Faulty oil temperature sensor (internal open or short circuit, or drifted readings); Damaged, chafed or oil-soaked wiring to the sensor; Corroded, loose or contaminated sensor connector or terminals; Oil leak soaking the sensor connector or harness and affecting the signal; Wiring short to earth, to a supply voltage or open circuit elsewhere in the harness; Fault in the engine control unit or its sensor reference supply or earth.

P0195

Engine Oil Temperature Sensor A Circuit.

Generic
Powertrain
Generic code
Low severity

How this code is built

P: SystemPowertrain
0: Defined bySAE, the same on every car
1: AreaFuel and air metering
95: FaultThe specific fault in that area

What it means

P0195 is the generic code for a fault in the engine oil temperature sensor 'A' circuit. The engine control unit has seen a signal from the sensor that is missing, out of range or does not make sense, for example a voltage stuck at the top or bottom of its range or a reading that does not follow engine warm-up. Not every engine has an oil temperature sensor, and its location and use vary by model and engine.

Symptoms

Engine warning light on
Oil temperature gauge or display reading nothing, stuck or erratic (where fitted)
Cooling fan or oil cooler behaviour that seems wrong on some models
Reduced performance or a limp mode on some models if oil temperature is used for engine protection
Usually no noticeable change in how the engine runs

Possible causes

Faulty oil temperature sensor (internal open or short circuit, or drifted readings)likely
Damaged, chafed or oil-soaked wiring to the sensorlikely
Corroded, loose or contaminated sensor connector or terminalslikely
Oil leak soaking the sensor connector or harness and affecting the signalpossible
Wiring short to earth, to a supply voltage or open circuit elsewhere in the harnesspossible
Fault in the engine control unit or its sensor reference supply or earthrare

How to diagnose

Read all stored and pending codes and note the freeze frame data, including engine temperature and run time when the code set
Check the engine oil level and condition, and look for oil leaks around the sensor and connector, as the correct level matters for oil temperature readings
Inspect the sensor, its connector and the nearby wiring for damage, chafing, heat damage, oil contamination and corrosion
With the engine cold, compare the live oil temperature reading with the coolant and intake air temperature, which should be similar
Watch the live oil temperature as the engine warms up to see whether it rises smoothly or sits stuck, jumps or drops out when the wiring is gently moved
Unplug the sensor and check its resistance against the manufacturer's specification for the temperature, as the values depend on the model and engine
Check the wiring for continuity, short to earth and short to voltage between the sensor and the control unit using the wiring diagram, and check the reference voltage and earth at the connector
Clear the code after repair and road test to confirm it does not return

How to fix

Replace the oil temperature sensor if its resistance or live data is out of specification
Repair or replace damaged wiring between the sensor and the control unit
Clean or replace corroded or contaminated connector terminals and secure the connector properly
Fix any oil leak that is contaminating the connector or harness, and replace the oil-soaked connector or harness section if needed
Investigate and repair the control unit supply or earth fault, or the control unit itself, only once the sensor and wiring are proven good

Can I keep driving?

Low severity

The car can usually be driven short term as this is typically a monitoring fault, but book it in soon. If the oil temperature display reads very high, a warning appears or the car goes into limp mode, stop and check the oil level and condition before continuing.

Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.