P0400
DTC P0400 EXHAUST GAS RECIRCULATION FLOW1. OUTLINE OF DIAGNOSIS
Detect the malfunction of EGR system. Intake manifold pressure (negative pressure) is stable because the throttle valve is fully closed during the fuel shutoff in deceleration. In this case, the intake manifold pressure changes when EGR valve is opened or closed. Judge EGR system is OK or NG according to intake manifold pressure change amount.
2. COMPONENT DESCRIPTION
3. ENABLE CONDITION
4. GENERAL DRIVING CYCLE
Perform the diagnosis only once at the fuel shutoff in deceleration in vehicle speed more than 53 km/h (approx. 33 MPH). Pay attention to vehicle speed and engine speed. (The diagnosis is not completed if vehicle speed and engine speed are out of condition due to deceleration.)
5. DIAGNOSTIC METHOD
Measure the pressure in the following procedures when the enable conditions are completed, and then diagnosis by calculating the result.
1. PMOF1 is equal to the intake manifold pressure at enable condition completed, and EGR target step is set to 50 steps (almost fully opened)
2. PMON is equal to the intake manifold pressure in 1 second after EGR target step is set 50 steps (when enable conditions are completed), and EGR target step is set to 0 step.
3. PMOF2 is equal to the intake manifold pressure in 1 second after EGR target step is set to 0 step (in 2 seconds after enable conditions are completed).
- Abnormality Judgment
Judge NG when the malfunction criteria below is completed. Judge OK when not completed. PMON -(PMOF1 + PMOF2)/2 < 2.48 kPa (18.63 mmHg, 0.733 inHg) Time Needed for Diagnosis:Once
Malfunction Indicator Light Illumination:Illuminates when malfunction occurs in 2 continuous driving cycles.
6. DTC CLEAR CONDITION
- When the OK idling cycle was completed 40 times in a row
- When "Clear Memory" was performed
7. MALFUNCTION INDICATOR LIGHT CLEAR CONDITION
- When the OK driving cycle was completed 3 times in a row
- When "Clear Memory" was performed
8. FAIL SAFE
A/F main learning: Not allowed
Knock learning: Not allowed
EGR control: Not allowed to operate
9. ECM OPERATION AT DTC SETTING
- Memorize the freeze frame data. (For test mode $02)
- Memorize the diagnosis value and trouble standard value. (For test mode $06)