P1404

Refer to Engine Controls Schematics.

Diagnostic Chart (Part 1 Of 2):

Diagnostic Chart (Part 2 Of 2):

CIRCUIT DESCRIPTION
The PCM monitors the EGR valve pintle position input to ensure that the valve responds properly to commands from the PCM. When the ignition is turned on, the PCM learns the EGR closed valve pintle position. The PCM compares the learned EGR closed valve pintle position to the Actual EGR position when the EGR valve is commanded closed. If the Actual EGR position indicates that the EGR valve is still open when the PCM is commanding the EGR valve closed, DTC P1404 will set.

CONDITIONS FOR RUNNING THE DTC
^ IAT is more than -10°C (14°F).
^ Engine run time is achieved. The length of time ranges from 20 seconds to 6 minutes depending upon engine coolant temperature at startup.
^ System voltage is between 10.0 volts and 18.0 volts.
^ Desired EGR must equal zero.

CONDITIONS FOR SETTING THE DTC
^ EGR Feedback is 0.2 volt more than the EGR Closed Valve Pintle Position when the Desired EGR Position is commanded to 0 percent.
^ The above condition is present for longer than 20 seconds.

ACTION TAKEN WHEN THE DTC SETS
^ The PCM will illuminate the Malfunction Indicator Lamp (MIL) during the first 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 Failure Records data.

CONDITIONS FOR CLEARING THE MIL/DTC
^ The PCM will turn OFF the MIL 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
^ Inspect for excessive deposits on the EGR valve pintle or seat.
^ Remove the EGR valve and inspect for deposits that may interfere with the EGR valve pintle extending completely or cause the pintle to stick.

IMPORTANT: Remove any debris from the connector surfaces before servicing a component. Inspect the connector gaskets when diagnosing or replacing a component. Ensure that the gaskets are installed correctly. The gaskets prevent contaminate intrusion.

^ Poor terminal connection-Inspect the harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and faulty terminal to wire connection. Use a corresponding mating terminal to test for proper tension.
^ Damaged harness-Inspect the wiring harness for damage. If the harness inspection does not reveal a problem, observe the display on the scan tool while moving connectors and wiring harnesses related to the sensor. A change in the scan tool display may indicate the location of the fault.
^ PCM and engine grounds for clean and secure connections

If the DTC is determined to be intermittent, reviewing the Failure Records can be useful in determining when the DTC was last set.

TEST DESCRIPTION
The numbers below refer to the step numbers on the diagnostic table:
2. Verifies that the malfunction is present.
4. If DTC P1404 will only set under certain conditions, the malfunction may be intermittent. 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 P1404 continues to set, replace the EGR valve.
14. 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.