Circuit/System Testing
WARNING: This page is about a different car, the 2009 GMC Sierra, 2009 GMC Cab & Chassis Sierra, 2009 Chevrolet Silverado, and 2009 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.
- Ignition OFF, disconnect both harness connectors at EGT sensor 1 and sensor 2.
- Ignition OFF and scan tool disconnected for 90 seconds, Measure for a resistance of less than 5 Ω on each low reference circuit between terminals B and ground.
- If greater than the specified range, repair the open/high resistance on the affected circuit. If the circuit tests normal, replace the ECM.
- Ignition OFF, disconnect the X1 harness connector at the ECM.
- Test for less than 5 Ω between the signal circuit terminal A of the EGT sensor 1 and the corresponding terminal 69 X1 of the ECM.
- If greater than the specified range, repair the open/high resistance in the circuit.
- Test for less than 5 Ω between the signal circuit terminal A of the EGT sensor 2 and the corresponding terminal 93 X1 of the ECM.
- If greater than the specified range, repair the open/high resistance in the circuit.
- If all circuits test normal, test or replace the affected sensor.
NOTE:
Perform the Repair Verification after completing the Circuit/System Testing.