Clean a GM throttle body

Clean a GM electronic throttle body and perform an idle relearn

Follow these steps to clean a GM electronic throttle body

Remove the intake air duct between the air filter box and the throttle body

Disconnect the evaporative emission

GM electronic throttle body

(EVAP) purge line hose from the throttle body and mark it’s location

Remove the four throttle body retaining bolts

Remove the throttle body assembly and the throttle body gasket

Spray throttle body cleaner on a clean shop rag. Manually open the throttle plate and wipe off the carbon buildup from the throat of the throttle body. Repeat to remove carbon from the throttle plate itself.

Do NOT spray throttle body cleaner directly onto the throttle plate, throttle plate shaft or the throat of the throttle body. Liquid throttle body cleaner and seep into the electronics portion of the throttle body, causing damage to the electronics.

Clean the MAF sensor

See this post for MAF cleaning instructions

Reinstall the throttle body to the intake manifold

Reinstall the throttle body

Apply medium threadlocker to the bolt threads. Using a new gasket, install the four retaining bolts onto the throttle body and reinstall it onto the intake manifold. Tighten to 89 IN/lbs.

Install the EVAP purge line hose and reassemble the air intake duct.

Perform idle relearn procedure

Start the engine and allow it to idle in PARK for 3 minutes.

The ECM/PCM should start to learn the new idle cells and the RPM should start to decrease.

Turn the  Ignition OFF for 60 seconds.

Start the engine and allow it to idle in PARK for 3 minutes.

After the 3 minute run time the engine should be idling normal.

If the idle speed does not relearn:

Drive the vehicle at speeds above 44 mph, performing with several decelerations and extended idles.

If the engine idle speed still has not been learned, turn the ignition OFF for 60 seconds and drive the vehicle AGAIN at speeds above 44 mph, performing with several decelerations and extended idles.

NOTE: GM states that the air filter must match the factory airflow and construction. Aftermarket “cold air” filters affect laminar air flow and may cause the MAF sensor to provide inaccurate readings.

©, 2018 Rick Muscoplat