P0404

CIRCUIT DESCRIPTION
The Powertrain Control Module (PCM) monitors the Exhaust Gas Recirculation (EGR) valve pintle position input in order to ensure that the valve responds properly to commands from the PCM. The PCM compares the EGR position sensor with desired EGR position when the valve is commanded open. If the difference between the EGR position sensor and desired EGR position is more than 15 percent this Diagnostic Trouble Code (DTC) will set.

CONDITIONS FOR RUNNING THE DTC
The system voltage is greater than 10 volts.

The EGR valve is enabled.

CONDITIONS FOR SETTING THE DTC
^ The difference between the EGR position sensor and the desired EGR position is more than 15 percent.
^ The condition is present for more than 25 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.
^ The PCM disables the EGR valve for the ignition cycle

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.
^ Use a scan tool in order to clear the MIL and the DTC.

DIAGNOSTIC AIDS
Inspect for the following conditions:

Excessive deposits on the EGR pintle or seat- Remove the EGR valve, and inspect for deposits that may interfere with the EGR valve pintle extending completely or may cause the pintle to stick.

If the condition is intermittent, refer to Intermittent Conditions. Intermittent Conditions

TEST DESCRIPTION

Steps 1-10:

Steps 11-17:

The numbers below refer to the step numbers on the diagnostic table:
2. This step verifies that the malfunction is present.
3. If DTC P0404 will only set during certain conditions, the malfunction may be intermittent. Refer to Diagnostic Aids. If an intermittent wiring condition is not present, test for a faulty connection at the PCM or the EGR valve. If the connections are OK and if DTC P0404 continues to set, replace the EGR valve.