Engine

P0195 — Engine Oil Temperature Sensor Circuit Malfunction

Severity: medium Drive with care, to a shop

What P0195 means

P0195 means the engine control unit detected a problem in the engine oil temperature sensor circuit, with a signal outside the expected range or not plausible. The sensor changes resistance with oil temperature, and the control unit reads the resulting voltage to calculate it. This data is used for engine strategies and the dashboard readout.

Symptoms

  • Check Engine light on
  • Erratic or wrong oil temperature gauge readings
  • Slight drop in fuel economy
  • Possible hesitation when accelerating
  • Reduced power on some diesels

Possible causes

  1. Failed engine oil temperature sensor
  2. Damaged wiring or corroded connector at the sensor
  3. Open circuit or short to ground or voltage in the sensor circuit
  4. Poor reference voltage or ground from the control unit
  5. Low oil level leaving the sensor exposed
  6. Internal control unit input fault (uncommon)

How to diagnose

  1. Read codes and freeze frame data, then clear the code and see if it returns
  2. Check oil level and condition
  3. Inspect the sensor, connector and harness, especially near the oil filter housing, for chafing, oil and corrosion
  4. Compare scan tool oil temperature with actual temperature on a cold engine
  5. Measure sensor resistance and compare it with specifications for your vehicle
  6. Check reference voltage and ground at the sensor connector
  7. Test the wiring to the control unit for opens and shorts
  8. If the sensor and wiring are good, test the control unit

Common fixes

  • Replace the oil temperature sensor with an OEM or equivalent part
  • Repair or replace damaged wiring and connectors
  • Correct the oil level or change the oil if that was the cause
  • Reprogram or replace the control unit if its input circuit is confirmed faulty

P0195 on different brands

Ford · manuals
Ford uses an extended P0195:16 code meaning the oil temperature sensor "A" circuit voltage is below the threshold; it describes the detected circuit condition, not necessarily a failed sensor.

Questions and answers

Can I drive with a P0195 code?

Usually yes, for short and careful trips. Bad data can hurt engine operation, so have it diagnosed soon.

What most often causes P0195?

Most often it is the oil temperature sensor itself or damaged wiring and connectors. Start by inspecting the harness and checking the oil level.

Will the code go away after the repair?

Clear it with a scan tool after fixing the cause. If the fault is truly resolved, it should not come back.

This is general information about the code. The meaning can differ between makes and models: a scan tool and the repair manual for your car will show the exact cause.