Faulty engine coolant temperature sensor 2; Damaged or corroded wiring or connector at sensor 2; Open or short circuit in the sensor 2 signal or ground circuit; Coolant level low or air pockets in the cooling system affecting sensor readings; Failed thermostat causing abnormal temperature changes that the sensor reports; Corrosion or debris on the sensor tip insulating it from coolant flow; Rarely, a software or calibration issue in the powertrain control module

DTC codes / P21xx · Fuel and air metering / P2182

P2182Engine Coolant Temperature Sensor 2 Circuit

Q: What does code P2182 mean?

Engine Coolant Temperature Sensor 2 Circuit. P2182 indicates that the powertrain control module has detected an implausible or out-of-range signal from the second engine coolant temperature sensor, which is typically located at the radiator outlet or in a separate coolant circuit. The computer compares this signal against expected values and the primary coolant sensor to determine that the circuit is not reporting a believable temperature.

P2182 indicates that the powertrain control module has detected an implausible or out-of-range signal from the second engine coolant temperature sensor, which is typically located at the radiator outlet or in a separate coolant circuit. The computer compares this signal against expected values and the primary coolant sensor to determine that the circuit is not reporting a believable temperature.

SystemPowertrain

Code typeGeneric (all makes)

SeverityLow

Fix difficultyIntermediate

AreaFuel and air metering

Symptoms you may notice

Illumination of the check engine light, often with no other noticeable symptoms
Inaccurate or fluctuating temperature gauge readings on the dashboard
Cooling fans that run constantly or fail to activate when needed
Reduced fuel economy or slightly rough running during warm-up
A message on the driver information display indicating a coolant temperature fault

Common causes, most likely first

Faulty engine coolant temperature sensor 2
Damaged or corroded wiring or connector at sensor 2
Open or short circuit in the sensor 2 signal or ground circuit
Coolant level low or air pockets in the cooling system affecting sensor readings
Failed thermostat causing abnormal temperature changes that the sensor reports
Corrosion or debris on the sensor tip insulating it from coolant flow
Rarely, a software or calibration issue in the powertrain control module

How to diagnose and fix it

Verify coolant level and condition, and pressure-test the cooling system for leaks
Inspect the sensor 2 connector and wiring for corrosion, chafing, or loose pins
Measure the resistance of sensor 2 at known temperatures and compare to specifications
Back-probe the sensor 2 signal circuit to check for a plausible voltage with the key on
Check the sensor 2 ground circuit for excessive resistance to the engine block
Replace the sensor if resistance or voltage tests are out of range, then clear codes and retest
If the circuit tests good, diagnose the thermostat and cooling system operation before condemning the PCM

What the second coolant sensor really does

Many vehicles use sensor 2 primarily for cooling fan control and radiator outlet temperature monitoring, so a fault may not affect the dashboard gauge at all.
A common misdiagnosis is replacing sensor 2 when the real problem is a stuck-open thermostat that prevents the radiator outlet from reaching expected temperatures.
Air trapped in the cooling system after a repair can cause sensor 2 to read erratically and set this code even though the sensor is good.
On some models, sensor 2 shares a ground or reference circuit with other sensors, so a fault elsewhere can corrupt its signal and set P2182.
Clearing the code without verifying live data from both coolant sensors often leads to a quick return of the fault and unnecessary parts swapping.

Can I keep driving with P2182?

The vehicle is generally safe to drive with P2182 because the primary coolant sensor still protects the engine, but avoid heavy loads or long idles until the fault is repaired. If the temperature gauge behaves erratically or the engine overheats, stop driving and address the cooling system immediately.

Tools that help

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Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.