DTC P0400: EGR Function: Procedure
- Check exhaust system for leaks. If problem exists, repair as necessary and retest system. If problem does not exist, go to next step.
- Turn ignition off. Disconnect EGR Volume Control Valve (EGR-VCV) harness connector. See Fig 1. Turn ignition on. Measure voltage between ground and EGR-VCV harness connector terminals No. 2 and 5 (both Green/White wires). See Fig 2. If battery voltage exists, go to next step. If battery voltage does not exist, repair open or short circuit and retest system. See WIRING DIAGRAMS article.
- Turn ignition off. Disconnect ECM harness connector. See Figure. Check continuity of the following:
- Light Blue wire between EGR-VCV harness connector terminal No. 1 and ECM harness connector terminal No. 8.
- Red/Yellow wire between EGR-VCV harness connector terminal No. 3 and ECM harness connector terminal No. 17.
- White/Black wire between EGR-VCV harness connector terminal No. 4 and ECM harness connector terminal No. 9.
- Yellow wire between EGR-VCV harness connector terminal No. 6 and ECM harness connector terminal No. 18.
See Figure. Also check circuits for short to ground and short to voltage. Repair circuit(s) as necessary and retest system. If circuits are okay, go to next step.
- Check EGR passages and hose for blockage and damage. If problem exists, repair as necessary and retest system. If problem does not exist, go to next step.
- Turn ignition off. Remove EGR temperature sensor, and place in heated water. See Fig 3. Measure resistance between EGR temperature sensor terminals, with water at specified temperatures. See EGR TEMPERATURE SENSOR RESISTANCE table. If resistance is as specified, go to next step. If resistance is not as specified, replace EGR temperature sensor and retest system.
- Measure resistance between EGR-VCV terminal No. 2 and terminals No. 1 and 3, and between terminal No. 5 and terminals No. 4 and 6. See Fig 4. Resistance should be 20.9-23.1 ohms at 68°F (20°C). If resistance is as specified, go to next step. If resistance is not as specified, replace and EGR volume control valve and retest system.
- Remove EGR-VCV. Connect EGR-VCV and ECM harness connectors. Turn ignition on, then off while observing EGR-VCV shaft. If shaft moves forward and backwards in relation to ignition switch position, go to next step. If shaft does not move forward and backwards in relation to ignition switch position, replace EGR-VCV and retest system.
- No problem is indicated at this time. Problem may be intermittent. See INTERMITTENTS in TROUBLE SHOOTING - NO CODES article.
EGR TEMPERATURE SENSOR RESISTANCE
| Temperature - °F (°C) | K/Ohms |
|---|---|
| 32 (0) | 620-1050 |
| 122 (50) | 65-94 |
| 212 (100) | 11-15 |