P0197 on Ford
Engine Oil Temperature Sensor Circuit Low
P0197 on Ford vehicles indicates engine oil temperature sensor circuit low. Au7o has documented this code across 1 Ford model — most commonly on Flex. This code means the engine oil temperature sensor is sending a signal that is too low, below its valid range. This sensor measures the temperature of the engine oil, which the computer can use for cold-start fueling, oil-life calculations, and protecting the engine. A low-voltage reading usually points to an electrical fault such as a short to ground or a wiring problem rather than genuinely cold oil. It typically doesn't cause major drivability issues but can affect oil-life monitoring and protection strategies. Typical repair costs on Ford range from $1,500 to $7,000, depending on the specific model and root cause.
Common Causes of P0197
- •Faulty engine oil temperature sensor
- •Short to ground in the sensor signal wire
- •Corroded or loose sensor connector
- •Damaged wiring harness near the sensor
- •Bad ground or reference voltage to the sensor
- •Coolant/oil contamination at the connector
- •Faulty PCM (less common)
P0197 on Ford by Model
Ford Flex(1 issue)
- Internal Water Pump Failure Causes Coolant-Oil Mixing and Catastrophic Engine Damage2009-2019
The 3.5L Duratec and 3.5L EcoBoost V6 engines in the Ford Flex have a critical design flaw: the water pump is driven by the timing chain and mounted internally inside the engine. When the water pump seal fails, coolant leaks directly into the engine oil, creating a milky sludge that destroys engine bearings in a matter of miles. Because the pump is internal, there is no external leak to warn the owner — the first symptom is often catastrophic engine failure. This is one of the most expensive and common failures on high-mileage Flex vehicles, with repair quotes ranging from $5,000 to $7,000+ for engine replacement.
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View P0197 across all makes →Frequently Asked Questions
What does P0197 mean on Ford?▼
P0197 stands for "Engine Oil Temperature Sensor Circuit Low." This code means the engine oil temperature sensor is sending a signal that is too low, below its valid range. This sensor measures the temperature of the engine oil, which the computer can use for cold-start fueling, oil-life calculations, and protecting the engine. A low-voltage reading usually points to an electrical fault such as a short to ground or a wiring problem rather than genuinely cold oil. It typically doesn't cause major drivability issues but can affect oil-life monitoring and protection strategies. On Ford specifically, this code is documented across 1 model.
What causes P0197 on Ford vehicles?▼
Common causes on Ford: Faulty engine oil temperature sensor, Short to ground in the sensor signal wire, Corroded or loose sensor connector, Damaged wiring harness near the sensor, Bad ground or reference voltage to the sensor. Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix P0197 on a Ford?▼
Repair costs on Ford range from $1,500 to $7,000, depending on the specific model and root cause.
Which Ford models have P0197 documented?▼
Au7o has documented P0197 on 1 Ford model: Flex.