A/C Evaporator Temperature Sensor Circuit Malfunction
The P0535 code indicates a problem in the A/C evaporator temperature sensor circuit. This sensor monitors the temperature of the evaporator core to prevent freezing and regulate A/C operation. The PCM detects a voltage signal outside the expected range, often due to a faulty sensor, wiring issues, or a short circuit. This can cause the A/C compressor to cycle improperly or not engage, leading to poor cooling performance.
01. Most Common Causes
- Faulty A/C evaporator temperature sensor
- Open or shorted wiring in the sensor circuit
- Poor electrical connection at the sensor connector
- Corroded or damaged sensor terminals
- Failed PCM (rare)
02. Symptoms You Will Notice
- A/C system blows warm air or insufficient cooling
- A/C compressor cycles on and off rapidly
- Check Engine Light illuminated
- Evaporator freezing up (ice on A/C components)
03. Step-by-Step Diagnosis
Step 1: Use an OBD2 scanner to confirm P0535 and check for other codes.
Step 2: Visually inspect the evaporator temperature sensor and its wiring for damage, corrosion, or loose connections.
Step 3: Test the sensor's resistance with a multimeter; compare to manufacturer specifications (typically 2-10 kΩ at room temperature).
Step 4: Check for voltage and ground at the sensor connector with the ignition on; should be around 5V reference signal.
Step 5: If sensor and wiring are okay, test the PCM's ability to read the sensor signal; consider PCM replacement only after ruling out other causes.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
Yes, but the A/C may not work properly. Driving without A/C is safe, but if the evaporator freezes, it could restrict airflow and cause discomfort. It's best to diagnose and repair soon.
How much does it cost to fix?▼
Typically $50-$150 for parts and labor. The sensor itself is inexpensive ($10-$30), but labor costs vary. If wiring repair is needed, costs may be higher.