What does it mean?
B1232 is a Body (airbags, seat belts, body electronics) fault code. It indicates: Short in the Evaporator Temperature Sensor Circuit .
Symptoms
- The AC compressor does not engage at all, or cycles on and off rapidly
- Vent air is cool but never becomes properly cold
- The evaporator temperature in live data is stuck at an extreme value
- On some systems the compressor runs continuously and the evaporator ices up, so airflow drops off after several minutes
- AC works briefly after start-up and then fades away
Likely causes
- Sensor signal wire shorted to ground where it passes along or through the heater box
- Internally shorted thermistor in the evaporator sensor probe
- Condensate leaking into the sensor connector and bridging the pins
- Harness pinched when the dash or HVAC housing was previously reassembled
- Signal wire shorted to a 12 V feed sharing the same loom, such as the blower circuit
- Failed input circuit inside the climate control module
How to fix it
- Read the evaporator temperature in live data and compare it with the actual vent outlet temperature
- Unplug the sensor at the HVAC case; if the code changes to an open circuit fault, the sensor is internally shorted
- Measure the sensor resistance at a known temperature and compare with the thermistor specification
- With both ends disconnected, test the signal wire for a short to ground and to battery positive
- Check for condensate entering the connector and make sure the evaporator drain is clear
- Replace the evaporator sensor if it is shorted, clear the code, and verify the compressor cycles normally