Circuit/System Testing
WARNING: This page is about a different car, the 2010 Pontiac G5 and 2010 Chevrolet Cobalt. However, it is still accessible from the selected car via links, so may be relevant.
- Disconnect the ECM harness connector X1.
- Measure for 1,300-1,500 ohms at 25°C (77°F) between the VSS high signal circuit terminal 54 and the VSS low signal circuit terminal 34.
- If the value is greater than 1,500 ohms test the VSS high signal circuit and the VSS low signal circuit for an open/high resistance. If the circuits/connections test normal, replace the vehicle speed sensor.
- If the value is less than 1,300 ohms test the VSS high signal and the VSS low signal circuits for a shorted together condition. If the circuits/connections test normal, replace the vehicle speed sensor.
- Measure for more than 10 ohms of resistance between the VSS high signal circuit terminal 54 and ground.
- If the value is less than the specified range, repair the short to ground.
- Measure for more than 10 ohms of resistance between the VSS low signal circuit terminal 34 and ground.
- If the value is less than the specified range, repair the short to ground.
- Reconnect the ECM connector. Disconnect the VSS connector.
- Ignition OFF, test for less than 5 ohms between the low reference circuit at the VSS harness connector terminal A and ground.
- If greater than the specified value, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the ECM.
- Ignition ON, test for less than 6 V between the signal circuit at the VSS harness connector terminal B and ground.
- If greater than the specified value, test the signal circuit for a short to voltage. If the circuit tests normal, replace the ECM.