P1404

Schematic:

CIRCUIT DESCRIPTION

The Powertrain Control Module (PCM) monitors the EGR valve pintle position input to ensure that the valve responds properly to commands from the PCM. When the ignition switch is turned ON, the PCM monitors 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
^ None of the following DTCs are set:
- Throttle Position (TP) sensor
- Vehicle Speed Sensor (VSS)
- Misfire
- Intake Air Temperature (IAT) sensor
- Manifold Absolute Pressure (MAP) sensor
- Idle speed
- Fuel injector
- Engine Coolant Temperature (ECT) sensor
- Crankshaft Position (CKP) sensor
- Mass Air Flow (MAF) sensor
^ The system voltage is between 9 and 16 volts.

CONDITIONS FOR SETTING THE DTC
^ The EGR feedback is 0.4 volt more than the EGR closed valve pintle position when the Desired EGR Position is commanded to 0 percent.
^ The above conditions have to be present 4 times.

ACTION TAKEN WHEN THE DTC SETS
^ The PCM will illuminate the Malfunction Indicator Lamp (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 Failure Records data.
^ If the misfire is determined to be catalyst damaging, the PCM will flash the MIL.

Steps 1 - 8:

Steps 9 - 14:

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
Check for the following conditions:
^ Excessive deposits on the EGR valve 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.
^ A faulty connection at the PCM or the EGR valve-Inspect the harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and faulty terminal to wire connections.
^ Inspect the wiring harness for damage. If the wiring appears to be OK, connect a Digital Multimeter (DMM) and check the circuit continuity while moving the connectors and wiring harnesses related to the EGR valve. A change in the DMM display will indicate the location of the malfunction.