Powertrain, generic · Vehicle speed, idle control and auxiliary inputs

P0536 A/C Evaporator Temperature Sensor Circuit Range/Performance

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. P0536 means the signal is valid but implausible – for example it differs from other temperature sensors after standstill, or does not drop after compressor engagement. Hella compares it with the cabin sensor with A/C off. Icing protection then works wrongly. No manufacturer document available to us uses this code; the description follows CARB's input component rules.

Likely causes

Sensor drifting
Sensor not seated correctly in the evaporator
Refrigerant shortage or compressor fault
Contact resistance in the connector

Symptoms

  • Fluctuating or weak cooling
  • Evaporator icing
  • Compressor switching off too early

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

P0535P0537P0538P0539P0534

References: hella.com, law.cornell.edu.