The linear exhaust gas recirculation (EGR) system consists of a linear EGR valve, the powertrain control module (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 values, DTC P1404 will set.

Important: When the PCM recognizes that the parameters for setting DTC P1404 have been set, the diagnostic software waits until the EGR cycles open 50 percent or greater 4 times and then resets. If after the 3 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, functions will be disabled. When repairs are complete, codes must be cleared and the ignition keyed OFF for at least 10 seconds to allow proper operation.

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

When attempting to diagnose an intermittent problem, use the scan tool to review the malfunction history diagnostic information. The supplimental 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. Verify the pintle moves freely and the return spring forces the pintle closed.