Chevy: Frozen DEF

This bulletin applies to 2022 Chevy Colorado and Express equipped with a 2.8L engine and 2022 Silverado equipped with a 6.6L diesel engine. DTC P105A and/or P208A may be set. Engineering has found that the DEF pump may be running when the exhaust fluid in the tank is frozen due to a software anomaly. According to the bulletin, Chevrolet engineering is working on a solution for this issue. 

To repair a vehicle with this condition, the DEF tank needs to be thawed. Verify that the DEF tank pump is operational. If any messages are on the DIC, run the Reductant System Tamper Service Bay test. If the code(s) clear, the DEF pump is operational. 

To avoid this from occurring again, tell the customer to drive the vehicle for at least 30 minutes daily if the ambient temperature is 5°F or colder. Keep the vehicle garaged if possible. Keep the DEF tank topped off. The system cannot recover on its own if the ambient temperature is less than -4°F. 

After the DEF has been warmed, shut the vehicle off for at least 10 seconds. Restart the vehicle and drive to restart the DEF pump. If successful, DIC warning should clear within 30 seconds of the drive start. It is normal for the Service Engine Soon light to remain on for three subsequent drive cycles.