P2185: Engine Coolant Temperature Sensor 2 Circuit High

P2185 is the high end of the sensor 2 circuit check. With an NTC thermistor a high signal stands for extreme cold, so the usual reason is an open circuit: a broken wire, an unplugged or corroded connector, or a sensor with an interrupted element; a short to voltage is rarer. GM (19OBDG03D) watches for a resistance in the order of 300 kOhm, the value at -60 °C, after 10 s of engine running or above -20 °C intake air, 5 s within 6 s, Type B. VW sets it at below -43 °C on the 2014 CC and above 4.92 V or 4.94 V on the Touareg. Audi issued a 2025 bulletin for the A4 and A5 family on P2185 at the radiator outlet sender G83. In bulletin 21-NA-149 GM traces it to a chafed harness. Low and erratic signals are P2184 and P2186.

Medium severity. Can I keep driving?Watch the temperature gauge. If it climbs or a warning appears, stop the car in a safe place and turn off the engine: overheating can cause serious damage.

Symptoms

Check engine light
Fans run permanently as a safety measure
Low coolant or temperature warning without a real cause on some models

Most likely causes

Connector at sensor 2 unplugged, loose or corroded
Signal or ground wire of sensor 2 broken
Sensor element interrupted
Signal wire shorted to a voltage source

What to check, in order

Start with the simplest. You can tick off each step.

With the engine cold, check the coolant level; never do this when the system is hot
Check the sensor's ground and make sure the signal wire is not receiving voltage from another circuit.
Check the actual temperature in live data
Make sure the fan comes on when it should
Check the thermostat and connector
Measure the sensor and replace it if its readings do not make sense

Good to know

Repair difficulty: easy
It affects emissions.

What each character of P2185 means

P: Powertrain: engine and transmission
2: Generic code: same on every make
1: Air and fuel
85: Specific fault in that system

Frequently asked questions

Can I keep driving with code P2185?

Watch the temperature gauge. If it climbs or a warning appears, stop the car in a safe place and turn off the engine: overheating can cause serious damage.

What causes code P2185?

The most common causes are: connector at sensor 2 unplugged, loose or corroded; signal or ground wire of sensor 2 broken; sensor element interrupted.

Related codes

Sources

Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.