Circuit/System Testing
WARNING: This page is about a different car, the 2007 GMC Sierra and 2007 Chevrolet Silverado. However, it is still accessible from the selected car via links, so may be relevant.
The 5-volt reference circuit and the switch signal will have to be checked for shorts to ground, opens, high resistance, and shorts to voltage by following the below listed steps.
- Reference the mode switch supply voltage with a scan tool.
- The scan tool should indicate 4.8-5.2 volts. If the scan tool indicates the voltage is within this specification then with a jumper wire short the switch signal circuit pin 12 on the switch to the 5-volt reference circuit pin 11 on the switch. If the mode switch return voltage on the scan tool measures 4.8-5.2 volts then replace the switch.
- If the mode switch return does not read 4.8-5.2 volts check the switch signal circuit and the 5-volt reference circuits for a short to ground, short to voltage, open, or high resistance.
- If no shorts or high resistance are found on the switch signal or 5-volt reference circuits then replace the transfer case shift control module, reprogram, and complete the motor learn procedure.