P0404

Diagnostic Chart (Part 1 Of 2):

Diagnostic Chart (Part 2 Of 2):

Engine Controls Schematics: PCM Emission Inputs:

CIRCUIT DESCRIPTION
The Powertrain Control Module (PCM) monitors the Exhaust Gas Recirculation (EGR) valve pintle position input to ensure that the valve responds properly to commands from the PCM. The PCM compares Actual EGR Position with Desired EGR Position when the valve is commanded open. If Actual EGR Position is 15 percent less than Desired EGR position when the PCM is commanding the EGR valve opened, DTC P404 will set.

CONDITIONS FOR RUNNING THE DTC
^ The following sensor Diagnostic Trouble Codes (DTCs) are not set:
- Throttle position (TP) sensor
- Mass Air Flow (MAF) sensor
- Heated Oxygen Sensor (HO2S)
- Intake Air Temperature (IAT) sensor
- Engine Coolant Temperature (ECT) sensor
^ Engine run time met The time ranges from 45 seconds to 8.5 minutes depending upon engine coolant temperature at start-up.
^ TP angle is more than 2 percent.
^ DTC P0401 diagnostic not running.
^ System voltage is more than 10 volts.

CONDITIONS FOR SETTING THE DTC
^ Actual EGR Position and Desired EGR Position disagree by more than 20 percent.
^ The above conditions are present for longer than 10 seconds.

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

The PCM will disable EGR for the rest of the ignition cycle.

CONDITIONS FOR CLEARING THE MIL/DTC
^ The PCM turns the MIL OFF after three consecutive drive trips during which the diagnostic runs and passes.
^ A last test failed, or the current DTC, clears when the diagnostic runs and passes.
^ A History DTC clears after forty consecutive warm-up cycles, if no other emission related diagnostic failures are reported.
^ Use a scan tool in order to clear the MIL diagnostic trouble code.
^ Interrupting the PCM battery voltage may or may not clear DTCs. This practice is not recommended. Refer to Powertrain Control Module (PCM) Description, Clearing Diagnostic Trouble Codes.

DIAGNOSTIC AIDS

NOTE: Refer to Connector Test Adapter Kit J 35616-A Notice in Service Precautions.

Check for excessive deposits on the EGR pintle or seat. Remove the EGR valve and check for deposits that may interfere with the EGR valve pintle extending completely or cause the pintle to stick.

Reviewing the Failure Records vehicle mileage since the diagnostic test last failed may help determine how often the condition occurs.

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

TEST DESCRIPTION
The numbers below refer to the step numbers on the diagnostic table.
2. This step verifies that the malfunction is present.
5. If DTC P0404 will only set under certain conditions, the malfunction may be intermittent. Refer to Diagnostic Aids. If an intermittent problem is suspected, check for poor connections at the PCM or the EGR valve. If the wiring and connections are OK and DTC P0404 continues to set, replace the EGR valve.
19. This vehicle is equipped with a PCM which utilizes an Electrically Erasable Programmable Read Only Memory (EEPROM). When the PCM is being replaced, the new PCM must be programmed.