Diagnostic Aids
WARNING: This page is about a different car, the 2008 GMC Sierra, 2008 GMC Cab & Chassis Sierra, 2008 Chevrolet Silverado, and 2008 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.
- A slight to moderate resistance in either signal or low reference circuit can widen the spread between the two EGR temperature sensors and cause this DTC to set.
- An EGR temperature sensor that is skewed lower at various ambient temperatures, due to more resistance than is normal, can widen the spread between the two sensors and cause this DTC to set. Measure and record the resistance of both EGR temperature sensors 1 and 2 at ambient temperature. Compare those measurements to the Temperature Versus Resistance (EGR Temperature Sensors) or Temperature Versus Resistance (ECT Sensors) or Temperature Versus Resistance (Fuel Temperature Sensor) or Temperature Versus Resistance (IAT Sensor 1) or Temperature Versus Resistance (IAT Sensor 2) or Temperature Versus Resistance (EGT Sensors) .
- Inspect both EGR temperature sensors terminals for corrosion and for poor connections. It is very important that a thorough inspection of the wiring and connectors be performed. Failure to fully inspect wiring and connectors may result in misdiagnosis, causing part replacement with reappearance of the malfunction.
- EGR temperature sensors may fail while operating under extreme temperatures. Review the Freeze Frame/Failure Records to verify the failure criteria.