P1404

Diagnostic Chart:

Wiring Diagram:

The linear EGR system consists of a linear EGR valve, the PCM and its associated wiring. The EGR valve solenoid is controlled directly by the PCM when certain conditions have been met. The PCM contains a diode feedback circuit which dissipates energy when the valve is cycled Off. When the PCM commands the EGR valve closed, a closed valve position value is learned. If the PCM commands the valve closed and the actual feedback value does not match the learned value, DTC P1404 will set.

DTC PARAMETERS

DTC P1404 will set when the actual closed value does not match the learned closed value within 20 seconds if:

^ RPM is below 5000 and the actual vs learned is greater than 0.2 volts,

or

^ RPM is above 5000 and the actual vs learned is greater than 0.4 volts.

IMPORTANT: When the PCM recognizes that the parameters for setting P1404 have been set, the diagnostic software waits until the EGR cycles open 25% or greater three times and then retests. If after the three cycles the actual vs learned is not within the parameters, the DTC will be stored and the MIL (SERVICE ENGINE SOON) will be commanded On.

IMPORTANT: When this DTC sets, some EGR functions will be disabled for the duration of that ignition cycle. When repairs are complete, codes must be cleared to allow proper operation.


DIAGNOSTIC AIDS

When attempting to diagnose an intermittent problem, use the Scan tool to review malfunction history diagnostic information. The supplemental data can be used to duplicate a problem.

The purpose of this diagnostic is to find a sticking pintle in the EGR. Inspect the valve for debris, such as carbon holding the pintle off of the seat. Verily the pintle moves freely and the return spring forces the pintle closed.