Circuit/System Testing

WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2012 GMC Yukon XL, 2012 GMC Yukon, 2012 Chevrolet Tahoe, 2012 Chevrolet Suburban, and 2012 Chevrolet Avalanche. 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 electrical connector.
Ignition OFF, test for less than 1 ohm between terminal 2 on the automatic transmission shift lever vehicle harness connector and ground at the battery negative post.
- If 1 Ω or greater
1. Ignition OFF.
2. Test for less than 1 Ω in the ground circuit wire from both ends of the wire.
  - If 1 Ω or greater, repair the open/high resistance in the wire circuit.
  - If less than 1 Ω, repair the open/high resistance in the ground connection or the terminal connection at the automatic transmission shift lever.
- If less than 1 Ω
Ignition ON, test for greater than 11 volts on the signal circuit terminal 1 on the automatic transmission shift lever vehicle harness connector and ground at the battery negative post.
- If less than 11 volts
1. Ignition OFF.
2. Test for less than 1 Ω in the signal circuit wire from both ends of the wire.
  - If 1 Ω or greater, repair the open/high resistance in the signal circuit wire.
  - If less than 1 Ω, repair the open/high resistance in either terminals on the signal circuit wire.
- If greater than 11 volts
Ignition OFF, test for less than 3 olms between terminal 1 and terminal 2 on the automatic transmission shift lever component harness connector while depressing the Tow/Haul switch button.
- If greater than 3 Ω
  Replace the automatic transmission shift lever assembly.
- If less 3 Ω
If all circuits test normal, replace the BCM.