General Motors has issued a service update for certain examples of the Chevy Silverado HD and GMC Sierra HD pickup trucks equipped with the 6.6L L5P V8 Duramax diesel engine due to an issue related to the NOx sensor and engine control unit.
The problem: in affected vehicles, the Malfunction Indicator Lamp (MIL) or ‘Service Engine Soon’ light may appear illuminated on the instrument panel. GM service technicians may also find a diagnostic trouble code (DTC) of P11D5 when trying to assess the problem with the vehicle.
The hazards: this problem does not pose a safety risk to the driver or vehicle occupants. Most owners will not want to drive around with a MIL or Service Engine Soon light illuminated on the instrument panel, however.
The fix: dealers are instructed to reprogram the engine control module. The service bulletin indicates this correction applies to vehicles registered in cold weather US states as well as Canadian provinces.
- 2021 Chevy Silverado 2500 HD
- 2021 Chevy Silverado 3500 HD
- 2021 GMC Sierra 2500 HD
- 2021 GMC Sierra 3500 HD
Affected components: NOx sensor, engine control module.
Number of affected vehicles: GM did not say how many vehicles are affected by this problem.
Owners should: owners of affected GM SUVs will be contacted by the automaker and instructed to make an appointment with their dealer. Those owners who may be unsure whether or not their vehicle is affected by this recall can visit my.gm.com/recalls and type in their VIN to view any open recalls or other actions that may be active on it. Concerned parties can also reach out to GM directly using the contact information included below.
- GM recall number: N212331790
- Chevrolet Customer Service: 1-800-222-1020
- GMC Customer Service: 1-800-462-8782
- NHTSA Toll Free: 1-888-327-4236
- NHTSA (TTY): 1-800-424-9153