P0406

DTC P0406






CIRCUIT DESCRIPTION
This diagnostic monitors the exhaust gas recirculation (EGR) valve position sensor. The position sensor is mounted within the EGR valve and is part of the EGR valve assembly. A 5-volt reference circuit, a low reference circuit, and a signal circuit are used by the powertrain control module (PCM) to determine the EGR valve position. If the PCM detects the EGR valve position sensor signal voltage is pulled above a calibrated value, this DTC sets.

DTC DESCRIPTOR
This diagnostic procedure supports the following DTC:
DTC P0406 Exhaust Gas Recirculation (EGR) Position Sensor Circuit High Voltage

CONDITIONS FOR RUNNING THE DTC
- The engine is running.
- DTC P0406 runs continuously.

CONDITIONS FOR SETTING THE DTC
- The EGR Position Sensor parameter is more than 4.88 volts.
- The above condition is present for more than 2 seconds.

ACTION TAKEN WHEN THE DTC SETS
- The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.
- The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame/Failure Records.

CONDITIONS FOR CLEARING THE MIL/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.

TEST DESCRIPTION

Step 1 - Step 12:

Step 13:

The numbers below refer to the step numbers on the diagnostic table.
1. The Diagnostic System Check - Vehicle prompts the technician to complete some basic checks and store the Freeze Frame data on the scan tool if applicable. This creates an electronic copy of the data taken when the fault occurred. The information is then stored in the scan tool for later reference.
4. This step tests for a short to voltage on the EGR position sensor signal circuit. With the sensor disconnected, the signal circuit should be near 0 volts.
11. After replacing the PCM, a new minimum throttle position and idle speed must be established.