DTC P0403: EGR Control Circuit: Testing
- Turn ignition on, engine not running. With the DRBIII®, read DTCs and record the related Freeze Frame data. Is the Good Trip counter displayed and equal to zero? If yes, go to next step. If no, go to step 9.
- Turn the ignition off. Disconnect the EGR Solenoid harness connector. Turn ignition on, engine not running. Turn all accessories off. Using a 12-volt test light connected to the EGR Solenoid ground circuit, probe the EGR Solenoid Control circuit at the EGR Solenoid harness connector. With the DRBIII®, actuate the EGR solenoid. Does the 12-volt test light flash on and off? If yes, replace the EGR Solenoid Assembly. If no, go to next step.
- Turn the ignition off. Disconnect the PCM harness connectors. Using a 12-volt test light connected to the EGR Solenoid Ground circuit, probe the EGR Solenoid Control circuit at the EGR Solenoid harness connector. Does the test light illuminate? If yes, go to next step. If no, repair the open in the EGR Solenoid Ground circuit.
- Turn ignition on, engine not running. Measure the voltage on the EGR Solenoid Control circuit at the EGR Solenoid harness connector. Is the voltage above 1.0 volt? If yes, repair the short to voltage in the EGR Solenoid Control circuit. If no, go to next step.
- Turn the ignition off. Measure the resistance between ground and the EGR Solenoid Control circuit at the EGR Solenoid harness connector. Is the resistance below 100 ohms? If yes, repair the short to ground in the EGR Solenoid Control circuit. If no, go to next step.
- Measure the resistance between the EGR Solenoid Control circuit and the Sensor Ground circuit at the EGR Solenoid harness connector. Is the resistance below 5.0 ohms? If yes, repair the short to Sensor Ground circuit in the EGR Solenoid Control circuit. If no, go to next step.
- Measure the resistance of the EGR Solenoid Control circuit from the EGR Solenoid harness connector to the appropriate terminal at Miller Special Tool. Is the resistance below 5.0 ohms? If yes, go to next step. If no, repair the open in the EGR Solenoid Control circuit.
- There are no possible causes remaining, replace PCM. Program the new PCM. See PROGRAMMING .
- The conditions that set the DTC are not present at this time. The following may help in identifying the intermittent condition. With the engine running at normal operating temperature, monitor the DRBIII® parameters related to the DTC while wiggling the wiring harness. Look for parameter values to change and/or a DTC to set. Review the DRBIII® Freeze Frame information. If possible, try to duplicate the conditions under which the DTC was set. Refer to any Technical Service Bulletins (TSB) that may apply. Visually inspect the related wiring harness. Look for any chafed, pierced, pinched, or partially broken wires. Visually inspect the related wiring harness connectors. Look for broken, bent, pushed out, or corroded terminals. Were any of the above conditions present? If yes, repair as necessary. If no, test is complete.
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. Use Miller Special Tool (8815) when performing diagnosis at PCM harness connectors.
NOTE:
Before continuing, check the PCM harness connectors for corrosion, damage or terminal push out. Repair as necessary.
WARNING:
When the engine is operating, do not stand in a direct line with the fan. Do not put your hands near the pulleys, belts or fan. Do not wear loose clothing.