Circuit/System Verification
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 ON.
- Verify DTC P0121, P0122, P0123, P0222, P0223, P0562, P0621, P0622, or P2135 is not set.
- If any of the DTCs are set
Refer to Diagnostic Trouble Code (DTC) List - Vehicle for further diagnosis.
- If none of the DTCs are set
- If any of the DTCs are set
- Verify the scan tool TB Idle Airflow Compensation parameter is less than 90 %.
- 90 % or greater
Refer to Throttle Body Cleaning .
- If less than 90 %
- 90 % or greater
- Clear the DTCs with a scan tool.
- Ignition OFF and all vehicle systems OFF. It may take up to 2 minutes for all vehicle systems to power down.
- Ignition ON.
- Verify the scan tool TAC Motor parameter displays Enabled.
- If Disabled
Refer to Circuit/System Testing
- If Enabled
- If Disabled
- Verify DTC P1516, P2101, P2119, or P2176 is not set.
- If any of the DTCs are set
Refer to Circuit/System Testing
- If none of the DTCs are set
- If any of the DTCs are set
- Verify the scan tool TAC Motor parameter displays Enabled while performing the Throttle Sweep Test with a scan tool.
- If Disabled NOTE:
Before replacing the throttle body assembly, make sure the TAC motor control circuits are not shorted to B+.
Test or replace the Q38 throttle body assembly.
- If Enabled
- If Disabled
- Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
- Verify a DTC does not set.
- If any DTC sets
Refer to Diagnostic Trouble Code (DTC) List - Vehicle for further diagnosis.
- If no DTCs set
- If any DTC sets
- All OK
NOTE:
A low battery voltage or charging system condition may cause a DTC to set.
NOTE:
If there is a condition with the throttle body, the TAC Motor Command parameter will go to 99 % for a predetermined amount of time and then a DTC sets. Once a DTC is set, the TAC Motor Command parameter will go to 0 % and the TAC Motor parameter will display Disabled.