B0423 on 2007-2019 GMC Sierra 3500HD — Air Temperature Control (Passenger/Right Side) Circuit Performance
1 vehicles · 1 makes · $180-$650 repair
Most Reported On
B0423 is an OBD-II diagnostic trouble code meaning “Air Temperature Control (Passenger/Right Side) Circuit Performance.” B0423 is an HVAC (climate control) code indicating a problem with the right/passenger-side air temperature control circuit, typically the temperature blend-door actuator that mixes hot and cold air. The climate control module is not getting the expected feedback position from this actuator, so the cabin temperature on that side may not match the setting. This is a comfort/convenience fault, not a safety issue. This code is most commonly reported on 2007-2019 GMC Sierra 3500HD, with repair costs ranging from $180 to $650.
Common Causes
Typical Repair Cost
Based on 1 documented vehicle-specific issues. Actual cost depends on root cause and vehicle.
Diagnostic Tools
To diagnose B0423, you'll need an OBD-II scanner. Here are our recommendations at every price point.
ANCEL AD310 Classic OBD-II Scanner
by ANCEL
A simple, affordable code reader that reads and clears check engine codes. Great for quick diagnostics on any OBD-II vehicle (1996+).
- Read & clear engine codes
- View freeze frame data
- I/M readiness status
- No batteries or app needed
BlueDriver Pro Bluetooth Scanner
by BlueDriver
Bluetooth OBD-II scanner with a free companion app. Provides enhanced diagnostics, smog readiness, and repair reports sourced from a database of verified fixes.
- Enhanced diagnostics (ABS, SRS, transmission)
- Repair Reports with verified fixes
- Smog check readiness
- Free app (iOS & Android)
LAUNCH CRP123X OBD-II Scanner
by LAUNCH
A professional-grade handheld scanner that reads all four major systems (engine, transmission, ABS, SRS) with live data streaming and graphing.
- Engine, transmission, ABS, SRS diagnostics
- Live data stream & graphing
- AutoVIN for vehicle identification
- Free lifetime updates via Wi-Fi
Autel MaxiCOM MK808S Diagnostic Tool
by Autel
Shop-level diagnostic tablet with bi-directional control, active tests, and full system coverage. Ideal for serious DIYers and small shops.
- All-system diagnostics (25+ modules)
- Bi-directional control & active tests
- Oil reset, EPB, BMS, TPMS, injector coding
- 7-inch touchscreen with Android OS
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FAQ
What does B0423 mean?
B0423 stands for "Air Temperature Control (Passenger/Right Side) Circuit Performance." B0423 is an HVAC (climate control) code indicating a problem with the right/passenger-side air temperature control circuit, typically the temperature blend-door actuator that mixes hot and cold air. The climate control module is not getting the expected feedback position from this actuator, so the cabin temperature on that side may not match the setting. This is a comfort/convenience fault, not a safety issue.
What are the most common causes of B0423?
The most common causes of B0423 are: Faulty passenger-side temperature blend-door actuator, Stuck or broken blend door, Open, shorted, or chafed actuator wiring, Corroded or loose actuator connector, Faulty HVAC control module, Poor ground to the actuator, Mechanical obstruction binding the blend door. The specific cause varies by vehicle.
How much does it cost to fix B0423?
Repair costs for B0423 range from $180 to $650, depending on the vehicle and root cause.
Which vehicles are affected by B0423?
Au7o has documented B0423 across 1 vehicle models from 1 manufacturers: GMC.
Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.