Throttle body carbon build-up: idle surge, reduced engine power, throttle DTCs (high mileage)

Applies toThe bulletin lists GMC Yukon 2006 - 2018.

Yukon 2006 - 2018— [1] Models

Why it happensAs carbon builds up in the throttle body of a high-mileage vehicle, the ECM/PCM learns to compensate by increasing the throttle plate angle.

As carbon builds up in the throttle body of a high mileage vehicle, the ECM/PCM learns to compensate by increasing the throttle plate angle.— [1] Condition

First signsWith enough carbon, idle surge, deceleration surge, tip-in hesitation, reduced engine power mode and/or DTCs may occur.

If enough carbon builds up, an idle surge, deceleration surge, tip-in hesitation, reduced engine power mode, and/or DTCs— [1] Condition

How to confirmIf SI diagnosis does not isolate the cause, inspect the throttle body bore and plate for obvious carbon build-up.

If SI diagnosis does not isolate the cause of this concern, inspect the throttle body bore and plate for obvious carbon build up.— [1] Recommendations

RepairIf carbon is present, follow the Throttle Body Cleaning Procedure in SI.

If carbon is present, follow the Throttle Body Cleaning Procedure in SI to clean the throttle body.— [1] Recommendations

RepairDepending on the vehicle, the idle learn reset/reset idle learn is normally found on the Tech 2 ECM menu for Module Set Up or Special Functions/TAC System.

Notice: Depending on the vehicle you are working on, the 3idle learn reset/reset idle learn3 is normally found on the Tech 2 ECM menu for Module Set Up or Special Functions/TAC System.— [2]

RepairAfter ensuring that the throttle body bore and plate are clean, perform an idle learn reset/reset idle learn with the Tech 2/GDS and re-evaluate the concern.

After ensuring that the throttle body bore and plate are clean, perform an 3idle learn reset/reset idle learn3 with the Tech 2/GDS and re-evaluate the concern.— [2]

CautionIf the throttle body is cleaned without performing an idle learn reset/reset idle learn with the Tech 2, the ECM/PCM may continue to compensate for the previous carbon build up, and the concern may return along with DTCs P0121, P0506 and/or P0507.

If the throttle body is cleaned without performing an 3idle learn reset/reset idle learn3 with the Tech 2, the ECM/PCM may continue to compensate for previous carbon build up, causing it to return with a similar concern as well as DTCs P0121, P0506, and/or P0507.— [2]

CautionIf the ECM/PCM of a high mileage vehicle is replaced and/or reprogrammed without performing the Throttle/Idle Learn outlined in SI, it may no longer compensate for existing carbon build up in the throttle body.

if the ECM/PCM of a high mileage vehicle is replaced and/or reprogrammed without performing the Throttle/Idle Learn outlined in SI, the ECM/PCM may no longer compensate for existing carbon build up in the throttle body— [2]