P2185Generic code

P2185 Code: Engine Coolant Temperature Sensor 2 Circuit High

The P2185 code means the signal from coolant temperature sensor 2 is above its maximum value. The main effect is that the cooling fan may run all the time and temperature control becomes less precise. You can drive with caution while you watch the temperature gauge.

Severity
Medium
Can I keep driving?
Yes, but with caution
Estimated cost
$20 to $150
Difficulty
Medium
System
Idle and Speed Control
Applies to
All OBD2 vehicles

Updated Reviewed by Renzo Chacca

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What the P2185 code means

Some engines have two coolant temperature sensors: one at the engine outlet and another at the radiator or somewhere else in the cooling circuit. With both, the computer controls the cooling fan and the electronic thermostat, and it can detect cooling system faults.

The sensor changes its resistance with temperature, and the computer measures the resulting voltage. A high signal is usually caused by an open circuit or an interrupted ground.

It is an NTC thermistor, which means its resistance drops as the temperature rises. A sensor guide shows how to test one.

To confirm it, measure the continuity of each wire between the component connector and the computer connector with the key off. It should be less than 1 ohm, and an infinite reading means the wire is open. If the wiring is good, measure the component itself: infinite resistance confirms it is open inside.

P2185 code symptoms

  • Check engine light on.
  • The cooling fan may run all the time, and temperature control becomes less precise.

Likely causes of the P2185 code

  1. Loose or broken connector. The most common cause.
  2. Cut signal or ground wire. The signal rises all the way to the reference voltage.
  3. Sensor open inside with infinite resistance.
  4. Short to 5 V or 12 V from rubbing against another wire in the harness.

How to diagnose the P2185 code step by step

  1. Read the sensor value on the scan tool and compare it with what you expect.
  2. Inspect the connector for corrosion, water or loose pins.
  3. Check power and ground with the key on: correct reference voltage and less than 0.1 V drop on the ground.
  4. Measure the signal with the connector plugged in and see whether it changes with the conditions.
  5. Do a wiggle test on the wiring with the scan tool in graph mode.
  6. Check the continuity of each wire to the computer (less than 1 ohm).

How to fix the P2185 code

  • Repair the connector or the wiring.
  • Replace the sensor if the tests confirm it is bad.
  • Correct the real condition if there is one.
  • Clear the codes and verify with a road test.

Clear the P2185 code and keep an eye on the temperature gauge during the road test. If it climbs above normal, stop the vehicle and let the engine cool down.

Technical reference data

  • Approximate resistance: 2 to 3 kilohms at 68 °F (20 °C) and 200 to 300 ohms at 194 °F (90 °C).
  • Signal: about 3 to 4 V cold and 0.5 to 1 V hot.
  • These are reference values only: check the manufacturer data for your vehicle.

Brand-specific notes

The P2185 code is common on engines with an electronic thermostat and on engines with a sensor mounted in the radiator.

P2185 on BMW

Frequent on BMW engines with an electronic thermostat.

P2185 on Volkswagen

Frequent on Volkswagen engines with an electronic thermostat.

P2185 on Ford

Seen on several Ford engines that have the sensor in the radiator.

P2185 on GM

Seen on several GM engines that have the sensor in the radiator.

Frequently asked questions about P2185

Can I drive with a P2185 code?
Yes, while watching the temperature gauge. If it climbs above normal, pull over and stop.
Does the sensor have to be replaced?
Only if the tests confirm it. The connector and the wiring fail just as often as the sensor.
What does coolant temperature sensor 2 do?
Some engines have two coolant temperature sensors: one at the engine outlet and another at the radiator or elsewhere in the circuit. With both, the computer controls the fan and the electronic thermostat and can spot cooling system faults.
How much does it cost to fix P2185?
Roughly $20 to $150. A connector or wire repair sits at the low end, and a new sensor with labor is closer to the top.
What does the P2185 code mean?
It is a generic OBD2 code that means the signal from engine coolant temperature sensor 2 is above its maximum. It usually points to an open circuit or an interrupted ground.
Will a P2185 code clear itself?
If the connection was only interrupted for a moment, the light can go out after several drive cycles. A loose connector or a cut wire will bring it back, so find the cause.
What is the most common cause of P2185?
A loose or broken connector. After that, look for a cut signal or ground wire.

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