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DTC P0403 [L3 Turbo]

id0102b7807100

DTC P0403 | EGR valve (stepper motor) circuit malfunction
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DETECTION CONDITION | • PCM monitors the input voltage from the EGR valve. If the voltage remain low or high, the PCM determines that the EGR valve circuit has a malfunction. Diagnostic support note • This is a continuous monitor. (CCM) • MIL illuminates if the PCM detects above malfunction condition in two consecutive drive cycles or in one drive cycle while the DTC for the same malfunction has been stored in the PCM. • PENDING CODE is available if the PCM detects the above malfunction condition during first drive cycle. • FREEZE FRAME DATA is not available. • DTCs are not stored in the PCM memory.
POSSIBLE CAUSE | • EGR valve malfunction • Connector or terminal malfunction • Short to the power supply in the wiring harness between EGR valve terminal E and PCM terminal 4D • Short to the power supply in the wiring harness between EGR valve terminal A and PCM terminal 4G • Short to the power supply in the wiring harness between EGR valve terminal B and PCM terminal 4J • Short to the power supply in the wiring harness between EGR valve terminal F and PCM terminal 4M • Short to ground circuit in wiring harness between EGR valve terminal E and PCM terminal 4D • Short to ground circuit in wiring harness between EGR valve terminal A and PCM terminal 4G • Short to ground circuit in wiring harness between EGR valve terminal B and PCM terminal 4J • Short to ground circuit in wiring harness between EGR valve terminal F and PCM terminal 4M • Open circuit in the wiring harness between EGR valve terminal E and PCM terminal 4D • Open circuit in the wiring harness between EGR valve terminal A and PCM terminal 4G • Open circuit in the wiring harness between EGR valve terminal B and PCM terminal 4J • Open circuit in the wiring harness between EGR valve terminal F and PCM terminal 4M • Open circuit in the wiring harness between main relay terminal C and EGR valve terminal C • Open circuit in the wiring harness between main relay terminal C and EGR valve terminal D • PCM malfunction

Diagnostic procedure

STEP | INSPECTION | ACTION
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1 | VERIFY FREEZE FRAME DATA AND DIAGNOSTIC MONITORING TEST RESULTS HAS BEEN RECORDED • Has FREEZE FRAME DATA been recorded? | Yes | Go to the next step.
No | Record the FREEZE FRAME DATA on the repair order, then go to the next step.
2 | VERIFY RELATED REPAIR INFORMATION AVAILABILITY • Verify related Service Information availability. • Is any related Service Information available? | Yes | Perform repair or diagnosis according to the available Service information. If the vehicle is not repaired, go to the next step.
No | Go to the next step.
3 | INSPECT EGR VALVE CONNECTOR FOR POOR CONNECTION • Turn the ignition switch off. • Disconnect the EGR valve connector. • Inspect for poor connection (such as damaged/pulled-out pins, corrosion). • Is there any malfunction? | Yes | Repair or replace the terminals and/or connector, then go to Step 10.
No | Go to the next step.
4 | INSPECT POWER CIRCUIT FOR OPEN CIRCUIT • Turn ignition switch to the ON position (Engine off). • Measure the voltage following the terminal and body ground. - EGR valve terminal C (harness-side) - EGR valve terminal D (harness-side) • Is voltage B+? | Yes | Go to the next step.
No | Repair or replace the wiring harness for an open circuit then go to Step 10.
5 | INSPECT EGR VALVE • Perform the EGR valve inspection. (See EGR VALVE INSPECTION [L3 Turbo].) • Is the EGR valve normal? | Yes | Go to the next step.
No | Replace the EGR valve, then go to Step 10.
6 | INSPECT FOR CONTROL CIRCUIT FOR SHORT TO GROUND • Turn the ignition switch off. • Inspect for continuity between the following terminals and body ground: - EGR valve terminal E (harness-side) - EGR valve terminal A (harness-side) - EGR valve terminal B (harness-side) - EGR valve terminal F (harness-side) • is there continuity? | Yes | Repair or replace the wiring harness for a short to ground, then go to Step 10.
No | Go to the next step.
7 | INSPECT FOR CONTROL CIRCUIT FOR SHORT TO POWER SUPPLY • Turn the ignition switch to the ON position (Engine off). • Measure the voltage between the following terminals and body ground: - EGR valve terminal E (harness-side) - EGR valve terminal A (harness-side) - EGR valve terminal B (harness-side) - EGR valve terminal F (harness-side) • Is voltage B+? | Yes | Repair or replace wiring harness for a short to power supply, then go to Step 10.
No | Go to the next step.
8 | INSPECT PCM CONNECTOR FOR POOR CONNECTION • Turn the ignition switch off. • Disconnect PCM connector. • Inspect for poor connection (such as damaged/pulled-out pins, corrosion). • Is there any malfunction? | Yes | Repair or replace the terminals and/or connector, then go to Step 10.
No | Go to the next step.
9 | INSPECT CONTROL CIRCUIT FOR OPEN CIRCUIT • Remove the PCM with PCM connector connected. • Inspect for continuity between the following terminals (harness-side): - Between EGR valve terminal E and PCM terminal 4D - Between EGR valve terminal A and PCM terminal 4G - Between EGR valve terminal B and PCM terminal 4J - Between EGR valve terminal F and PCM terminal 4M • Is there continuity? | Yes | Go to the next step.
No | Repair or replace harness for open circuit then go to the next step.
10 | VERIFY TROUBLESHOOTING OF DTC P0403 COMPLETED • Make sure to reconnect all disconnected connectors. • Clear the DTC from the PCM memory using the WDS or equivalent. • Turn the ignition switch off. • Start the engine and warm it up completely. • Is the PENDING CODE for this DTC present? | Yes | Replace the PCM, then go to the next step. (See PCM REMOVAL/INSTALLATION [L3 Turbo].)
No | Go to the next step.
11 | VERIFY AFTER REPAIR PROCEDURE • Perform the "After Repair Procedure". (See AFTER REPAIR PROCEDURE [L3 Turbo].) • Are any DTCs present? | Yes | Go to the applicable DTC inspection. (See DTC TABLE [L3 Turbo].)
No | Troubleshooting completed.