P0118 on Volkswagen
Engine Coolant Temperature Sensor Circuit High
P0118 on Volkswagen vehicles indicates engine coolant temperature sensor circuit high. Au7o has documented this code across 2 Volkswagen models — most commonly on Golf R, New Beetle. 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 Volkswagen range from $30 to $300, 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 Volkswagen by Model
Volkswagen Golf R(1 issue)
- Engine Coolant Temperature Sensor / Inaccurate Temp Gauge2015-2021
Separate from the well-known water-pump/thermostat-housing leak, MK7-platform Golf R owners report failures of the engine coolant temperature (ECT) sensor and a notably unreliable dashboard temperature gauge. The gauge tends to sit pinned at ~90C and gives little warning before overheating, so coolant loss or a failing sensor can let the engine run dangerously hot without alerting the driver. A faulty ECT sensor also causes erratic readings, false overheat warnings, poor cold-start fueling/economy, and a check engine light. VW updated early sensor revisions.
Volkswagen New Beetle(1 issue)
- Engine Coolant Temperature Sensor (G62) Failure1998-2006
The early black-topped coolant temperature sensor (G62, often on the coolant flange below the upper radiator hose) is a well-known weak point on the 2.0 8V and 1.8T New Beetle. The plastic sensor and its flange crack or the sensor sends erratic readings, causing the temperature gauge to swing or read falsely hot/cold, hard cold starts and rich/lean running, and a check-engine light. The original black sensor was superseded by an updated green sensor. Because the ECU uses this signal for fueling and fan control, a failed sensor can mimic a thermostat or head-gasket problem and trigger unnecessary repairs.
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View P0118 across all makes →Frequently Asked Questions
What does P0118 mean on Volkswagen?▼
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 Volkswagen specifically, this code is documented across 2 models.
What causes P0118 on Volkswagen vehicles?▼
Common causes on Volkswagen: 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 Volkswagen?▼
Repair costs on Volkswagen range from $30 to $300, depending on the specific model and root cause.
Which Volkswagen models have P0118 documented?▼
Au7o has documented P0118 on 2 Volkswagen models: Golf R, New Beetle.