SELF-DIAGNOSTIC SYSTEM
Self-diagnostic system is used for diagnosing malfunctions of Electronic Concentrated Control System (ECCS) sensors and actuators. Electronic Control Unit (ECU) has 2 available diagnostic modes. Before entering self-diagnostics, perform BASIC DIAGNOSTIC PROCEDURES. This prevents wasted diagnostic time and invalid diagnostic results.
Note. When performing BASIC DIAGNOSTIC PROCEDURES, DO NOT erase any diagnostic information stored in ECU memory.
DIAGNOSTIC MODES
Self-diagnostic system can detect ECCS malfunctions and store related trouble codes. Intermittent codes are also stored. All codes are stored until cleared from memory. If an intermittent does not reoccur within 50 ignition key cycles, it will be cleared from memory.
Switching modes is not possible when engine is running. During diagnosis, self-diagnostic system will automatically return to Mode I from Mode II when ignition is turned off.
ENTERING SELF-DIAGNOSTICS
- Turn ignition on, but leave engine off. Using a small screwdriver, turn diagnostic mode selector on ECU fully clockwise. Wait at least 2 seconds, and then turn diagnostic mode selector fully counterclockwise. Mode II self-diagnostics will result and CHECK ENGINE light and Red LED inspection light will flash codes (if present).
- If engine is started at this stage, CHECK ENGINE light and Red LED inspection light will display condition of air/fuel mixture, monitored by O2 sensor, whether system is in closed or open loop.
Note. Turn back diagnostic mode selector to fully counterclockwise position whenever vehicle is in use. Switching modes is not possible when engine is running.
DIAGNOSTIC TROUBLE CODE DEFINITION
Note. When using trouble code charts (Scheme 10)for symbol identification.
| Code | System Affected | Probable Cause |
|---|---|---|
| 11 (1) | Crank Angle Sensor | (2) No Crank Signal |
| 12 | Airflow Meter Circuit | Open/Shorted Circuit |
| 13 | Coolant Temperature Sensor | Open/Shorted Circuit |
| 14 | Vehicle Speed Sensor (VSS) | No VSS Signal |
| 16 | Traction Control System | (3) No TCS Signal |
| 21 (1) | Ignition Signal Circuit | (2) Open/Shorted Circuit |
| 31 | ECU | Signals Not Normal |
| 32 (4) | EGR Function | No EGR Action |
| 33 | O2 Sensor (Left) | Open Circuit/High O2 Signal |
| 34 (1) | Knock Sensor | Open/Shorted Circuit |
| 35 (4) | Exhaust Temperature Sensor | Open/Shorted Circuit |
| 43 | Throttle Sensor | Open/Shorted Circuit |
| 45 (4) | Injector Leak | Leak At Injectors |
| 46 (4) (W/TCS) | Secondary Throttle Position Sensor | Open/Shorted Circuit |
| 51 (4) | Injector Circuit | Injector Does Not Work |
| 53 | O2 Sensor (Right) | Open Circuit/High O2 Signal |
| 54 (1) | Automatic Transmission Signal | Open Signal Transmission Control Unit |
| 55 (1) | No Malfunction (Q45) | Normal Condition |
| (1) Trouble code will not activate CHECK ENGINE light. (2) If Codes 11 and 21 are present at same time, check items causing a malfunction of crank angle sensor circuit first. (3) See ANTI-LOCK BRAKE SYSTEM article in the BRAKES Section. (4) California models. | ||
| (1) | Trouble code will not activate CHECK ENGINE light. |
| (2) | If Codes 11 and 21 are present at same time, check items causing a malfunction of crank angle sensor circuit first. |
| (3) | See ANTI-LOCK BRAKE SYSTEM article in the BRAKES Section. |
| (4) | California models. |
DIAGNOSTIC TROUBLE CODE IDENTIFICATION CHART
Scheme 10
TROUBLE CODE CHARTS
Note. Most code charts shown include procedures using Nissan Consult Tester (J-38465). If consult tester is not available, disregard steps using consult tester and use alternate test procedure. OK = Okay; NG = No Good.
