P0406-EGR POSITION SENSOR CIRCUIT HIGHFor a complete wiring diagram Refer to Section 8W.When Monitored:With the ignition on. Battery voltage greater than 10 volts.Set Condition:EGR position sensor signal is greater than 4.89. One trip Fault.
Possible Causes(K34) EGR POSITION SENSOR SIGNAL CIRCUIT SHORTED TO THE (F856) 5-VOLT SUPPLY CIRCUIT(K34) EGR POSITION SENSOR SIGNAL CIRCUIT SHORTED TO BATTERY VOLTAGE(K34) EGR POSITION SENSOR SIGNAL CIRCUIT OPEN(K900) SENSOR GROUND CIRCUIT OPENEGR SOLENOID ASSEMBLYPCM
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING).Diagnostic Test1.EGR POSITION SENSOR VOLTAGE ABOVE 4.5 VOLTSStart the engine.With the scan tool, read the EGR Position Sensor voltage.Is the voltage above 4.5 volts?YesGo To 2NoGo To 82.(K34) EGR POSITION SENSOR SIGNAL CIRCUIT SHORTED TO THE (F856) 5-VOLT SUPPLY CIRCUITTurn the ignition off.Disconnect the EGR Solenoid harness connector.Disconnect the C1 and C2 PCM harness connectors.Measure the resistance between the (K34) EGR Position Sensor Signal circuit and the (F856) 5-volt Supply circuit in the EGR Solenoid harness connector.Is the resistance below 100 ohms?YesRepair the short between the (K34) EGR Position Sensor Signal circuit and the (F856) 5-volt Supply circuit.Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)NoGo To 33.(K34) EGR POSITION SENSOR SIGNAL CIRCUIT SHORTED TO BATTERY VOLTAGEIgnition on, engine not running.Measure the voltage on the (K34) EGR Sensor Signal circuit in the EGR Solenoid harness connector.Is the voltage above 0 volts?YesRepair the short to battery voltage in the (K34) EGR Position Sensor Signal circuit.Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)NoGo To 44.EGR SOLENOID ASSEMBLYTurn the ignition off.Connect the PCM harness connectors.Connect a jumper wire between the (K34) EGR Position Sensor Signal circuit and the (K900) Sensor ground circuit.With the scan tool, monitor the EGR Position Sensor voltage.Ignition on, engine not running.Is the voltage below 0.5 of a volt?YesReplace the EGR Solenoid Assembly.Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)NoGo To 5Remove the jumper wire before continuing.5.(K34) EGR POSITION SENSOR SIGNAL CIRCUIT OPENTurn the ignition off.Disconnect the C2 PCM harness connector.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 (K34) EGR Position Sensor Signal circuit from the EGR Solenoid harness connector to the appropriate terminal of special tool #8815.Is the resistance below 5.0 ohms?YesGo To 6NoRepair the open in the (K34) EGR Position Sensor Signal circuit.Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)6.(K900) SENSOR GROUND CIRCUIT OPENMeasure the resistance of the (K900) Sensor ground circuit from the EGR Solenoid harness connector to the appropriate terminal of special tool #8815.Is the resistance below 30 ohms?YesGo To 7NoRepair the open in the (K900) Sensor ground circuit.Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)7.PCMBefore 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?YesRepair as necessary.Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)NoReplace and program the Powertrain Control Module per Service Information.Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)8.EGR POSITION SENSOR SWEEPThe engine will run rough and possibly stall in the following test. Feather the accelerator pedal to keep the engine from stalling.Start the engine.With the scan tool, enter 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?YesRefer to the INTERMITTENT CONDITION Diagnostic Procedure.Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)NoReplace the EGR Solenoid Assembly.Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)