The P0538: A/C Evaporator Temperature Sensor Circuit High code indicates that the A/C evaporator temperature sensor is reporting a temperature reading that is higher than expected. This can cause the A/C system to operate inefficiently, leading to poor cooling or the A/C system shutting down to prevent damage.
P0538 – Quick Overview
| Code | Information |
|---|---|
| Meaning | P0538: A/C Evaporator Temperature Sensor Circuit High |
| Is it serious? | No, but it can result in poor A/C performance or cause the system to stop functioning to avoid damage. |
| Possible causes | – Faulty A/C evaporator temperature sensor – High refrigerant pressure – Wiring issue |
| How to diagnose? | – Test the A/C evaporator temperature sensor – Check refrigerant pressure – Inspect wiring and connectors |
P0538 Meaning
The P0538: A/C Evaporator Temperature Sensor Circuit High code is triggered when the engine control module (ECM) detects a higher-than-expected temperature reading from the A/C evaporator temperature sensor. This could indicate a faulty sensor, high refrigerant pressure, or a wiring problem that’s causing inaccurate readings.
Step-by-step diagnostic guide
| Action | Description | Tools Needed |
|---|---|---|
| Check for Other Codes | Use an OBD-II scanner to check for any related fault codes that may provide additional insights into the A/C system issue. | OBD-II Scanner |
| Test the A/C Evaporator Temperature Sensor | Use a multimeter or diagnostic tool to measure the sensor’s output and verify whether it is reading accurately. Compare the sensor’s output with the manufacturer’s specifications. | Multimeter, Diagnostic Tool |
| Check Refrigerant Pressure | Use an A/C gauge set to check the refrigerant pressure in the system to ensure it is within the correct range specified by the manufacturer. | A/C Gauge Set |
| Inspect Wiring and Connectors | Check the wiring and connectors for any signs of damage, disconnection, or corrosion that could cause erratic sensor readings. | Flashlight, Multimeter |
| Clear the Code and Test the A/C System | After repairs, clear the code using an OBD-II scanner and test the A/C system to confirm that the issue is resolved. | OBD-II Scanner, Vehicle Manual |
| Recheck for Codes | Re-scan the vehicle after the test drive to ensure that the P0538 code hasn’t returned. | OBD-II Scanner |
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Hi, I am Juraj “Yuri” Lukacko. I got frustrated by unhelpful and scammy mechanics, so I decided to learn everything about car diagnostics myself. I test dozens of new car diagnostic tools every month along with learning new strategies to fix and customize cars. About Juraj Lukacko (Yuri)