The Check Engine MIL may be illuminated on some 2020-2021 CT4 models equipped with the 2.0L engine (RPO LSY) or 2.7L engine (RPO L3B) and some 2020-2021 CT5 models equipped with the 3.0L engine (RPO LGY) when operated in cold climates. The HVAC module temperature actuators stall detection can be unstable at times in cold climates (less than 59°F or 15°C), resulting in incorrect stall detection and several DTCs set.
If these conditions are found, replace the affected HVAC module temperature actuator with a new actuator. The automatic HVAC system has the following air control doors and associated actuators: mode, left temperature, right temperature, and recirculation. Refer to the Programmable Temperature Valve Actuator Replacement procedure for the left (Fig. 11) or right (Fig. 12) side in the appropriate Service Information.
Fig. 11
Fig. 12
Actuator Recalibration
The actuator recalibration procedure for the Body Control Module must be performed after replacing the temperature valve actuator on the left side. Do not operate any HVAC controls while the system is calibrating, which may interrupt the process and result in improper HVAC performance.
For more information, including part numbers, refer to Bulletin #21-NA-133.
– Thanks to Blake Streling
