P0404

P0404-EGR POSITION SENSOR PERFORMANCE (DIESEL)





For a complete wiring diagram Refer to Diagrams/Electrical.

Theory of Operation


The EGR valve contains three hall effect sensors to detect position. The three position sensors correspond to 6 valid sectors that the valve can be in. If the valve position skips a sector(s), a fault counter is incriminated, else decremented. Once the counter equals a calibrated threshold, the rationality fault becomes active. The position sensors are integral to the valve assembly and are not serviced separately. The ECM will light the MIL lamp once the diagnostic runs and fails in two consecutive drive cycles. The ECM will turn off the MIL lamp once the diagnostic runs and passes in 4 consecutive drive cycles.

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

- Set Condition:
EGR solenoid internal position reading does not follow expected values.







Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. Initial Inspection and Diagnostic Overview .


Diagnostic Test


1. OTHER DTC'S
Ignition on engine off.
With a scan tool, read DTCs.
Do you have any additional EGR related DTC's?

Yes


- Repair all other DTC's first


No


- Replace EGR valve.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test