What it means
The ECM detects a generic fault on the engine coolant temperature 5 sensor circuit. Reading cannot be used reliably for control.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
Engine coolant temperature sensor 5 reports coolant temperature to the engine control module. The module monitors this sensor's electrical circuit for a usable reading; this code sets when it detects a circuit fault, though it does not by itself specify whether the signal is low, high, or intermittent.
Common causes
Most likely first.
- Sensor failed
- Wiring or connector fault
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
- Check freeze-frame data and live readings for coolant temperature sensor 5, comparing its value with other engine-temperature data and ambient temperature.
- Locate sensor 5 using vehicle service information and inspect its connector and harness for damage, corrosion, coolant intrusion, or loose terminals.
- Check whether the engine warms normally and whether the cooling fan behavior matches the reported temperature, noting that these symptoms can also have other causes.
- Use the wiring diagram to test sensor 5's signal, reference, and ground circuits for opens, shorts, or poor connections.
- Test sensor 5 against the manufacturer's specification and compare its response with the harness-side circuit to isolate a sensor or wiring fault.
Common fixes
- Clean and secure sensor 5 connector terminals if contact is poor.
- Repair damaged wiring or a poor connection in the sensor 5 circuit.
- Replace sensor 5 if it fails testing.
- Clear the code and confirm the temperature reading changes plausibly as the engine warms.
Can I keep driving?
If the fan does not run when needed or the engine temperature rises, stop driving to avoid overheating and engine damage. If temperature remains normal, limit the trip and watch the gauge or warning lights until sensor 5 is repaired.
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.