Powertrain, generic · Vehicle speed, idle control and auxiliary inputs
P0537 A/C Evaporator Temperature Sensor Circuit Low
Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modeNo
The evaporator temperature sensor, an NTC thermistor behind the evaporator, prevents icing: near 0–3 °C the compressor is switched off or reduced. Usually the climate module reads it and reports body codes; P0535–P0539 only arise where the engine module controls the compressor and reads the sensor. P0537 means the signal voltage is below its limit; with the usual NTC voltage divider that is a signal shorted to ground or a shorted sensor, read as implausibly warm – icing protection may then fail. No manufacturer document available to us uses this code; the description follows CARB's input component rules.
Likely causes
Signal line shorted to ground
Sensor shorted internally
Condensate in the connector (leakage to ground)
Engine module
Symptoms
- Air conditioning not cooling
- Possible icing
- Compressor permanently on or locked out
Repair estimate
DifficultyMediumDIY possible
Parts and labour€30–400
Time0.5–4 h
Typical range across vehicles; the real cost depends on what the testing finds.
Parts involved
evaporator temperature sensorsensor wiringengine control module
Related codes
References: en.wikipedia.org, hella.com, law.cornell.edu.