HVAC Evaporator Temperature Sensor Circuit
What does B1208 mean?
The B1208 code means the vehicle's onboard diagnostic system has detected: HVAC Evaporator Temperature Sensor Circuit. This is a low severity code.
Common Symptoms
- A/C blows warm intermittently
- Evaporator icing up and blocking airflow
- A/C compressor cycling too frequently
- Reduced A/C cooling performance
- Inconsistent air temperature from vents
Probable Causes (Ranked by Likelihood)
- Failed evaporator temperature sensor Very High
- Corroded sensor connector behind dashboard High
- Damaged wiring to evaporator sensor Moderate
- Sensor dislodged from evaporator fins Moderate
- HVAC control module not reading sensor Low
Step-by-Step Diagnostic Procedure
-
Read HVAC DTCs with scan tool
-
Monitor evaporator temperature sensor reading on live data
-
Compare sensor reading to actual evaporator temperature
-
Inspect sensor connector behind glove box area
-
Test sensor resistance and compare to specifications
Frequently Asked Questions
What does the evaporator temperature sensor do?
It monitors the evaporator core temperature to prevent it from freezing. If the evaporator gets too cold, the sensor signals the system to temporarily stop the compressor.
Can a bad sensor cause the evaporator to freeze?
Yes. If the sensor reads a temperature higher than actual, the system will not cycle the compressor off, allowing the evaporator to freeze and block all airflow.
Is the evaporator sensor hard to access?
It varies by vehicle. Some sensors are accessible behind the glove box, while others require partial dashboard removal. Labor is the main cost factor.