GMC Sierra
B0420
The B0420 code in a GMC Sierra T1XX (2019-Present) indicates an issue with the rear climate control sensor circuit, which may lead to improper functioning of the rear climate control system.
1 SolutionB-CodeBody
B
Error Code Type
Body
Components
1 affected
HVAC
Symptoms
5 common
- •Rear air conditioning not functioning properly
- •Fluctuating temperature from the rear HVAC system
- •Warning message on the dashboard related to HVAC
- +2 more
Most Affected Generations
1 generation
T1XX
1
Top Affected Components
1 component
HVAC
1
Severity Levels
1 level
medium
1
Quick Facts
1
Total Solutions
1
Affected Components
5
Common Symptoms
1
Generations
All Solutions
Showing 1 of 1 solution for error code B0420 across all generations.