Circuit/System Testing
WARNING: This page is about a different car, the 2010 GMC Sierra, 2010 GMC Cab & Chassis Sierra, 2010 Chevrolet Silverado, and 2010 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.
- Ignition OFF, transmission in Park, disconnect the automatic transmission shift lever harness connector.
- Ignition OFF, all vehicle systems OFF, this may take up to 2 minutes, test for less than 5 ohms between the ground circuit terminal 2 and ground.
- If greater than the specified value, test the ground circuit for an open/high resistance.
- Ignition ON, test for greater than 11 V between the tow/haul signal circuit terminal 1 and ground.
- If less than the specified value, test the ignition voltage circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
- Ignition OFF, test for less than 3 ohms between terminal 1 and terminal 2 on the automatic transmission shift lever component harness connector while depressing the Tow/Haul switch button, and an open circuit when the Tow/Haul switch button is released.
- If not the expected results, replace the automatic transmission shift lever.
- If all circuits test normal, replace the BCM.