open in Black wire.

Scheme 79

Scheme 80

Radiator (Cooling) Fan High Speed Control Test (Maxima VG30E)

1. Start engine. Disconnect engine coolant temperature sensor harness connector. Both radiator fan should operate at high speed. If fans do not operate at high speed, go to next step. If both fans operate at high speed, system is functioning properly.
2. Turn ignition off. Disconnect radiator fan relays No. 2 and No. 3. For relay location (Scheme 74)- (Scheme 76). Connect jumper wire between radiator fan relay No. 2 and No. 3 harness connector terminals No. 6 (White/Blue wire) and No. 7 (relay No. 2 is White/Yellow wire and relay No. 3 is White/Blue wire). Disconnect both radiator fan motor harness connectors. Turn ignition on.
3. Measure voltage between ground and each radiator fan motor harness connector terminal "b" (fan No. 1 is White/Yellow wire and fan No. 2 is White/Blue wire). (Scheme 81)and (Scheme 82). Battery voltage should be present. If battery voltage is present, go to next step. If battery voltage is not present, check Gray in-line fusible link located near positive battery terminal. Replace as necessary. Check Red fusible link located in fusible link box at engine side of battery. Replace as necessary. If both fusible links are okay, repair open in appropriate wire or connectors between relay and fusible link or between relay and fan motor.
4. Turn ignition off. Disconnected jumper wire installed in step 2). Connect jumper wire between radiator fan relay No. 2 and No. 3 harness connector terminals No. 3 (relay No. 2 is White/Black wire and relay No. 3 is White/Red wire) and No. 5 (Black wire). Check continuity between ground and each radiator fan motor harness connector terminal "c" (fan No. 1 is White/Black wire and fan No. 2 is White/Red wire). (Scheme 81)and (Scheme 82). Continuity should exist. If continuity exists, go to next step. If continuity does not exist, repair open in appropriate wire or connector.
5. Disconnected jumper wire installed in step 4). Reconnect both radiator fan motor harness connectors. Disconnect ECM harness connector. ECM is located under center of instrument panel (connector is on driver's side). Check continuity between ECM harness connector terminal No. 6 (Light Green/Red wire) and radiator fan relays No. 2 and No. 3 harness connector terminal No. 2 (Light Green/Red wire). see scheme 1, see scheme 2 and (Scheme 81) and (Scheme 82). Continuity should exist. If continuity exists, go to next step. If continuity does not exist, repair open in Light Green/Red wire.
6. Turn ignition off. Check radiator fan relays No. 2 and No. 3. See «RELAYS»(ref-17400-S12256886262000122900000) under RELAYS & SOLENOIDS. Replace relay(s) as necessary. Check fan motors No. 1 and No. 2. See RADIATOR FAN MOTOR TEST. Replace fan motor(s) as necessary.

Scheme 81

Scheme 82

Radiator (Cooling) Fan Control Test (NX & Sentra 1.6L A/T With A/C)

1. Start engine and warm to operating temperature. Set temperature lever to full cold. Turn A/C switch on. Turn fan switch on. Run engine at idle with A/C on for several minutes. Ensure radiator fan operates at low speed. If radiator fan does not operate at low speed, go to RADIATOR (COOLING) FAN LOW SPEED CONTROL TEST (NX & SENTRA - 1.6L A/T). If radiator fan operates at low speed, go to next step.
2. Turn A/C and fan switches off. Turn ignition off. Disconnect radiator fan relay No. 1. Start engine and idle until engine temperature is above 221°F (105°C). Ensure radiator fan operates at high speed. If radiator fan does not operate at high speed, see RADIATOR (COOLING) FAN HIGH SPEED CONTROL TEST (NX & SENTRA - 1.6L A/T). If radiator fan operates at high speed, system is functioning properly.

Radiator (Cooling) Fan Control Test (NX & Sentra 1.6L A/T Without A/C)

1. Start engine and warm to operating temperature. Ensure radiator fan operates at low speed during warm-up. If radiator fan does not operate at low speed, go to RADIATOR (COOLING) FAN LOW SPEED CONTROL TEST (NX & SENTRA - 1.6L A/T). If radiator fan operates at low speed, go to next step.
2. Turn ignition off. Disconnect radiator fan relay No. 1. Start engine and idle until engine temperature is above 221°F (105°C). Ensure radiator fan operates at high speed. If radiator fan does not operate at high speed, see RADIATOR (COOLING) FAN HIGH SPEED CONTROL TEST (NX & SENTRA - 1.6L A/T). If radiator fan operates at high speed, system is functioning properly.

Radiator (Cooling) Fan Low Speed Control Test (NX & Sentra 1.6L A/T)

1. Turn ignition off. Disconnect radiator fan relay No. 1. (Scheme 88)- (Scheme 90). Turn ignition on. Measure voltage between ground and radiator fan relay No. 2 harness connector terminals No. 2 (White/Green wire) and No. 5 (Black/White wire). (Scheme 83)and (Scheme 84). Battery voltage should be present. If battery voltage is present, go to step 3). If battery voltage is not present, go to next step.
2. Check 10-amp fuse located in fuse box under left instrument panel. Replace fuse as necessary. Check 30-amp fusible link located in fusible link and fuse box next to battery. Check Gray in-line fusible link near battery positive terminal. Replace fusible link(s) as necessary. If fuse and fusible links are okay, repair open in harness or connectors.
3. Turn ignition off. Disconnect radiator fan motor No. 1 and radiator fan motor No. 2 harness connectors. Check continuity between radiator fan motor No. 1 harness connector terminal "a" (Brown/White wire) and radiator fan relay No. 1 harness connector terminal No. 3 (Brown/White wire). Check continuity between radiator fan motor No. 2 harness connector terminal "a" (Brown/White wire) and radiator fan relay No. 1 harness connector terminal No. 3 (Brown/White wire). (Scheme 83)and (Scheme 84).
4. Check continuity between radiator fan motor No. 1 harness connector terminal "d" (Black wire) and ground. Check continuity between radiator fan motor No. 2 harness connector terminal "h" (Black wire) and ground. (Scheme 83)and (Scheme 84). Continuity should exist in all checks. If continuity exists in all checks, go to next step. If continuity does not exist in any check, repair open in appropriate wire or connector.
5. Disconnect ECM harness connector. ECM is located under center of instrument panel. Check continuity between ECM harness connector terminal No. 9 (Blue wire) and radiator fan relay No. 1 harness connector terminal No. 1 (Blue wire). see scheme 1, see scheme 2 and (Scheme 83) and (Scheme 84). Continuity should exist. If continuity exists, go to next step. If continuity does not exist, repair open in Blue wire or connectors between ECM and relay.
6. Check radiator fan relay No. 1. See «RELAYS»(ref-17400-S12256886262000122900000) under RELAYS & SOLENOIDS. Replace relay as necessary. If relay is okay, check fan motors. See RADIATOR FAN MOTOR TEST. Replace motor as necessary. If fan motor is okay, check ECM and ECM harness connector for damage, corrosion or improper connection. Repair as necessary.

Scheme 83

Scheme 84

Radiator (Cooling) Fan High Speed Control Test (NX & Sentra 1.6L A/T)

1. Turn ignition off. Disconnect radiator fan relay No. 2. (Scheme 88)- (Scheme 90). Turn ignition on. Measure voltage between ground and radiator fan relay No. 2 harness connector terminals No. 1 (White/Green wire) and No. 3 (Black/White wire). (Scheme 85)- (Scheme 87). Battery voltage should be present. If battery voltage is present, go to step 3). If battery voltage is not present, go to next step.
2. Check 10-amp fuse located in fuse box under left instrument panel. Replace fuse as necessary. Check 30-amp fusible link located in fusible link and fuse box next to battery. Check Gray in-line fusible link near battery positive terminal. Replace fusible link(s) as necessary. If fuse and fusible links are okay, repair open in harness or connectors.
3. Turn ignition off. Disconnect radiator fan motor No. 1 and radiator fan motor No. 2 harness connectors. Check continuity between radiator fan motor No. 1 harness connector terminal "b" (Brown wire) and radiator fan relay No. 2 harness connector terminal No. 5 (Brown wire). Check continuity between radiator fan motor No. 2 harness connector terminal "b" (Brown wire) and radiator fan relay No. 2 harness connector terminal No. 5 (Brown wire). (Scheme 85)- (Scheme 87).
4. Check continuity between radiator fan motor No. 1 harness connector terminal "c" (Red wire) and radiator fan relay No. 2 harness connector No. 6 (Red wire). Check continuity between radiator fan motor No. 2 harness connector terminal "c" (Red wire) and radiator fan relay No. 2 harness connector No. 6 (Red wire). Check continuity between radiator fan relay No. 2 harness connector terminal No. 7 (Black wire) and ground. (Scheme 85)- (Scheme 87). Continuity should exist in all checks. If continuity exists in all checks, go to next step. If continuity does not exist in any check, repair open in appropriate wire or connector.
5. Disconnect ECM harness connector. ECM is located under center of instrument panel. Check continuity between ECM harness connector terminal No. 10 (Blue/Black wire) and radiator fan relay No. 2 harness connector terminal No. 2 (Blue/Black wire). see scheme 1, see scheme 2 and (Scheme 85) - (Scheme 87). Continuity should exist. If continuity exists, go to next step. If continuity does not exist, repair open in Blue/Black wire or connectors between ECM and relay.
6. Check radiator fan relay No. 2. See «RELAYS»(ref-17400-S12256886262000122900000) under RELAYS & SOLENOIDS. Replace relay as necessary. If relay is okay, check fan motor(s). See RADIATOR FAN MOTOR TEST. Replace motor(s) as necessary. If fan motors are okay, check ECM and ECM harness connector for damage, corrosion or improper connection. Repair as necessary.

Scheme 85

Scheme 86

Scheme 87

Radiator (Cooling) Fan Control Test (NX & Sentra 1.6L M/T & 2.0L M/T)

1. For vehicles equipped with A/C, start engine and warm to operating temperature. Set temperature lever to full cold. Turn A/C switch on. Turn fan switch on. Run engine at idle with A/C on for several minutes. Ensure radiator fan operates. If radiator fan does not operate, turn A/C and fan switches off. Go to step 3). If radiator fan operates, system is functioning properly.
2. For vehicles without A/C, start engine. Keep engine speed at approximately 2000 RPM until engine is warmed up. Radiator fan should begin to operate during warm-up. If radiator fan does not operate, go to next step. If radiator fan operates, system is functioning properly.
3. Turn ignition off. Disconnect radiator fan relay No. 1. (Scheme 88)- (Scheme 90). Turn ignition on. Measure voltage between ground and radiator fan relay No. 1 harness connector terminals No. 2 (White/Green wire) and No. 5 (Black/White wire). (Scheme 88)- (Scheme 90). Battery voltage should be present. If battery voltage is present, go to step 5). If battery voltage is not present, go to next step.
4. Check 10-amp fuse located in fuse box under left instrument panel. Replace fuse as necessary. Check 30-amp fusible link located in fusible link and fuse box next to battery. Check Gray in-line fusible link near battery positive terminal. Replace fusible link(s) as necessary. If fuse and fusible links are okay, repair open in harness or connectors.
5. Turn ignition off. Disconnect radiator fan motor No. 1 and radiator fan motor No. 2 harness connectors. Check continuity between radiator fan motor No. 1 harness connector terminal "a" (Brown/White wire) and radiator fan relay No. 1 harness connector terminal No. 3 (Brown/White wire). Check continuity between radiator fan motor No. 2 harness connector terminal "a" (Brown/White wire) and radiator fan relay No. 1 harness connector terminal No. 3 (Brown/White wire). (Scheme 88)- (Scheme 90).
6. Check continuity between radiator fan motor No. 1 harness connector terminal "b" (Black wire) and ground. Check continuity between radiator fan motor No. 2 harness connector terminal "b" (Black wire) and ground. (Scheme 88)- (Scheme 90). Continuity should exist in all checks. If continuity exists in all checks, go to next step. If continuity does not exist in any check, repair open in appropriate wire or connector.
7. Disconnect ECM harness connector. ECM is located under center of instrument panel. Check continuity between ECM harness connector terminal No. 9 (Blue wire) and radiator fan relay No. 1 harness connector terminal No. 1 (Blue wire). see scheme 1, see scheme 2 and (Scheme 88) - (Scheme 90). Continuity should exist. If continuity exists, go to next step. If continuity does not exist, repair open in Blue wire or connectors between ECM and relay.
8. Check radiator fan relay No. 1. See «RELAYS»(ref-17400-S12256886262000122900000) under RELAYS & SOLENOIDS. Replace relay as necessary. If relay is okay, check fan motors. See CONDENSER FAN MOTOR TEST. Replace motor as necessary. If fan motor is okay, check ECM and ECM harness connector for damage, corrosion or improper connection. Repair as necessary.

Scheme 88

Scheme 89

Scheme 90

Radiator (Cooling) Fan Control Test (NX & Sentra 2.0L A/T With A/C)

1. Start engine and warm to operating temperature. Set temperature lever to full cold. Turn A/C switch on. Turn fan switch on. Run engine at idle with A/C on for several minutes. Ensure radiator fan operates at low speed. If radiator fan does not operate at low speed, go to RADIATOR (COOLING) FAN LOW SPEED CONTROL TEST (NX & SENTRA - 2.0L A/T). If radiator fan operates at low speed, go to next step.
2. Turn A/C and fan switches off. Turn ignition off. Disconnect engine coolant temperature sensor. Start engine and ensure radiator fan operates at a speed higher than low speed. If radiator fan does not operate as described, go to RADIATOR (COOLING) FAN HIGH SPEED CONTROL TEST (NX & SENTRA - 2.0L A/T). If radiator fan operates as described, system is functioning properly.

Radiator (Cooling) Fan Low Speed Control Test (NX & Sentra 2.0L A/T)

1. Turn ignition off. Disconnect radiator fan relay No. 1. (Scheme 88)- (Scheme 90). Turn ignition on. Measure voltage between ground and radiator fan relay No. 2 harness connector terminals No. 1 (White/Green wire), No. 3 (Black/White wire) and No. 6 (White/Black wire). (Scheme 91)- (Scheme 93). Battery voltage should be present. If battery voltage is present, go to step 3). If battery voltage is not present, go to next step.
2. Check 10-amp fuse located in fuse box under left instrument panel. Replace fuse as necessary. Check 30-amp fusible link located in fusible link and fuse box next to battery. Check Blue in-line fusible link near battery positive terminal. Replace fusible link(s) as necessary. If fuse and fusible links are okay, repair open in appropriate harness or connectors.
3. Turn ignition off. Disconnect radiator fan motor No. 1 and radiator fan motor No. 2 harness connectors. Check continuity between radiator fan motor No. 1 harness connector terminal "a" (Brown/White wire) and radiator fan relay No. 1 harness connector terminal No. 5 (Brown/White wire). Check continuity between radiator fan motor No. 2 harness connector terminal "e" (Brown wire) and radiator fan relay No. 1 harness connector terminal No. 7 (Brown wire). (Scheme 91)- (Scheme 93).
4. Check continuity between radiator fan motor No. 1 harness connector terminal "d" (Black wire) and ground. Check continuity between radiator fan motor No. 2 harness connector terminal "h" (Black wire) and ground. (Scheme 91)- (Scheme 93). Continuity should exist in all checks. If continuity exists in all checks, go to next step. If continuity does not exist in any check, repair open in appropriate wire or connector.
5. Disconnect ECM harness connector. ECM is located under center of instrument panel. Check continuity between ECM harness connector terminal No. 9 (Blue wire) and radiator fan relay No. 1 harness connector terminal No. 2 (Blue wire). see scheme 1, see scheme 2 and (Scheme 91) - (Scheme 93). Continuity should exist. If continuity exists, go to next step. If continuity does not exist, repair open in Blue wire or connectors between ECM and relay.
6. Check radiator fan relay No. 1. See «RELAYS»(ref-17400-S12256886262000122900000) under RELAYS & SOLENOIDS. Replace relay as necessary. If relay is okay, check fan motors. See RADIATOR FAN MOTOR TEST. Replace motor as necessary. If fan motor is okay, check ECM and ECM harness connector for damage, corrosion or improper connection. Repair as necessary.

Scheme 91

Scheme 92

Scheme 93

Radiator (Cooling) Fan High Speed Control Test (NX & Sentra 2.0L A/T)

1. Turn ignition off. Disconnect radiator fan relays No. 2 and No. 3. (Scheme 88)- (Scheme 93) Turn ignition on. Measure voltage between ground and radiator fan relays No. 2 and No. 3 harness connector terminals No. 1 (White/Green wire) and No. 3 (Black/White wire). (Scheme 85)- (Scheme 87). Battery voltage should be present. If battery voltage is present, go to step 3). If battery voltage is not present, go to next step.
2. Check 10-amp fuse located in fuse box under left instrument panel. Replace fuse as necessary. Check 30-amp fusible link located in fusible link and fuse box next to battery. Check Blue in-line fusible link near battery positive terminal. Replace fusible link(s) as necessary. If fuse and fusible links are okay, repair open in appropriate harness or connectors.
3. Turn ignition off. Disconnect radiator fan motor No. 1 and radiator fan motor No. 2 harness connectors. Check continuity between radiator fan motor No. 1 harness connector terminal "b" (Brown wire) and radiator fan relay No. 2 harness connector terminal No. 5 (Brown wire). Check continuity between radiator fan motor No. 1 harness connector terminal "c" (Red wire) and radiator fan relay No. 2 harness connector No. 7 (Red wire). Check continuity between radiator fan relay No. 2 harness connector terminal No. 6 (Black wire) and ground. (Scheme 94)and (Scheme 95).
4. Check continuity between radiator fan motor No. 2 harness connector terminal "f" (Brown/White wire) and radiator fan relay No. 3 harness connector terminal No. 5 (Brown/White wire). Check continuity between radiator fan motor No. 2 harness connector terminal "g" (Red wire) and radiator fan relay No. 3 harness connector No. 7 (Red wire). Check continuity between radiator fan relay No. 3 harness connector terminal No. 6 (Black wire) and ground. (Scheme 94)and (Scheme 95). Continuity should exist in all checks. If continuity exists in all checks, go to next step. If continuity does not exist in any check, repair open in appropriate wire or connector.
5. Disconnect ECM harness connector. ECM is located under center of instrument panel. Check continuity between ECM harness connector terminal No. 10 (Blue/Black wire) and radiator fan relays No. 2 and No. 3 harness connector terminal No. 2 (Blue/Black wire). see scheme 1, see scheme 2 and (Scheme 94) and (Scheme 95). Continuity should exist. If continuity exists, go to next step. If continuity does not exist, repair open in Blue/Black wire or connectors between ECM and relay(s).
6. Check radiator fan relays No. 2 and No. 3. See RELAYS under «RELAYS & SOLENOIDS»(ref-17400-S26910750242000122900000). Replace relay(s) as necessary. If relays are okay, check fan motor(s). See RADIATOR FAN MOTOR TEST. Replace motor(s) as necessary. If fan motors are okay, check ECM and ECM harness connector for damage, corrosion or improper connection. Repair as necessary.

Scheme 94

Scheme 95

Radiator (Cooling) Fan Control Test (Quest With A/C)

1. Start engine and warm to operating temperature. Set temperature lever to full cold. Turn A/C switch on. Turn fan switch on. Run engine at idle with A/C on for several minutes. Ensure radiator fan operates at low speed. If radiator fan does not operate at low speed, go to RADIATOR (COOLING) FAN LOW SPEED CONTROL TEST (QUEST). If radiator fan operates at low speed, go to next step.
2. Turn A/C and fan switches off. Turn ignition off. Disconnect radiator fan relays No. 1 and No. 2. (Scheme 96)and (Scheme 97). Start engine and idle until engine temperature is above 221°F (105°C). Ensure radiator fan operates at high speed. Reconnect radiator fan relay No. 2. Disconnect radiator fan relay No. 3. Start engine and idle until engine is above 221°F (105°C). Ensure radiator fan operates at high speed. If radiator fan does not operate at high speed in either test, see RADIATOR (COOLING) FAN HIGH SPEED CONTROL TEST (QUEST). If radiator fan operates at high speed, system is functioning properly.

Radiator (Cooling) Fan Control Test (Quest Without A/C)

1. Start engine and run at 2000 RPM until operating temperature is reached. Ensure radiator fan operates at low speed during warm-up. If radiator fan does not operate at low speed, go to RADIATOR (COOLING) FAN LOW SPEED CONTROL TEST (QUEST). If radiator fan operates at low speed, go to next step.
2. Turn A/C and fan switches off. Turn ignition off. Disconnect radiator fan relays No. 1 and No. 2. (Scheme 96)and (Scheme 97). Start engine and idle until engine temperature is above 221°F (105°C). Ensure radiator fan operates at high speed. Reconnect radiator fan relay No. 2. Disconnect radiator fan relay No. 3. Start engine and idle until engine is above 221°F (105°C). Ensure radiator fan operates at high speed. If radiator fan does not operate at high speed in either test, see RADIATOR (COOLING) FAN HIGH SPEED CONTROL TEST (QUEST). If radiator fan operates at high speed, system is functioning properly.

Radiator (Cooling) Fan Low Speed Control Test (Quest)

1. Turn ignition off. Disconnect radiator fan relay No. 1. (Scheme 96)and (Scheme 97). Turn ignition on. Measure voltage between ground and radiator fan relay No. 1 harness connector terminals No. 2 (Blue wire) and No. 3 (Blue/Yellow wire). (Scheme 96)and (Scheme 97). Battery voltage should be present. If battery voltage is present, go to step 3). If battery voltage is not present, go to next step.
2. Check 10-amp fuse located in fuse box under left instrument panel. Replace fuse as necessary. Check 120-amp and 65-amp fusible link located in fusible link and fuse box next to battery. Replace fusible link(s) as necessary. If fuse and fusible links are okay, repair open in appropriate harness or connectors.
3. Turn ignition off. Disconnect radiator fan motor harness connectors. Check continuity between radiator fan motor harness connector terminal "b" (Blue/White wire) and radiator fan relay No. 1 harness connector terminal No. 5 (Blue/White wire). Check continuity between radiator fan motor harness connector terminal "c" (Black wire) and ground. (Scheme 96)and (Scheme 97). Continuity should exist in all checks. If continuity exists in all checks, go to next step. If continuity does not exist in any check, repair open in appropriate wire or connector.
4. Disconnect ECM harness connector. ECM is located behind glove box. Check continuity between ECM harness connector terminal No. 9 (Blue/Orange wire) and radiator fan relay No. 1 harness connector terminal No. 1 (Blue/Orange wire). see scheme 1, see scheme 2 and (Scheme 96) and (Scheme 97). Continuity should exist. If continuity exists, go to next step. If continuity does not exist, repair open in Blue/Orange wire or connectors between ECM and relay.
5. Check radiator fan relay No. 1. See RELAYS under «RELAYS & SOLENOIDS»(ref-17400-S26910750242000122900000). Replace relay as necessary. If relay is okay, check fan motors. See RADIATOR FAN MOTOR TEST. Replace motor as necessary. If fan motor is okay, check ECM and ECM harness connector for damage, corrosion or improper connection. Repair as necessary.

Scheme 96

Scheme 97

Radiator (Cooling) Fan High Speed Control Test (Quest)

1. Turn ignition off. Disconnect radiator fan relay No. 2. (Scheme 96)and (Scheme 97). Turn ignition on. Measure voltage between ground and radiator fan relay No. 2 harness connector terminals No. 2 (Blue wire) and No. 3 (Blue/Yellow wire). (Scheme 98) Battery voltage should be present. If battery voltage is present, go to step 3). If battery voltage is not present, go to next step.
2. Check 10-amp fuse located in fuse box under left instrument panel. Replace fuse as necessary. Check 120-amp and 65-amp fusible link located in fusible link and fuse box next to battery. Replace fusible link(s) as necessary. If fuse and fusible links are okay, repair open in appropriate harness or connectors.
3. Turn ignition off. Disconnect radiator fan relay No. 3. (Scheme 98) Check continuity between radiator fan relay No. 2 harness connector terminals No. 2 (Blue wire) and radiator fan relay No. 3 harness connector terminals No. 2 (Blue wire). Check continuity between radiator fan relay No. 2 harness connector terminals No. 3 (Blue/Yellow wire) and radiator fan relay No. 3 harness connector terminals No. 3 (Blue/Yellow wire). Continuity should exist in all checks. If continuity exists in all checks, go to next step. If continuity does not exist in any check, repair open in appropriate wire or connector.
4. Disconnect radiator fan motor harness connector. Check continuity between radiator fan motor harness connector terminal "a" (Blue/Red wire) and radiator fan relay No. 2 harness connector terminal No. 5 (Blue/Red wire). Check continuity between radiator fan motor harness connector terminal "c" (Black wire) and ground. (Scheme 96)and (Scheme 97). Continuity should exist. If continuity exists, go to next step. If continuity does not exist, repair open in appropriate wire or connector.
5. Check continuity between radiator fan relay No. 2 harness connector terminal No. 5 (Blue/Red wire) and radiator fan relay No. 3 harness connector terminal No. 5 (Blue/Red wire). (Scheme 98) Continuity should exist. If continuity exists, go to next step. If continuity does not exist, repair open in Blue/Red wire or connectors.
6. Disconnect ECM harness connector. ECM is located behind glove box. Check continuity between ECM harness connector terminal No. 10 (Brown/White wire) and radiator fan relay No. 2 harness connector terminal No. 1 (Brown/White wire). see scheme 1, see scheme 2 and (Scheme 98). Continuity should exist. If continuity exists, go to next step. If continuity does not exist, repair open in Brown/White wire or connectors between ECM and relay.
7. Check continuity between radiator fan relay No. 2 harness connector terminal No. 1 (Brown/White wire) and radiator fan relay No. 3 harness connector terminal No. 1 (Brown/White wire). (Scheme 98) Continuity should exist. If continuity exists, go to next step. If continuity does not exist, repair open in Brown/White wire or connectors.
8. Check radiator fan relays No. 2 and No. 3. See RELAYS under «RELAYS & SOLENOIDS»(ref-17400-S26910750242000122900000). Replace relay(s) as necessary. If relays are okay, check fan motor(s). See RADIATOR FAN MOTOR TEST. Replace motor(s) as necessary. If fan motors are okay, check ECM and ECM harness connector for damage, corrosion or improper connection. Repair as necessary.

Scheme 98

Radiator (Cooling) Fan Control Test (300ZX)

1. Turn ignition off. Disconnect radiator fan relay. Turn ignition on. Measure voltage between radiator fan relay terminals "b" (Purple wire) and "d" (Green/White wire). (Scheme 99)and (Scheme 100). Battery voltage should be present. If battery voltage is present, go to step 4). If battery voltage is not present, go to next step.
2. Check Green, Red and Blue fusible links located in fusible link box next to battery. Replace fusible link(s) as necessary. Check 10-amp fuse located in relay box at left front corner of engine compartment. Replace fuse as necessary. If fusible links and 10-amp fuse are okay, disconnect battery (B +) connector (White wire). Check harness continuity between B + terminal at battery and fan relay harness connector terminal "b". (Scheme 99)and (Scheme 100).
3. Check harness continuity between B + terminal at battery and ignition switch. Check harness continuity between ignition switch and radiator fan relay harness connector terminal "d". (Scheme 99)and (Scheme 100). Continuity should exist in all checks. If continuity exists in all checks, go to next step. If continuity does not exist in any check, repair open in appropriate wire or connector.
4. Install jumper wire between radiator fan relay harness connector terminals "a" and "b". (Scheme 99)and (Scheme 100). Radiator fan motor should operate. If radiator fan motor does not operate, repair open in Green wire between fan motor and relay harness connector "a". If Green wire is okay, remove jumper wire. Disconnect radiator fan motor connector. Apply battery voltage across fan motor connector terminals. If fan motor does not operate, replace motor. If fan motor operates, check radiator fan relay. See RELAYS under «RELAYS & SOLENOIDS»(ref-17400-S26910750242000122900000). Replace relay as necessary.

Scheme 99

Scheme 100

Radiator Fan Motor Test

Disconnect fan motor harness connector(s). Apply battery across fan motor terminals and observe motor operation. (Scheme 101) See FAN MOTOR OPERATION TEST table. If motor does not operate as indicated, replace motor.

FAN MOTOR OPERATION TEST

Scheme 101