Some 2020-2021 Silverado and Sierra models equipped with the 3.0L turbocharged Duramax diesel engine (RPO LM2) may exhibit a lack of performance along with DTCs P003A (Turbocharger Boost Control Position Exceeded Learning Limit), P0046 (Turbocharger Boost Control Position Performance), P0299 (Engine Underboost) and/or P0234 (Engine Overboost). If these conditions are found, check for loose bolts on the turbocharger actuator. (Fig. 18)
Fig. 18
If any of the three actuator bolts are not fully seated (Fig. 19), the threads may be damaged and the turbocharger should be replaced. The actuator is not available as a service part.
If all the bolts are fully seats, continued with the diagnostics outlined in the appropriate Service Information.
Fig. 19
– Thanks to Robert Bastien
