Cooling

P01E6 — Engine Coolant Temperature Sensor 3 Circuit High

Severity: medium Drive with care, to a shop

What P01E6 means

The engine control unit detected a voltage from coolant temperature sensor 3 that is higher than expected. This usually points to an open circuit, a poor connector contact or a failed sensor. The sensor is a thermistor whose resistance changes with temperature, and the control unit reads that as a voltage. A voltage that is too high looks like a very cold engine or a missing signal.

Symptoms

  • Check engine light is on
  • Temperature gauge jumps or reads wrong
  • Hard starting or rough running when cold
  • Higher fuel consumption
  • Cooling fan runs constantly or at the wrong time
  • False or real overheating warnings

Possible causes

  1. Failed coolant temperature sensor 3
  2. Open circuit in the sensor signal or ground wire
  3. Corroded or loose connector terminals
  4. Signal wire shorted to voltage
  5. Rarely, a control unit fault or software issue

How to diagnose

  1. Read codes and freeze frame data, clear the code and see if it returns
  2. Compare sensor 3 reading on a scan tool with other temperature sensors on a cold engine
  3. Inspect the connector and harness for corrosion, damage or chafing
  4. Unplug the sensor and check reference voltage and ground on the harness side per the wiring diagram
  5. Measure sensor resistance and compare it to the spec at a known temperature
  6. Test the signal wire for opens and shorts to voltage
  7. Swap in a known good sensor and confirm plausible readings
  8. If all is fine, check the control unit and for software updates

Common fixes

  • Repair the sensor wiring or connector
  • Replace coolant temperature sensor 3
  • Reflash the control unit software
  • Replace the control unit if confirmed faulty

Questions and answers

What does P01E6 mean?

The control unit sees a too-high signal from coolant temperature sensor 3. The wiring or the sensor itself is the most common cause.

Can I drive with P01E6?

Briefly, yes, but keep an eye on engine temperature. If the gauge or fan acts oddly, stop and check the cooling system.

Will replacing the sensor fix it?

Not always. Check the connector and wires first, since an open circuit or bad contact sets the same code and a new sensor won't help.

This is general information about the code. The meaning can differ between makes and models: a scan tool and the repair manual for your car will show the exact cause.