P0403
SYMPTOM
P0403-EGR SOLENOID CIRCUIT
WHEN MONITORED
Engine running. Battery voltage greater than 10 volts.
SET CONDITION
The EGR solenoid control circuit is not in the expected state when requested to operate by the PCM. One Trip Fault.
POSSIBLE CAUSES
- (Z958) EGR SOLENOID GROUND CIRCUIT OPEN
- (K35) EGR SOLENOID CONTROL CIRCUIT SHORTED TO BATTERY VOLTAGE
- (K35) EGR SOLENOID CONTROL CIRCUIT SHORTED TO GROUND
- (K35) EGR SOLENOID CONTROL CIRCUIT SHORTED TO THE (K900) SENSOR GROUND CIRCUIT
- (K35) EGR SOLENOID CONTROL CIRCUIT OPEN
- EGR SOLENOID ASSEMBLY
- PCM
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. Scan Tool Testing and Procedures
DIAGNOSTIC TEST
1. ACTIVE DTC
Ignition on, engine not running.
With a scan tool, read DTCs.
Is the DTC active at this time?
Yes>> Go To 2
No>> Perform (NGC) POWERTRAIN VERIFICATION TEST VER-5. Powertrain Verification Test - Ver 5
2. EGR SOLENOID ASSEMBLY
Turn the ignition off.
Disconnect the EGR Solenoid harness connector.
Ignition on, engine not running.
Turn off all accessories.
Using a 1 2-volt test light connected to the (Z958) EGR Solenoid ground circuit, probe the (K34) EGR Solenoid Control circuit.
With a scan tool, actuate the EGR solenoid.
Does the 12-volt test light flash on and off?
Yes>> Replace the EGR Solenoid Assembly. Perform (NGC) POWERTRAIN VERIFICATION TEST VER-5.
No>> Go To 3
3. (Z958) EGR SOLENOID GROUND CIRCUIT OPEN
Turn the ignition off.
Disconnect the PCM harness connectors.
Using a 12-volt test light connected to the 12-volts, probe the (Z958) EGR Solenoid ground circuit in the EGR Solenoid harness connector.
Does the test light illuminate brightly?
Yes>> Go To 4
No>> Repair the open in the (Z958) EGR Solenoid ground circuit. Perform (NGC) POWERTRAIN VERIFICATION TEST VER-5.
4. (K35) EGR SOLENOID CONTROL CIRCUIT SHORTED TO BATTERY VOLTAGE
Ignition on, engine not running.
Measure the voltage on the (K35) EGR Solenoid Control circuit in the EGR Solenoid connector.
Is the voltage above 1.0 volt?
Yes>> Repair the short to battery voltage in the (K35) EGR Solenoid Control circuit. Perform (NGC) POWERTRAIN VERIFICATION TEST VER-5.
No>> Go To 5
5. (K35) EGR SOLENOID CONTROL CIRCUIT SHORTED TO GROUND
Turn the ignition off.
Measure the resistance between ground and the (K35) EGR Solenoid
Control circuit in the EGR Solenoid harness connector.
Is the resistance below 100 ohms?
Yes>> Repair the short to ground in the (K35) EGR Solenoid Control circuit. Perform (NGC) POWERTRAIN VERIFICATION TEST VER-5.
No>> Go To 6
6. (K35) EGR SOLENOID CONTROL CIRCUIT SHORTED TO THE (K900) SENSOR GROUND CIRCUIT
Measure the resistance between the (K35) EGR Solenoid Control circuit and the (K900) Sensor ground circuit in the EGR Solenoid connector.
Is the resistance below 5.0 ohms?
Yes>> Repair the short between the (K900) Sensor ground circuit and the (K35) EGR Solenoid Control circuit. Perform (NGC) POWERTRAIN VERIFICATION TEST VER-5.
No>> Go To 7
7. (K35) EGR SOLENOID CONTROL CIRCUIT OPEN
CAUTION: Do not probe the PCM harness connectors. Probing the PCM harness connectors will damage the PCM terminals resulting in poor terminal to pin connection. Install Miller Special Tool # 8815 to perform diagnosis.
Measure the resistance of the (K35) EGR Solenoid Control circuit from the EGR Solenoid harness connector to the appropriate terminal of special tool # 8815.
Is the resistance below 5.0 ohms?
Yes>> Go To 8
No>> Repair the open in the (K35) EGR Solenoid Control circuit. Perform (NGC) POWERTRAIN VERIFICATION TEST VER-5.
8. PCM
Note: Before continuing, check the PCM harness connector terminals for corrosion, damage, or terminal push out. Repair as necessary.
Using the schematics as a guide, inspect the wire harness and connectors. Pay particular attention to all Power and Ground circuits.
Were there any problems found?
Yes>> Repair as necessary. Perform (NGC) POWERTRAIN VERIFICATION TEST VER-5.
No>> Replace and program the Powertrain Control Module per Service Information. Perform (NGC) POWERTRAIN VERIFICATION TEST VER-5.