Note. If EGR valve shows signs of excessive heat, check the exhaust system for restriction or blockage (possible plugged catalytic converter).
Note. For circuit reference, see WIRING DIAGRAMS article.
Circuit Description
PCM monitors EGR valve pintle position input to ensure EGR valve responds properly to commands from the PCM. If PCM detects a pintle position signal voltage below the normal range of the pintle position sensor, or a signal voltage that is not within a tolerance considered acceptable for proper EGR system operation, the PCM will set DTC P1404. MIL will be illuminated when DTC P1404 is set on 2 consecutive trips.
Conditions required for setting this DTC are
- IAT is above 41°F (5°C).
- EGR actual position is 16 counts below the EGR low threshold for a least 6.3 seconds.
Diagnostic Aids
Check for excessive deposits on EGR valve pintle or pintle seat, or deposits that would prevent pintle from extending completely or cause the pintle to stick. Check for damage to wiring harness. While observing scan tool display for EGR position, perform a "wiggle test" of related wiring. A change in displayed value should indicate approximate location of fault.