Cooling

P01E3 — Engine Coolant Temperature Sensor 3 Circuit Fault

Severity: medium Drive with care, to a shop

What P01E3 means

P01E3 means the engine control module sees an incorrect or implausible signal in the circuit of engine coolant temperature sensor 3. The sensor is a thermistor whose resistance changes with temperature, and the module reads it as a voltage. Which part of the cooling system sensor 3 monitors depends on the manufacturer, so check the vehicle's service information.

Symptoms

  • Check Engine Light on
  • Temperature gauge reads wrong or jumps around
  • Worse fuel economy
  • Reduced power or rough running
  • Cooling fan runs constantly or at the wrong time
  • Hard starting when hot or cold

Possible causes

  1. Failed coolant temperature sensor 3
  2. Damaged or corroded wiring or connector in the sensor circuit
  3. Open circuit in the sensor wiring
  4. Short to ground or to voltage in the circuit
  5. Low coolant level or an air pocket around the sensor
  6. PCM failure (uncommon)

How to diagnose

  1. Scan all codes and freeze frame data, and look for other cooling system codes.
  2. Check coolant level and condition, and bleed air from the system if needed.
  3. Inspect the sensor, connector and harness for damage, moisture and corrosion.
  4. Compare the scan tool reading with actual temperature from a thermometer, both cold and warm.
  5. Measure the sensor resistance and compare it with the manufacturer's table.
  6. Check reference voltage, ground and wire continuity to the PCM with a multimeter.
  7. If the wiring and sensor are good, test the PCM and check for software updates.

Common fixes

  • Replace coolant temperature sensor 3
  • Repair the wiring or replace the damaged connector
  • Top up coolant and bleed the system
  • Reflash or replace the PCM if confirmed faulty

Questions and answers

Can I drive with P01E3?

Briefly, yes, but watch the engine temperature. Wrong sensor data can cause overheating or a bad fuel mixture, so don't put the repair off.

What most often causes P01E3?

Wiring and connector problems such as opens, shorts or corroded pins are most common, followed by the sensor itself.

Is clearing the code enough?

No. If the cause remains, the code will return. Find the fault in the circuit or sensor first.

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.