DTC P0402 [LF, L3]

id0102008205a3

DTC P0402

EGR flow excessive detected

DETECTION CONDITION

• The PCM monitors difference in intake manifold pressures when EGR is operated and when it is stopped. If the difference is too large, the PCM determines that the EGR flow is excessive.
Diagnostic support note
• This is an intermittent monitor (EGR).
• The MIL illuminates if the PCM detects the above malfunction conditions in two consecutive drive cycles.
• The PENDING CODE is available if the PCM detects the above malfunction condition during the first drive cycle.
• The FREEZE FRAME DATA is available.
• The DTC is stored in the PCM memory.

POSSIBLE CAUSE

• EGR valve gasket is not installed.
• EGR valve gasket has been damaged.
• PCM malfunction

Diagnostic procedure

STEP

INSPECTION

ACTION

1
VERIFY FREEZE FRAME DATA HAS BEEN RECORDED
• Has the FREEZE FRAME DATA been recorded?
Yes
Go to the next step.
No
Record the FREEZE FRAME DATA on repair order, then go to the next step.
2
VERIFY RELATED SERVICE INFORMATION AVAILABILITY
• Check for related Service Information availability.
• Is any related Service Information available?
Yes
Perform repair or diagnosis according to available Service Information.
• If the vehicle is not repaired, go to the next step.
No
Go to the next step.
3
INSPECT FOR OTHER DTCS
• Turn the ignition switch to the OFF position then ON (Engine off).
• Have other DTCs been stored?
Yes
Repair the circuit malfunction for applicable DTCs.
No
Go to the next step.
4
INSPECT EGR VALVE GASKET HAS INSTALLED
• Turn the ignition switch to the OFF position.
• Remove the EGR valve.
• Is the EGR valve gasket installed?
Yes
Go to the next step.
No
Install the EGR valve gasket, then go to Step 6.
5
INSPECT EGR VALVE GASKET MALFUNCTION
• Does the EGR valve gasket have any cracks or damage?
Yes
Replace the EGR valve gasket, then go to Step 6.
No
Go to the next step.
6
MONITOR EGR SYSTEM BY DRIVE MODE
• Clear the DTC from the PCM memory using the WDS or equivalent.
• Run the PCM adaptive memory procedure drive mode.
• Access the RFC FLAG PID using the WDS or equivalent.
• Is the RFC FLAG PID OFF?
Yes
Retry this step.
No
Go to the next step.
7
MONITOR EGR SYSTEM BY DRIVE MODE
• Run the HO2S heater, HO2S, and EGR system repair verification drive mode.
• Verify that the EGR system monitor has done the check using On-Board Readiness Test function.
• Has the EGR system been monitored?
Yes
Go to the next step.
No
Retry this step.
8
VERIFY TROUBLESHOOTING OF DTC P0402 COMPLETED
• Make sure to reconnect all disconnected connectors.
• Access the DIAGNOSTIC MONITORING TEST RESULTS.
• Verify the TEST ID 10: 31: 83 value.
• Is the value within specification?
Yes
Go to the next step.
No
Replace the PCM, then go to the next step.
9
VERIFY AFTER REPAIR PROCEDURE
• Perform the "After Repair Procedure".
• Are any DTCs present?
Yes
Go to the applicable DTC inspection.
No
Troubleshooting completed.