Diagnostic Aids
WARNING: This page is about a different car, the 2009 GMC Yukon and 2009 Chevrolet Tahoe. However, it is still accessible from the selected car via links, so may be relevant.
- Inspect the connectors at the TCM, the AT ISS, and all other circuit connecting points for an intermittent condition. Refer to Testing for Intermittent Conditions and Poor Connections .
- Inspect the circuit wiring for an intermittent condition. Refer to Testing for Electrical Intermittents .
- Road test the vehicle while monitoring the Transmission ISS parameter on the scan tool. The Transmission ISS parameter should vary with engine speed changes and not abruptly drop out.
- Inspect for an open or shorted AT ISS wire.
- Inspect for a disconnected AT ISS connector.
- Inspect for a faulty AT ISS.