DTC P0403 [LF, L3]


DTC P0403	EGR valve (stepper motor) circuit malfunction
DETECTION CONDITION	• The PCM monitors the input voltage from the EGR valve. If the voltage at PCM terminals 4E, 4H, 4K and/or 4N remain low or high, the PCM determines that the EGR valve circuit has a malfunction. Diagnostic support note • This is a continuous monitor (CCM). • The MIL illuminates if the PCM detects the above malfunction conditions in two consecutive drive cycles or in one drive cycle while the DTC for the same malfunction has been stored in the PCM. • The PENDING CODE is available if the PCM detects the above malfunction condition during first drive cycle. • The FREEZE FRAME DATA is available. • The DTC is stored in the PCM memory.
POSSIBLE CAUSE	• EGR valve malfunction • Connector or terminal malfunction • Short to power circuit in wiring harness between EGR valve terminal E and PCM terminal 4E • Short to power circuit in wiring harness between EGR valve terminal A and PCM terminal 4H • Short to power circuit in wiring harness between EGR valve terminal B and PCM terminal 4K • Short to power circuit in wiring harness between EGR valve terminal F and PCM terminal 4N • Short to ground circuit in wiring harness between EGR valve terminal E and PCM terminal 4E • Short to ground circuit in wiring harness between EGR valve terminal A and PCM terminal 4H • Short to ground circuit in wiring harness between EGR valve terminal B and PCM terminal 4K • Short to ground circuit in wiring harness between EGR valve terminal F and PCM terminal 4N • Open circuit in wiring harness between EGR valve terminal E and PCM terminal 4E • Open circuit in wiring harness between EGR valve terminal A and PCM terminal 4H • Open circuit in wiring harness between EGR valve terminal B and PCM terminal 4K • Open circuit in wiring harness between EGR valve terminal F and PCM terminal 4N • Open circuit in wiring harness between main relay terminal D and EGR valve terminal C • Open circuit in wiring harness between main relay terminal D and EGR valve terminal D • PCM malfunction


STEP	INSPECTION		ACTION
1	PERFORM DTC CONFIRMATION PROCEDURE • Perform the DTC CONFIRMATION PROCEDURE. (See [LF, L3].) • Is the same DTC present?	Yes	Go to the next step.
1		No	Intermittent concern exists. Go to the INTERMITTENT CONCERN TROUBLESHOOTING procedure. (See INTERMITTENT CONCERN TROUBLESHOOTING [LF, L3].)
2	INSPECT EGR VALVE FOR POOR CONNECTION • Turn the ignition switch to the OFF position. • Disconnect the EGR valve connector. • Inspect for poor connection (damaged, pulled-out terminals, corrosion, etc.). • Is there any malfunction?	Yes	Repair or replace the terminals and/or connector, then go to Step 9.
2		No	Go to the next step.
3	INSPECT POWER CIRCUIT for an open circuit CIRCUIT • Turn the ignition key to ON (Engine off). • Measure the voltage at the following terminals and body ground. - EGR valve terminal C - EGR valve terminal D • Is the voltage B+?	Yes	Go to the next step.
3		No	Repair or replace the wiring harness for an open circuit circuit then go to Step 9.
4	INSPECT EGR VALVE • Perform the EGR valve inspection. (See EGR VALVE INSPECTION [LF, L3].) • Is the EGR valve normal?	Yes	Go to the next step.
4		No	Replace the EGR valve, then go to Step 9.
5	INSPECT CONTROL CIRCUIT FOR SHORT TO GROUND • Turn the ignition switch to the OFF position. • Inspect for continuity following terminals and body ground: - EGR valve terminal E - EGR valve terminal A - EGR valve terminal B - EGR valve terminal F • is there continuity?	Yes	Repair or replace the wiring harness for a short to ground, then go to Step 9.
5		No	Go to the next step.
6	INSPECT CONTROL CIRCUIT FOR SHORT TO POWER • Turn the ignition switch key to ON (Engine off). • Measure the voltage the following terminals and body ground: - EGR valve terminal E - EGR valve terminal A - EGR valve terminal B - EGR valve terminal F • Is the voltage B+?	Yes	Repair or replace the wiring harness for short to power, then go to Step 9.
6		No	Go to the next step.
7	INSPECT PCM FOR POOR CONNECTION • Turn the ignition switch to the OFF position. • Disconnect the PCM connector. • Inspect for poor connection (damaged, pulled-out terminals, corrosion, etc.). • Is there any malfunction?	Yes	Repair or replace the terminals and/or connector, then go to Step 9.
7		No	Go to the next step.
8	INSPECT CONTROL CIRCUIT for an open circuit CIRCUIT • Remove the PCM with the PCM connector connected. • Inspect for continuity between the following terminals: - Between EGR valve terminal E and PCM terminal 4E - Between EGR valve terminal A and PCM terminal 4H - Between EGR valve terminal B and PCM terminal 4K - Between EGR valve terminal F and PCM terminal 4N • Is there continuity?	Yes	Go to the next step.
8		No	Repair or replace the wiring harness for an open circuit circuit then go to the next step.
9	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. • Perform the KOEO/KOER self-test. (See KOEO/KOER SELF-TEST [LF, L3].) • Is the same DTC present?	Yes	Replace the PCM, then go to the next step. (See PCM REMOVAL/INSTALLATION [LF, L3].)
9		No	Go to the next step.
10	VERIFY AFTER REPAIR PROCEDURE • Perform the "After Repair Procedure". (See AFTER REPAIR PROCEDURE [LF, L3].) • Are any DTCs present?	Yes	Go to the applicable DTC troubleshooting. (See DTC TABLE [LF, L3].)
10		No	Troubleshooting completed.