P0404

P0404-EGR CONTROL CIRCUIT PERFORMANCE





For a complete wiring diagram, refer to the Wiring Information.

Theory of Operation

The Exhaust Gas Recirculation (EGR) Valve is opened by a motor located on top of the EGR valve. The EGR Valve is spring loaded closed. The motor electronically opens the valve and is controlled by the Powertrain Control Module (PCM). The EGR Valve motor contains three position sensors that detect to location of the EGR Valve. The three position sensors correspond to six valid sectors that the valve can be in. If the valve position skips a sector(s), a fault counter will increment by one. Once the counter equals a calibrated threshold, the rationality fault becomes active. The position sensors are integral to the EGR Valve assembly and are not serviced separately. The PCM lights the MIL lamp immediately after this diagnostic runs and fails. During this time the PCM will stop controlling the EGR valve. The default position for the valve is closed. The PCM will turn off the MIL lamp after the diagnostic runs and passes in four consecutive drive cycles.

- When Monitored:
Key on, engine off and while running.

- Set Condition:
The Powertrain Control Module (PCM) detects an overheat condition on the EGR control circuit.





Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. Pre-Diagnostic Troubleshooting Procedure.
OTHER DTCs
1. Ignition on engine off.
2. With the scan tool, erase DTCs.
3. Turn the ignition off for 75 seconds.
4. Start the vehicle. It may be necessary to drive vehicle to reset DTC.
5. With the scan tool, read DTCs.

Do you have any additional EGR related DTCs?

Yes

- Repair all other EGR DTCs and retest.

No

- Replace the Powertrain Control Module.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.