What it means
Voltage on the engine coolant temperature 5 sensor signal line is below the expected window. Wire shorted to ground or sensor short.
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 sends a temperature-dependent signal to the engine control module. This code sets when the signal voltage is below its expected range, which can happen if the signal wire is shorted to ground or the sensor is internally shorted.
Common causes
Most likely first.
- Signal wire shorted to ground
- Internal sensor short
- 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
- Check freeze-frame data and Sensor 5 live data to see whether the reading is implausibly cold or fixed at an extreme.
- With the ignition off, inspect Sensor 5's connector and harness for rubbed-through insulation, corrosion, moisture, or bent and loose pins.
- Trace the signal wire for contact with ground, paying particular attention to damaged sections near the sensor and harness bends.
- Test the signal circuit for a short to ground and check connector continuity using the manufacturer's procedure.
- If the wiring checks out, test Sensor 5 against the manufacturer's specification and replace it only if it fails.
Common fixes
- Clean and secure corroded or loose Sensor 5 connector terminals.
- Repair a signal wire shorted to ground.
- Replace Sensor 5 if it has an internal short.
- Repair damaged connector pins or harness sections that cause the low signal.
Can I keep driving?
A short trip may be possible if the engine temperature remains normal, but monitor the temperature warning and gauge closely. Avoid driving if the engine overheats or the cooling fan does not operate when needed, because the faulty reading can lead to inadequate cooling.
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.