AutoCodes - OBDII Code List - B0408
B0408 - Front Temperature Control Circuit
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B0408 Possible Causes
- Faulty Air Temperature Actuator
- Air Temperature Actuator harness is open or shorted
- Air Temperature Actuator circuit poor electrical connection
- Faulty Heating, Ventilation, and Air Conditioning (HVAC) Control Module
How do I fix code B0408?
Check the "Possible Causes" listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector's pins.
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Cost of diagnosing the B0408 code
Labor: 1.0
The cost of diagnosing the B0408 code is 1.0 hour of labor. The auto repair labor rates vary by location, your vehicle's make and model, and even your engine type. Most auto repairs shops charge between $75 and $150 per hour.Possible Symptoms
- Engine Light ON (or Service Engine Soon Warning Light)
B0408 Description
Stepper motors are used for temperature regulation, air distribution control and recirculation door control. With the switches and dials on the HVAC controls, air temperature door position, mode door position and recirculation door position can be selected. The selected values are passed to the Heating, Ventilation, and Air Conditioning (HVAC) Control Module via serial data. The HVAC control module supplies a 12 V reference voltage to the stepper motors and energizes the 4 stepper motor coils with a pulsed ground signal. The stepper motors move the appropriate doors into the calculated positions, in order to reach the desired positions.
More Information
Need more information on how to fix the B0408 code?Get Access to Factory Service Manuals
Information for specific makes
- B0408 BUICK Front Temperature Control Circuit
- B0408 CADILLAC Front Temperature Control Circuit
- B0408 CHEVROLET Front Temperature Control Circuit
- B0408 GMC Front Temperature Control Circuit
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