P0400
TECHNICAL DESCRIPTION- When the EGR solenoid switches from "OFF" to "ON" while the engine is running, EGR gas flows.
- The ECM
DTC SET CONDITIONS
Check Conditions
- At least twenty seconds have passed since the last monitor was complete.
- Engine coolant temperature is higher than 77°C (141 °F).
- Engine speed is at between 1,000 and 1,650
- Intake air temperature is higher than 5°C (41°F).
- Barometric pressure is higher than 76 kPa (11 psi).
- Vehicle speed is 5 km/h (3.1 mph)
- At least ninety seconds have passed since manifold differential pressure sensor output voltage fluctuated 1.5 volts or more.
- The throttle valve is closed.
- Volumetric efficiency is lower than 18
- Monitoring time: 2 seconds.
Judgement Criteria
- The intake manifold pressure fluctuations are minimal. When the EGR solenoid is turned ON.
- Three monitors during one drive cycle
TROUBLESHOOTING HINTS
The most likely causes for this code to be set are:
- EGR valve does not open.
- EGR control vacuum is too low.
- EGR solenoid failed.
- Open or shorted EGR solenoid circuit, or loose connector.
- Manifold differential pressure sensor failed.
- ECM failed.
- PCM failed.
TECHNICAL DESCRIPTION
- When the EGR solenoid switches from "OFF" to "ON" while the engine is running, EGR gas flows.
- The ECM
DTC SET CONDITIONS
Check Conditions
- At least twenty seconds have passed since the last monitor was complete.
- Engine coolant temperature is higher than 77°C (141 °F).
- Engine speed is at between 1,000 and 1,650
- Intake air temperature is higher than 5°C (41 °F).
- Barometric pressure is higher than 76 kPa (11 psi).
- Vehicle speed is 5 km/h (3.1 mph)
- At least ninety seconds have passed since manifold differential pressure sensor output voltage fluctuated 1.5 volts or more.
- The throttle valve is closed.
- Volumetric efficiency is lower than 18
- Monitoring time: 2 seconds.
Judgement Criteria
- The intake manifold pressure fluctuations are minimal. When the EGR solenoid is turned ON.
- Three monitors during one drive cycle
TROUBLESHOOTING HINTS
The most likely causes for this code to be set are:
- EGR valve does not open.
- EGR control vacuum is too low.
- EGR solenoid failed.
- Open or shorted EGR solenoid circuit, or loose connector.
- Manifold differential pressure sensor failed.
- ECM failed.
- PCM failed.
DIAGNOSIS
Required Special Tool:
MB991502: Scan Tool (MUT-II)
STEP 1. Check the EGR system
Refer to Emission Control System - Exhaust Gas Recirculation (EGR) System.
If correct, go to Step 2.
If incorrect, repair or replace. Then go to Step 3.
CAUTION: To prevent damage to scan tool MB991502, always turn the ignition switch to "LOCK" (OFF) position before connecting or disconnecting scan tool MB991502.
STEP 2. Using scan tool MB991502, actuator test item 95: Manifold Differential Pressure Sensor.
1. Connect scan tool MB991502 to the data link connector.
2. Start the engine and run at idle.
3. Set scan tool MB991502 to the data reading mode for item 95, Manifold Differential Pressure Sensor.
- Should be between 22.6 and 36.0 kPa at engine idling.
If not within specifications, refer to DTC P1400 - Manifold Differential Pressure Sensor Circuit Malfunction.
If within specifications, clean the EGR valve and EGR passage. Then go to Step 3.
STEP 3. Test the OBD-II drive cycle.
1. Carry out a test drive with the drive cycle pattern. Refer to Procedure 5 - Exhaust Gas Recirculation (EGR) System Monitor.
2. Read the diagnostic trouble code, and confirm that a diagnostic trouble code P0400 does not reset.