P0198 Oil temperature sensor reporting a voltage that is too high

Engine oil temperature sensor high input

Monitor

TroubleCodes.net says this code often brings no noticeable drivability problem, so it is usually a sensor-circuit fault rather than an urgent one.

It gets more serious if:

  • Inspect soon: Inspect soon if the temperature gauge climbs, an oil or temperature warning shows, or the engine runs poorly alongside the light, because the listed symptoms include possible overheating and low oil indicators.

Source: how we rate severity

P0198 in short

P0198 means the engine computer sees a voltage that is too high from the engine oil temperature sensor circuit. Common causes are a failed sensor, a wire shorted to a power source, or an open circuit. It often causes no obvious drivability problem, but check the temperature gauge.

The oil temperature sensor is a two-wire thermistor fed 5 volts by the computer. The computer reads the voltage that results as its resistance changes with temperature.

P0198 is set when that voltage is abnormally high. TroubleCodes.net lists a faulty sensor, wiring shorted to positive, a defective alternator, stray voltage from other circuits and a thermostat fault.

The Delaware DMV generic code list gives the same title, engine oil temperature sensor high.

Most likely causes

These are general causes for this code across vehicles. None is specific to one make or model.

  1. Failed oil temperature sensor

    Common general cause
    Why it ranks here
    TroubleCodes.net lists a faulty sensor first among the causes.
    What would change this
    Rises if the sensor reading is far off the chart for its temperature. Falls if the circuit tests faulty first.

  2. Wiring shorted to a positive voltage

    Common general cause
    Why it ranks here
    TroubleCodes.net names wiring shorted to positive as a cause.
    What would change this
    Rises if the wire shows damage or unwanted voltage. Falls if wiring tests clean.

  3. Thermostat fault affecting oil or engine temperature

    Possible — needs testing
    Why it ranks here
    TroubleCodes.net lists a thermostat malfunction among the causes.
    What would change this
    Rises if the engine runs too hot or too cold. Falls if engine temperature is normal.
    How to test the thermostat

What to test first

Start at step 1. Each result tells you what it means and where to go next.

  1. Inspect the oil temperature sensor connector and wiring for damage, chafing or contact with other wiring.

    Low riskTool: visual inspection

  2. Have the sensor circuit checked for the 5-volt reference, the sensor output voltage against the temperature chart, and wiring continuity.

    Best left to a shopTool: multimeter, scan tool

    Warning:Back-probing live connectors can short a circuit and damage the computer. Let a shop do it.

Symptoms

  • Check engine light
  • Often no noticeable drivability problem
  • Possible temperature or low oil level warning Gets more serious: stop and have it checked.

How to fix

  1. With the engine off and cool, check the oil temperature sensor connector and wiring for corrosion, bent pins or damage.

  2. Have the sensor circuit tested against the manufacturer's voltage or resistance chart before replacing the sensor.

Parts and cost context

  • Engine control module (ECM / PCM):The engine computer is a rare cause. Confirm with circuit tests first. Labour varies; get a quote.

Labor varies by vehicle and shop; get a quote before you approve a repair.

Compare used part prices on PartPriceGuide

On your vehicle

Jeep

  • 2021 · Grand Cherokee

    Supported by vehicle data

    Jeep bulletin S2108000042 covers a MIL on with P0198, oil temperature sensor circuit high, on the 2021 Grand Cherokee. Whether it is still current is not verified.

  • S2108000042Status unverified

    MIL on, DTC P0198 oil temperature sensor circuit high

    2021grand-cherokee · issued · NHTSA 10188747

    Jeep bulletin whose summary only states the complaint: MIL on with DTC P0198, oil temperature sensor circuit high. The summary does not give the repair.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

Volkswagen

  • 2016–2018 · Atlas

    Supported by vehicle data

    Volkswagen bulletin VIN-4-A-PIN-2018 lists a coolant leak at the coolant pump with the yellow oil warning light on and faults including P0198 on this model range (2016-2018). The bulletin also lists unrelated items. Whether it is still current is not verified.

  • 2016–2018 · Golf

    Supported by vehicle data

    Volkswagen bulletin VIN-4-A-PIN-2018 lists a coolant leak at the coolant pump with the yellow oil warning light on and faults including P0198 on this model range (2016-2018). The bulletin also lists unrelated items. Whether it is still current is not verified.

  • 2016–2018 · GTI

    Supported by vehicle data

    Volkswagen bulletin VIN-4-A-PIN-2018 lists a coolant leak at the coolant pump with the yellow oil warning light on and faults including P0198 on this model range (2016-2018). The bulletin also lists unrelated items. Whether it is still current is not verified.

  • 2016–2018 · Jetta

    Supported by vehicle data

    Volkswagen bulletin VIN-4-A-PIN-2018 lists a coolant leak at the coolant pump with the yellow oil warning light on and faults including P0198 on this model range (2016-2018). The bulletin also lists unrelated items. Whether it is still current is not verified.

  • 2016–2018 · Passat

    Supported by vehicle data

    Volkswagen bulletin VIN-4-A-PIN-2018 lists a coolant leak at the coolant pump with the yellow oil warning light on and faults including P0198 on this model range (2016-2018). The bulletin also lists unrelated items. Whether it is still current is not verified.

  • VIN-4-A-PIN-2018Status unverified

    Coolant pump leak with yellow oil warning light and faults P0196 or P0198

    2016–2018atlas, beetle, golf, golf-r, gti, jetta, passat, tiguan · issued · NHTSA 10150841

    Volkswagen bulletin that lists several unrelated items. One item is a coolant leak at the coolant pump with the yellow oil warning light on and faults P0196, P0198, B104129 or B104135. The summary does not give the repair.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

  • P0197Oil temperature sensor reporting a voltage that is too low

    Same system Common general cause

    P0197 is the low-input code for the same sensor.

  • P0199Oil temperature sensor signal dropping in and out

    Same system Common general cause

    P0199 is the intermittent code for the same sensor.

All Ignition and engine position sensors codes

Sources and review

  1. P0198 trouble code explanation — TroubleCodes.net
  2. S2108000042: MIL on, DTC P0198 oil temperature sensor circuit high — Jeep
  3. VIN-4-A-PIN-2018: Coolant pump leak with yellow oil warning light and faults P0196 or P0198 — Volkswagen
  4. On-Board Diagnostic Trouble Codes (generic code title list) — Delaware Division of Motor Vehicles
Last reviewed
Written by
Saurabh K.
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