P0406

DTC P0406

CIRCUIT DESCRIPTION
The exhaust gas recirculation (EGR) vacuum sensor is used to monitor the amount of vacuum that is available to the EGR valve. A low reference circuit, 5 volt reference circuit and a vacuum sensor signal circuit are used to interface the ECM with the EGR vacuum sensor. If the EGR vacuum sensor signal voltage is above a calibrated value, DTC P0406 sets.

CONDITIONS FOR RUNNING THE DTC
- DTC P0651 is not set.
- The ignition is ON.
- The Ignition 1 Signal parameter is between 11-18 volts.

CONDITIONS FOR SETTING THE DTC
- The EGR Vacuum Sensor parameter is more than 158 kPa.
- The above conditions are met for more than 5 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 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

Steps 1-2:

Steps 3-6:

Steps 7-13:

The numbers below refer to the step numbers on the diagnostic table.
2. If DTC P0651 sets, there is a short to voltage on the 5-volt reference circuit-Perform the DTC P0651 diagnostic before proceeding.