P0118 on Ford
Engine Coolant Temperature Sensor Circuit High
P0118 on Ford vehicles indicates engine coolant temperature sensor circuit high. Au7o has documented this code across 1 Ford model — most commonly on Flex. P0118 indicates the engine coolant temperature (ECT) sensor circuit is reading abnormally high voltage, which the computer interprets as an implausibly cold coolant temperature. The ECT sensor changes resistance with temperature and tells the PCM how hot the engine is so it can manage fuel, the cooling fans, and the gauge. High voltage on this circuit usually points to an open circuit or a sensor reporting an unrealistically low temperature. The car may run rich, struggle to enter closed-loop operation, idle poorly, or show an inaccurate temperature gauge. Typical repair costs on Ford range from $1,500 to $7,000, depending on the specific model and root cause.
Common Causes of P0118
- •Faulty (open) engine coolant temperature sensor
- •Open or broken wire in the ECT signal circuit
- •Loose, corroded, or disconnected sensor connector
- •Poor ground or open in the sensor return circuit
- •Damaged wiring harness near the sensor
- •Corrosion in the connector terminals
- •Failed PCM input (rare)
P0118 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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What does P0118 mean on Ford?▼
P0118 stands for "Engine Coolant Temperature Sensor Circuit High." P0118 indicates the engine coolant temperature (ECT) sensor circuit is reading abnormally high voltage, which the computer interprets as an implausibly cold coolant temperature. The ECT sensor changes resistance with temperature and tells the PCM how hot the engine is so it can manage fuel, the cooling fans, and the gauge. High voltage on this circuit usually points to an open circuit or a sensor reporting an unrealistically low temperature. The car may run rich, struggle to enter closed-loop operation, idle poorly, or show an inaccurate temperature gauge. On Ford specifically, this code is documented across 1 model.
What causes P0118 on Ford vehicles?▼
Common causes on Ford: Faulty (open) engine coolant temperature sensor, Open or broken wire in the ECT signal circuit, Loose, corroded, or disconnected sensor connector, Poor ground or open in the sensor return circuit, Damaged wiring harness near the sensor. Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix P0118 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 P0118 documented?▼
Au7o has documented P0118 on 1 Ford model: Flex.