P0117 on Ford
Engine Coolant Temperature Sensor Circuit Low
P0117 on Ford vehicles indicates engine coolant temperature sensor circuit low. Au7o has documented this code across 2 Ford models — most commonly on Flex, Windstar. This code means the engine coolant temperature (ECT) sensor is reading too low a voltage, which the computer interprets as an impossibly high coolant temperature. In most cases this is an electrical fault — such as a short to ground in the wiring — rather than the engine actually overheating. The coolant temperature signal affects fuel mixture, cooling fans, and other functions, so a bad reading can cause poor running, hard starting, or fans running constantly. The fault is usually in the sensor or its wiring. Typical repair costs on Ford range from $400 to $7,000, depending on the specific model and root cause.
Common Causes of P0117
- •Faulty engine coolant temperature sensor
- •Short to ground in the sensor signal wire
- •Damaged or corroded wiring/connector at the sensor
- •Coolant contamination affecting the sensor
- •Poor electrical ground
- •Faulty PCM/ECM (less common)
P0117 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.
Ford Windstar(1 issue)
- Intake Manifold Gasket Coolant Leak1999-2003
The 3.8L V6 intake manifold gaskets degrade and allow coolant to leak externally or internally into the engine oil. This is closely related to the head gasket issue and can lead to overheating and engine damage if not addressed.
Looking for P0117 on a different make?
View P0117 across all makes →Frequently Asked Questions
What does P0117 mean on Ford?▼
P0117 stands for "Engine Coolant Temperature Sensor Circuit Low." This code means the engine coolant temperature (ECT) sensor is reading too low a voltage, which the computer interprets as an impossibly high coolant temperature. In most cases this is an electrical fault — such as a short to ground in the wiring — rather than the engine actually overheating. The coolant temperature signal affects fuel mixture, cooling fans, and other functions, so a bad reading can cause poor running, hard starting, or fans running constantly. The fault is usually in the sensor or its wiring. On Ford specifically, this code is documented across 2 models.
What causes P0117 on Ford vehicles?▼
Common causes on Ford: Faulty engine coolant temperature sensor, Short to ground in the sensor signal wire, Damaged or corroded wiring/connector at the sensor, Coolant contamination affecting the sensor, Poor electrical ground. Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix P0117 on a Ford?▼
Repair costs on Ford range from $400 to $7,000, depending on the specific model and root cause.
Which Ford models have P0117 documented?▼
Au7o has documented P0117 on 2 Ford models: Flex, Windstar.