Engine Coolant Temperature Sensor 2 Circuit High
The P2185 code indicates that the Engine Control Module (ECM) has detected a voltage signal from the Engine Coolant Temperature (ECT) sensor 2 that is higher than the expected range, typically above 4.9 volts. This sensor is usually located in the cylinder head or thermostat housing and provides coolant temperature data for fuel management and cooling fan control. A high voltage reading suggests an open circuit, poor connection, or a faulty sensor, which can lead to incorrect fuel mixture and engine performance issues.
01. Most Common Causes
- Faulty Engine Coolant Temperature Sensor 2
- Open or shorted wiring in the sensor circuit
- Poor electrical connection at the sensor or ECM
- Corroded or damaged connector pins
- ECM failure (rare)
02. Symptoms You Will Notice
- Check Engine Light illuminated
- Engine running rich or poor fuel economy
- Hard starting, especially when cold
- Cooling fans running continuously or not at all
- Engine overheating or running cooler than normal
03. Step-by-Step Diagnosis
Step 1: Use an OBD2 scanner to confirm the code and check for related codes (e.g., P2184).
Step 2: Visually inspect the ECT sensor 2 connector and wiring for damage, corrosion, or loose connections.
Step 3: Disconnect the sensor and measure resistance across its terminals; compare to manufacturer specifications (typically 2-10 kΩ at cold engine).
Step 4: With the sensor disconnected, check voltage at the harness connector (should be around 5V reference). If not, check for open/short in wiring to ECM.
Step 5: If voltage is correct and sensor resistance is out of spec, replace the ECT sensor 2.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended to drive long distances as the engine may run rich, causing poor fuel economy and potential damage to the catalytic converter. However, you can drive short distances to a repair shop.
How much does it cost to fix?▼
The cost typically ranges from $50 to $150, including parts (sensor $20-$50) and labor (0.5-1 hour).