Circuit/System Testing
NOTE:
You must perform the Circuit/System Verification before proceeding with Circuit/System Testing.
- Ignition OFF, disconnect the harness connector at the appropriate temperature sensor as determined in the Circuit/System Verification.
- Ignition OFF and all vehicle systems OFF. It may take up to 2 minutes for all vehicle systems to power down. Test for less than 5 Ω between the appropriate low reference circuit terminal 2 or B and ground.
- If greater than the specified range, test the appropriate low reference circuit for an open/high resistance. If the circuit tests normal, replace the K20 ECM.
- Ignition ON, verify the scan tool parameter of the appropriate temperature sensor is colder than -39°C (-38°F).
- If warmer than the specified range, test the appropriate signal circuit terminal 1 or A for a short to ground. If the circuit tests normal, replace the K20 ECM.
- Install a 3A fused jumper wire between the appropriate signal circuit terminal 1 or A and ground. Verify the appropriate scan tool parameter is warmer than 148°C (298°F).
- If colder than the specified range, test the appropriate signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the K20 ECM.
- If all circuits test normal, test or replace the appropriate temperature sensor.
NOTE:
If a short to voltage is found on the sensor signal circuit, the 3A fuse in the jumper wire will open.