DTC P0406: EGR Position Sensor High: Testing

Start the engine. With the DRBIII®, read the EGR Position Sensor voltage. Is the voltage above 4.5 volts? If yes, go to next step. If no, go to step 8.
Turn the ignition off. Disconnect the EGR Solenoid harness connector. Disconnect the PCM harness connectors. Measure the resistance between the EGR Sensor Signal circuit and the 5-Volt Supply circuit at the EGR Solenoid harness connector. Is the resistance below 100 ohms? If yes, repair the EGR Sensor Signal circuit for a short to the 5-Volt Supply circuit. If no, go to next step.
Ensure the ignition is off. Reconnect the PCM harness connectors. Turn ignition on, engine not running. Measure the voltage of the EGR Sensor Signal circuit in the EGR Solenoid harness connector. Is the voltage above 5.2 volts? If yes, repair the short to battery voltage in the EGR Sensor Signal circuit. If no, go to next step.
Connect a jumper wire between the EGR Sensor Signal circuit and the Sensor Ground circuit at the EGR Solenoid harness connector. With the DRBIII®, monitor the EGR Position Sensor voltage. Turn ignition on, engine not running. Is the voltage below 0.5 vo1t? If yes, replace the EGR Solenoid Assembly. If no, go to next step.

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.

Turn the ignition off. Disconnect the PCM harness connectors. Measure the resistance of the EGR Sensor Signal 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 Sensor Signal circuit.
Measure the resistance of the Sensor Ground 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 Sensor Ground circuit.

NOTE: Before continuing, check the PCM harness connectors for corrosion, damage or terminal push out. Repair as necessary.

There are no possible causes remaining, replace PCM. Program the new PCM. See PROGRAMMING .
Start the engine. The engine will run rough and possibly stall in the following test. Feather the accelerator panel to keep the engine from stalling. With the DRBIII®, enter Engine System Test and then EGR System Test. Push the 4=VARIABLE function. Monitor the EGR voltage while slowly pushing the up arrow. Is the voltage change smooth? If yes, go to next step. If no, replace the EGR Solenoid Assembly.

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.

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.