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

CONSULT TESTER

In addition to self-diagnostic capability, all models are equipped with a diagnostic connector for use with Nissan Consult Tester (J-38465). Connector is located on driver's side of center console (above accelerator pedal).

Note. When performing basic diagnostic procedures, be careful not to erase any diagnostic information stored in ECM memory.

HARD FAILURES

Hard failures cause CHECK ENGINE light (if equipped) to illuminate and remain on until problem is repaired. If light comes on and remains on (light may flash) during vehicle operation, cause of malfunction must be determined using diagnostic (code) charts. If a sensor fails, ECM will use a substitute value in its calculations to continue engine operation. In this condition (fail-safe mode), the vehicle runs but driveability will not be optimum and engine speed is restricted (2000-3000 RPM depending on model).

INTERMITTENT FAILURES

Intermittent failures may cause CHECK ENGINE light to flicker or illuminate and go out after intermittent fault goes away. However, corresponding trouble code will be retained in ECM memory. If related fault does not reoccur within 50 ignition cycles, related trouble code will be erased from ECM memory. Intermittent failures may be caused by sensor, connector or wiring problems. See INTERMITTENTS in TESTS W/O CODES article in the ENGINE PERFORMANCE section.

Note. Follow diagnostic routine when testing engine control systems. See DIAGNOSTIC ROUTINE table for correct order of procedure.

DIAGNOSTIC ROUTINE

MIL (CHECK ENGINE LIGHT)

All models are equipped with a MIL (CHECK ENGINE light). As a bulb check, light will illuminate when ignition is on and engine is not running. MIL will also illuminate when an engine control system fault has been detected. Not all trouble codes activate MIL.

Mode I (Bulb Check)

Engine is not running in this mode. Turn ignition switch to ON position. MIL (CHECK ENGINE light) should illuminate. If light does not illuminate, check and replace bulb as necessary.

Mode I (Malfunction Warning)

This is normal vehicle operating mode and engine must be running. If a malfunction occurs, MIL (CHECK ENGINE light) will illuminate, indicating an engine control system malfunction has occurred and a code has been stored.

Mode II (Oxygen Sensor Monitor)

In Mode II (engine running), MIL (CHECK ENGINE light) is used to monitor air/fuel mixture feedback control. Vehicle must be in closed loop for Mode II results to be valid.

In closed loop, MIL indicates if system is running rich (light off), lean (light on) or at ideal air/fuel ratio (blinking MIL).

RETRIEVING CODES

Note. Not all trouble codes will activate MIL (CHECK ENGINE light).

When Mode II is accessed (engine not running), codes stored in ECM memory will be flashed by MIL (CHECK ENGINE light). Long flashes (.6 second) indicate first digit of code. Short flashes (.3 second) indicate second digit of code. For example: 3 long flashes followed by 5 short flashes of MIL indicate a Code 35.

CLEARING CODES

Note. Ensure all diagnostic codes are retrieved from ECM memory before disconnecting battery or erasing stored memory.

Memory Erase

Stored memory will be erased if battery is disconnected or diagnostic mode is switched from Mode II to Mode I (modes cannot be switched with engine running). To switch from Mode II to Mode I while in Mode II, with ignition switch in ON position and engine not running, connect a jumper wire between harness connector terminals "A" (Gray/Blue wire) and "B" (Blue/White wire), wait at least two seconds, and remove. System is now in Mode I. Reconnect harness connectors. (Схема №1)

Final Check For All CIRCUIT TESTS

Unless otherwise instructed in code inspection, perform following final check after each repair is completed.

1. Erase diagnostic test Mode II (self-diagnostic results) memory. See CLEARING CODES under SELF-DIAGNOSTIC SYSTEM.
2. Ensure Code 55 (no malfunction) is displayed in self -diagnostic mode.
3. Perform a test drive.
4. Perform diagnostic test Mode II (self-diagnostic results) again.

If results are okay, inspection is complete. If results are not okay, ensure ECM pin terminals and ECM harness connector are not damaged.

SUMMARY

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