Reduced engine power and an illuminated Check Engine MIL may be found on some 2019-2023 Silverado and Sierra models equipped with the 2.7L 4-cylinder turbo engine (RPO L3B). DTCs P0299 (Engine Underboost), P2227 (Barometric Pressure Sensor Performance) or P0300 (Engine Misfire Detected) may be set in the Engine Control Module (ECM).
These conditions may result from ambient or PCV moisture freezing where ice or sludge can accumulate in the Charge Air Cooler (CAC). An updated ECM calibration is available to address operating conditions in colder weather. In addition, a lower air baffle should be installed to help reduce CAC icing. (Fig. 8)
Fig. 8
To install the air baffle, begin by removing the front bumper impact bar and then the Throttle Inlet Absolute Pressure (TIAP) sensor. (Fig. 9) Use a fluid extractor or suction tool to drain any remaining moisture from the CAC end tank and reinstall the TIAP sensor and bolt.
Fig. 9
Next, remove the four push pins that secure the top of the front bumper lower air baffle. (Fig. 10)
Fig. 10
Install the new radiator air front lower baffle by slipping the tabs behind the outermost tabs of the front bumper lower air baffle. Snap the top of the radiator air front lower baffle in place on top of the CAC. (Fig. 11)
Fig. 11
Reinstall the four push pins to secure the front bumper lower air baffle.
Once repairs are complete, reprogram the ECM with the updated calibration.
Refer to Bulletin #23-NA-002 for more information, including part numbers.
– Thanks to Matt Gager
