For 1990-2009 cars only
Diagnostic Instructions
| • | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
| • | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
| • | Diagnostic Procedure Instructions provide an overview of each diagnostic category. |
Diagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
High Idle Switch Signal | High Idle | No High Idle | -- | -- |
Ground | -- | No High Idle | -- | -- |
Reference Information
Schematic Reference
Connector End View Reference
Electrical Information Reference
Scan Tool Reference
Circuit/System Verification
Ignition ON, observe the scan tool High Idle switch parameter while exercising the switch. The reading should change between ON/OFF.
Circuit/System Testing
- Ignition OFF, disconnect the harness connector at the high idle switch.
- Test for less than 5 ohms of resistance between the ground circuit terminal A and ground.
- Ignition ON, verify the scan tool High Idle switch parameter is OFF.
- Install a 3A fused jumper wire between the signal circuit terminal C and ground. Verify the scan tool High Idle switch parameter is ON.
- If all circuits test normal, test or replace the high idle switch.
| ⇒ | If greater than 5 ohms, test the ground circuit for an open/high resistance. |
| ⇒ | If not OFF, test the signal circuit for a short to ground. If the circuit tests normal, replace the ECM. |
| ⇒ | If not ON, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the ECM. |
Component Testing
- Ignition OFF, disconnect the harness connector at the high idle switch.
- Test for infinite resistance between the signal terminal C and the ground circuit terminal A with the switch in the open position.
- Test for less than 1 ohm between the signal terminal C and the ground terminal A with the switch in the closed position.
| ⇒ | If less than infinite resistance, replace the high idle switch. |
| ⇒ | If greater than 1 ohm, replace the high idle switch. |
