Circuit/System Testing (w/TAC)
- Ignition OFF, disconnect the harness connector at the throttle body assembly.
- Ignition OFF, test for 5 ohms or less of resistance between the low reference circuit terminal 4 and ground.
- If greater than the specified range, test the low reference circuit for a short to voltage, or an open/high resistance. If the circuit tests normal, replace the ECM.
- Ignition ON, test for 4.8-5.2 volts between the 5-volt reference circuit terminal 1 and ground.
- If less than the specified range, test the 5-volt reference circuit for a short to ground or open/high resistance. If the circuit tests normal, replace the ECM.
- If greater than the specified range, test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the ECM.
- Verify both scan tool TP sensor percentage parameters are between 80-88 percent.
- TP sensor 1 signal circuit terminal 3
- TP sensor 2 signal circuit terminal 2
- If less than the specified range, test the appropriate signal circuit for a short to ground. If the circuit tests normal, replace the ECM.
- If greater than the specified range, test the appropriate signal circuit for a short to voltage. If the circuit tests normal, replace the ECM.
- Install a 3A fused jumper wire between TP sensor 1 signal circuit terminal 3 and ground. Verify the scan tool TP sensor 1 percentage parameter is less than 2 percent.
- If greater than the specified range, test the signal circuit for an open/high resistance. If the circuit tests normal, replace the ECM.
- Install a 3A fused jumper wire between TP sensor 2 signal circuit terminal 2 and the 5-volt reference circuit terminal 1. Verify the scan tool TP sensor 2 percentage parameter is less than 2 percent.
- If greater than the specified range, test the signal circuit for an open/high resistance. If the circuit tests normal, replace the ECM.
- If all circuits test normal, test or replace the throttle body assembly.