P0405

DTC P0405

DTC DESCRIPTOR

DTC P0405
Exhaust Gas Recirculation (EGR) Position Sensor Circuit Low Voltage

DIAGNOSTIC FAULT INFORMATION






IMPORTANT: Always perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

TYPICAL SCAN TOOL DATA

EGR Position Sensor:

CIRCUIT/SYSTEM DESCRIPTION
The engine control module (ECM) uses the exhaust gas recirculation (EGR) position sensor to determine the position of the EGR valve. The ECM sends a reference voltage through the 5-volt reference circuit to the EGR position sensor. The ECM provides a voltage return path for the sensor through the low reference circuit. A variable voltage signal, based on the EGR valve position, is sent from the sensor to the ECM through the EGR position sensor signal circuit. If the ECM detects an EGR position sensor voltage that is less than the normal operating range, DTC P0405 sets.

CONDITIONS FOR RUNNING THE DTC
- DTCs P0698 and P0699 are not set.
- The ignition is ON.
- This DTC runs continuously when the above conditions are met.

CONDITIONS FOR SETTING THE DTC
- The EGR position sensor voltage is less than 0.26 volts.
- The above condition is present for more than 3 seconds.

ACTION TAKEN WHEN THE DTC SETS
- The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
- The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

CONDITIONS FOR CLEARING THE DTC
- The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
- A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
- A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
- Clear the MIL and the DTC with a scan tool.

CIRCUIT/SYSTEM VERIFICATION

IMPORTANT: If you cannot duplicate the condition, operate the vehicle within the conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records.

The EGR Position Sensor parameter is between 0.25-4.75 volts.

CIRCUIT/SYSTEM TESTING
1. With the ignition ON and the EGR valve disconnected, measure the voltage from the 5-volt reference circuit of the EGR valve to a good ground and observe that the DMM measures 4.98-5.02 volts.
- If the voltage is less than 4.98 volts, test for an open in the 5-volt reference circuit or for a faulty ECM.
2. With the ignition ON and the EGR valve disconnected, connect a jumper wire between the 5-volt reference circuit of the EGR valve and the signal circuit of the EGR valve and observe with a scan tool that the EGR sensor parameter displays 4.98-5.02 volts.
- If the EGR Sensor parameter is less than 4.98 volts, test the signal circuit for an open or short to ground, high resistance, or for a faulty ECM.
- If the 5-volt reference and the signal circuits, test normal replace the EGR valve.

REPAIR INSTRUCTIONS

IMPORTANT: Always perform the Diagnostic Repair Verification after completing the diagnostic procedure.
- Exhaust Gas Recirculation (EGR) Valve Replacement
- Control Module References for ECM replacement, setup, and programming.