We had a 2013 Cadillac Escalade in the shop throwing a P0121 code, which is a Throttle Position Sensor failure. Right away, all the signs point to a dirty throttle body. A simple Throttle Body Cleaning cures many low-rpm rough-running engines and trouble codes surrounding throttle body, throttle position and even mass air flow sensors.

GM Throttle Body Cleaning Tools

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Tools Needed for Throttle Body Cleaning

We took this opportunity to use our cordless Milwaukee M12 FUEL ratchets as well. We covered these ratchets in our Best of Milwaukee NPS17 breakdown. Speaking of tools, there are only 3 needed for removing and replacing the throttle body. An 8mm socket will remove the two hose clamps, and a 10mm socket removes the negative battery cable, the two 10mm nuts, and the two 10mm bolts holding on the throttle body. A pair of needle-nose pliers removes the only plastic clip that holds the intake tube to the radiator hose. Once removed, we used some CRC Throttle Body and Intake cleaner to remove the grease and grime from the throttle body. An old toothbrush will help in this process as well. After several liberal doses of CRC Cleaner and toothbrush scrubbing, the throttle body is clean and ready for reassembly.

It is critical that you remove the negative battery cable first, and it should be the last thing reattached. This ensures that we’re not confusing the computers when removing and moving the throttle blade.

Even with the cable removed, once the throttle body is replaced, the computer will need to relearn itself to the clean throttle body. For the past thousands of miles, it has been adjusting itself as the throttle body continues to get dirtier.

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Reassembly After Throttle Body Cleaning

Replacement of the throttle body is the same process, in reverse. We use the 3/8″ Milwaukee M12 ratchet with the 10mm socket to install the throttle body. Then, we reattach the throttle body wiring connection (throttle position sensor). Finally, we use the 1/4″ Milwaukee M12 ratchet with the 8mm socket to tighten the two hose clamps on the intake tubes. The last piece is to reattach the negative battery cable with the same 10mm socket, and we’re ready for startup.