P0404

Circuit Description
The PCM monitors the 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% less than Desired EGR position when the PCM is commanding the EGR valve opened, DTC P0404 will set.

Conditions for Running the DTC
^ EGR icing is not possible.
^ EGR is not overtemp.
^ Sensor supply to EGR is good.
^ Desired EGR is not 0%.
^ No TP or Idle speed sensor DTCs set.
^ System voltage is above 10 volts.

Conditions for Setting the DTC
^ Actual EGR position is 15% less or more than the Desired EGR Position.
^ The above conditions are present for longer than 20 seconds.

Action Taken When the DTC Sets
^ The PCM will illuminate the MIL during the second consecutive trip in which the diagnostic test has been run and failed.
^ The PCM will store conditions which were present when the DTC set as Freeze Frame and Fail Records data.

Conditions for Clearing the MIL/DTC
^ The PCM will turn the MIL OFF during the third consecutive trip in which the diagnostic has been run and passed.
^ The history DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction.
^ The DTC can be cleared by using a scan tool.

Diagnostic Aids
Check for the following condition(s):
^ 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.
^ Poor connection at PCM or EGR Valve.
Inspect harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and poor terminal to wire connection.
^ Damaged harness.
Inspect the wiring harness for damage. If the harness appears to be OK, connect a digital multimeter and check circuit continuity while moving connectors and wiring harnesses related to the EGR valve. A change in the display will indicate the location of the malfunction.
Reviewing the Fail Records vehicle mileage since the diagnostic test last failed may help determine how often the condition that caused the DTC to be set.

Test Description
Number(s) below refer to the step number(s) on the Diagnostic Table:
2. Verifies that the malfunction is present.
3. If DTC P0404 will only set under certain conditions, the malfunction may be intermittent; Go to Diagnostic Aids. If an intermittent wiring problem is not present, check for a poor connection at the PCM or the EGR valve. If the connections are OK and DTC P0404 continues to set, replace the EGR valve.
16. 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. Refer to PCM Replacement/Programming.