What Does P0537 Mean?
The A/C evaporator temperature sensor is reporting a voltage signal that is below the normal operating range, indicating a low circuit condition. For most NTC (negative temperature coefficient) sensors, low voltage corresponds to a very high temperature reading, which is implausible for an operating evaporator. The driver may notice the A/C compressor running continuously without cycling off, potentially leading to evaporator freeze-up.
Common Causes
35%
Evaporator temperature sensor shorted internally, producing a low-resistance/low-voltage signal
30%
Short to ground in the sensor signal wire between the sensor and PCM
20%
Corroded or water-damaged connector creating a low-resistance path to ground
15%
PCM internal pull-up resistor or input circuit fault
Diagnostic Steps
1
Check the evaporator temperature sensor PID on the scan tool — if it reads an implausibly high temperature (e.g., 200°F+), the sensor or circuit is shorted low.
2
Disconnect the evaporator temperature sensor connector and check if the voltage at the PCM/module side rises to approximately 5V (or reference voltage) — if it does, the fault is in the sensor; if it stays low, the wiring is shorted to ground.
3
Measure the sensor resistance with a DVOM — a good NTC sensor should read 10K-15K ohms at room temperature; near 0 ohms confirms an internal short.
4
Inspect the wiring harness from the sensor to the module, particularly where it passes through the HVAC housing or behind the dashboard, for pinched or chafed wires that could short to the metal housing.
5
Check for water intrusion at the sensor connector — evaporator condensation or a clogged drain tube can cause moisture buildup that creates low-resistance paths.
Estimated Repair Cost
$80 - $350
Parts + labor, varies by vehicle and location
The A/C evaporator temperature sensor is reporting a voltage signal that is below the normal operating range, indicating a low circuit condition. For most NTC (negative temperature coefficient) sensors, low voltage corresponds to a very high temperature reading, which is implausible for an operating...
The most common cause of P0537 (A/C Evaporator Temperature Sensor Circuit Low) is: Evaporator temperature sensor shorted internally, producing a low-resistance/low-voltage signal
Typical repair costs for P0537 range from $80 to $350, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Safe to drive. The A/C compressor may run continuously because the PCM thinks the evaporator is very warm, which can cause evaporator freeze-up and reduced airflow. This does not affect vehicle safety or drivability.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P0537 to identify the root cause.
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Quick Info
Category
Powertrain
System
A/C & Climate Control
Difficulty
Type
Generic (SAE)
Recommended Tools
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