What it means
A fault has been detected in the circuit for engine coolant temperature sensor 3. The code does not specify the sensor's location or function; these depend on the vehicle.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
Coolant temperature sensor 3 reports temperature information to a control module, which uses it for functions such as fan operation and engine warm-up control. This code sets when the sensor 3 circuit has an electrical fault; the sensor's location and exact role vary by vehicle.
Common causes
Most likely first.
- Failed coolant temperature sensor 3
- Damaged or corroded sensor connector
- Open or shorted wiring
- Fault in the sensor power or ground circuit
Symptoms
- Check engine light on
- Cooling fan runs constantly or not at all
- Cabin heater weak or excessively hot
- Possible long warm-up time or hard cold start
How to diagnose it
- Save freeze-frame data and compare sensor 3 temperature with other available coolant-temperature readings and ambient temperature when the engine is cold.
- Locate coolant temperature sensor 3 using vehicle service information, then inspect its connector and nearby wiring for corrosion, damage, or a loose fit.
- With the ignition off, check the sensor and harness connectors for pushed-back, bent, or contaminated pins.
- Test the sensor 3 signal, supply, and ground circuits for opens or shorts, following the manufacturer's circuit information.
- If the wiring checks out, test the sensor against the manufacturer's specification and replace it only if it fails.
Common fixes
- Reconnect and secure a loose sensor 3 connector.
- Clean corroded connector pins or repair damaged terminals.
- Repair an open or short in the sensor 3 wiring, supply, or ground.
- Replace coolant temperature sensor 3 if it fails testing.
Can I keep driving?
You can usually drive cautiously if the temperature gauge is normal, but watch for overheating because sensor 3 may affect fan control. Stop if the engine overheats or the cooling fan fails to operate when needed.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.