DTC P0401 [AJ] (VIN: JMZ LW19J7*# 300001-, JM0 LW10J300 300001-301405, JM6 LW10J300 300001-, JM8 LW28J**# 300001-301513)

BME010200400201

Australian, General (L.H.D. R.H.D.) Specs.

DTC P0401

EGR flow insufficient detected

DETECTION CONDITION

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

POSSIBLE CAUSE

• EGR valve malfunction
• EGR boost sensor malfunction
• EGR boost sensor solenoid valve malfunction
• EGR gasket malfunction
• PCM malfunction

Diagnostic procedure

STEP

INSPECTION

ACTION

1
VERIFY FREEZE FRAME DATA HAS BEEN RECORDED
• Has FREEZE FRAME DATA been recorded?
Yes
Go to the next step.
No
Record 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 vehicle is not repaired, go to the next step.
No
Go to the next step.
3
INSPECT FOR OTHER DTCS
• Turn the ignition switch off, then to the ON position (Engine off).
• Have other DTCs been stored?
Yes
Repair circuit malfunction for applicable DTCs.
No
Go to the next step.
4
INSPECT VACUUM HOSE CONDITION
• Inspect vacuum hoses for clogs, any damages, frozen, or vacuum leakage.
• Is there any malfunction?
Yes
Replace vacuum hoses, then go to Step 9.
No
Go to the next step.
5
INSPECT EGR VALVE MALFUNCTION
• Perform EGR valve inspection.
• Is the EGR valve normal?
Yes
Go to the next step.
No
Replace the EGR valve, then go to Step 9.
6
INSPECT EGR BOOST SENSOR MALFUNCTION
• Perform EGR boost sensor inspection.
• Is the EGR boost sensor normal?
Yes
Go to the next step.
No
Replace the EGR boost sensor, then go to Step 9.
7
INSPECT EGR BOOST SENSOR SOLENOID VALVE
• Perform the EGR boost sensor solenoid valve inspection.
• Is the EGR boost sensor solenoid valve normal?
Yes
Go to the next step.
No
Replace the EGR boost sensor solenoid valve, then go to Step 9.
8
INSPECT EGR VALVE PASSAGE
• Turn the ignition switch off.
• Remove the EGR valve.
• Is gasket installation normal?
Yes
Go to the next step.
No
Install gasket correctly, then go to Step 9.
9
MONITOR EGR SYSTEM BY DRIVE MODE
• Clear the DTC from the PCM memory using the WDS or equivalent.
• Run PCM adaptive memory procedure drive mode.
• Access RFC FLAG PID using WDS or equivalent.
• Is RFC FLAG PID OFF?
Yes
Retry this step.
No
Go to the next step.
10
MONITOR EGR SYSTEM BY DRIVE MODE
• Run HO2S heater, HO2S, and EGR system repair verification drive mode.
• Check EGR System Monitor is checked using On-Board Readiness Test function.
• Has EGR system been monitored?
Yes
Go to the next step.
No
Retry this step.
11
VERIFY TROUBLESHOOTING OF DTC P0401 COMPLETED
• Make sure to reconnect all disconnected connectors.
• Access DIAGNOSTIC MONITORING TEST RESULTS.
• Verify TEST ID 10: 41: 00 value.
• Is value within specification?
Yes
Go to the next step.
No
Replace the PCM, then go to the next step.
12
VERIFY AFTER REPAIR PROCEDURE
• Perform "After Repair Procedure".
• Is there any DTC present?
Yes
Go to the applicable DTC inspection.
No
Troubleshooting completed.