What it means
Voltage on the engine coolant temperature 5 sensor signal line is above the expected window. Wire shorted to B+ or sensor open.
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 provides a temperature signal that the engine control module uses to assess engine temperature. This code sets when its signal voltage is above the expected range, consistent with an open sensor or a signal wire shorted to battery voltage.
Common causes
Most likely first.
- Signal wire shorted to B+
- Open sensor
- Connector pins corroded - high contact resistance
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
- Review freeze-frame data and Sensor 5 live data to check whether its reading is implausibly cold or fixed at an extreme.
- Inspect Sensor 5's connector and harness for an unplugged connection, broken wire, corrosion, moisture, or pushed-back pins.
- Check the signal wire for a short to battery voltage, focusing on damaged insulation and places where it may contact powered wiring.
- Test the signal circuit and connector continuity using the manufacturer's procedure to identify an open or unwanted voltage.
- If the wiring is intact, test Sensor 5 against the manufacturer's specification for an internal open.
Common fixes
- Reconnect and secure a loose Sensor 5 connector.
- Repair an open or damaged signal wire.
- Repair a signal wire shorted to battery voltage.
- Replace Sensor 5 if it is open when tested to the manufacturer's specification.
Can I keep driving?
Use caution and keep any necessary trip short while monitoring the temperature gauge and warning lights. Do not continue if the engine overheats or the cooling fan fails to respond as needed, since the control module may not have a reliable Sensor 5 reading.
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.