Question

What is the engine code P0121 on my 2011 GMC Sierra 1500 5.3L?

Answer 1

P0121 Throttle position sensor 1 performance

This is for the throttle position sensor, Contact the dealer GMC has a Campaign for this code situation what they would do is replace the throttle position sensor and reprogram the ECM, Being a Campaign it is considered as being a Recall TSB # 11273B

Answer 2

P0121 GMC - Throttle Position Sensor 1 Performance

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