P0404

DTC P0404

CIRCUIT DESCRIPTION




The DTC P0404 Exhaust Gas Recirculation (EGR) Open Position Performance monitors EGR valve movement. The EGR valve position sensor is monitored by the powertrain control module (PCM). The 5-volt reference circuit, low reference circuit and the EGR valve position signal circuit are used by the PCM to determine the EGR valve position. The PCM compares the EGR Position Sensor parameter with the desired EGR Position parameter when the valve is commanded open or closed. If the PCM detects a calibrated difference between the EGR Position Sensor parameter and desired EGR Position parameter for a calibrated amount of time, this DTC sets.

DTC DESCRIPTORS
This diagnostic procedure supports the following DTC.
DTC P0404 Exhaust Gas Recirculation (EGR) Open Position Performance

CONDITIONS FOR RUNNING THE DTC
- DTC P0030, P0050, P0107, P0108, P0112, P0113, P0117, P0118, P0135, P0155, P0335, P0336, P0401, P0403, P0406, P0641, P0651, P1128, P1129, P2413, P2414, and P2415 are not set.
- The battery voltage is at least 10.5 volts
- The EGR valve is commanded open to at least 0.25 mm (0.010 in).
- Engine speed is less than 4,000 RPM.
- DTC P0404 runs once per drive cycle once the above conditions have been met.

CONDITIONS FOR SETTING THE DTC
- The difference between the desired EGR position and the measured EGR position, as determined by the EGR position sensor, is more than 1.020 mm (0.041 in).
- The above condition is present for more than 5 seconds

ACTION TAKEN WHEN THE DTC SETS
- The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
- The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

CONDITIONS FOR CLEARING THE MIL/DTC
- The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
- A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
- A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
- Clear the MIL and the DTC with a scan tool.

DIAGNOSTIC AIDS
- Inspect for excessive deposits on the EGR pintle or seat. Inspect for deposits that may interfere with the EGR valve pintle extending completely or cause the pintle to stick.
- If the condition is intermittent, refer to Intermittent Conditions. Intermittent Conditions

TEST DESCRIPTION

Steps 1-10:

Steps 11-21:

The number below refers to the step number on the diagnostic table.
5. This step tests for high resistance in reference voltage circuit. If the test lamp does not illuminates at all, there is excessive resistance in the 5-volt reference circuit or low reference ground circuit.
8. This step tests for high resistance in the EGR solenoid control circuit and ground circuits. The PCM provides a 12 volt bias signal on the solenoid control circuit that is pulled low when the solenoid is OK and has a good ground. If the circuit resistance is OK, the DMM should measure ignition voltage.
19. After replacing the PCM a new minimum throttle position and idle speed must be established.