Engine Oil Temperature Sensor Circuit (GM)
What does P1185 mean?
The P1185 code means the vehicle's onboard diagnostic system has detected: Engine Oil Temperature Sensor Circuit (GM). This is a low severity code.
Common Symptoms
- Check Engine Light on
- Oil life monitor may not calculate correctly
- No noticeable drivability symptoms
- Slightly extended warm-up fuel enrichment
- Possible minor fuel economy decrease
Probable Causes (Ranked by Likelihood)
- Faulty engine oil temperature sensor Very High
- Corroded sensor connector High
- Wiring issue in oil temperature circuit Moderate
- Low oil level affecting sensor reading Moderate
- PCM input fault Low
Step-by-Step Diagnostic Procedure
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Check engine oil level and condition
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Read oil temperature sensor data on a scan tool
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Compare oil temperature to coolant temperature after warm-up (should be similar)
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Inspect the sensor connector for corrosion or loose fit
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Test sensor resistance at known temperature
Frequently Asked Questions
Does P1185 affect the oil life monitor?
Yes. GM vehicles use oil temperature data to calculate the oil life percentage. If the sensor is faulty, the oil life monitor may not accurately track when oil changes are needed.
Where is the oil temperature sensor on GM trucks?
On GM trucks with the Gen IV V8 engine, the oil temperature sensor is typically located in the oil pan or near the oil filter housing. Location varies by model and engine type.
Can I ignore P1185?
While P1185 does not cause drivability problems, it keeps the Check Engine Light on and may affect the oil life monitor accuracy. It is a low-priority repair but should be addressed when convenient.