Engine Oil Temp Sensor Circuit Open
The powertrain control module (PCM) has detected an open circuit in the engine oil temperature (EOT) sensor signal. This means the circuit resistance is infinite or exceeds the calibrated maximum threshold, preventing the PCM from reading oil temperature. As a result, the engine protection strategy based on oil temperature is disabled, and the fault code is stored.
1. Commonly Affected Makes
2. Most Common Causes
- Internally damaged engine oil temperature (EOT) sensor (open circuit)
- Cut, disconnected, or corroded wiring in the signal or return circuit
- Loose connector, bent pins, or excessive corrosion at the sensor connector
- Internal PCM failure (uncommon)
3. Symptoms You Will Notice
- Check Engine Light illuminated
- Possible reduced engine performance or limp mode
4. Step-by-Step Diagnosis
Scan for additional codes and check freeze frame data
Visually inspect the EOT sensor connector and wiring for damage or corrosion
Measure resistance across the EOT sensor terminals; compare to manufacturer specifications
Check for continuity in the signal and ground circuits between the sensor and PCM
If all else is normal, test the PCM output or replace the PCM as a last resort
5. Frequently Asked Questions
Is it safe to drive?▼
You can usually drive short distances, but avoid heavy loads or high RPMs since the engine lacks oil temperature protection. Have it diagnosed soon.
How much does it cost to fix?▼
Typically $150-$400, including parts (sensor $30-$100) and labor, depending on vehicle and shop rates.