Faulty engine coolant temperature sensor 3; Damaged or corroded wiring or connector at sensor 3; Open or short circuit in the sensor signal or ground circuit; Coolant leak or low coolant level affecting sensor reading; Failed thermostat causing abnormal temperature behavior; PCM internal fault or software issue (rare)

DTC codes / P01xx · Fuel and air metering / P01E3

P01E3Engine Coolant Temperature Sensor 3 Circuit

Q: What does code P01E3 mean?

Engine Coolant Temperature Sensor 3 Circuit. P01E3 indicates that the powertrain control module (PCM) has detected an abnormal condition on the circuit for engine coolant temperature (ECT) sensor 3, which is a third temperature sensor used on some engines for enhanced monitoring. The PCM compares the sensor signal to expected values and sets this code when the voltage or rationality check falls outside the programmed limits.

P01E3 indicates that the powertrain control module (PCM) has detected an abnormal condition on the circuit for engine coolant temperature (ECT) sensor 3, which is a third temperature sensor used on some engines for enhanced monitoring. The PCM compares the sensor signal to expected values and sets this code when the voltage or rationality check falls outside the programmed limits.

SystemPowertrain

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyIntermediate

AreaFuel and air metering

Symptoms you may notice

Illumination of the check engine light, often with no other noticeable symptoms
Inaccurate or erratic temperature gauge readings on the dashboard
Poor fuel economy or rough running when the engine is cold
Cooling fan running constantly or not engaging at all
Hard starting or stalling when the engine is cold
Reduced engine performance or limp mode in some vehicles

Common causes, most likely first

Faulty engine coolant temperature sensor 3
Damaged or corroded wiring or connector at sensor 3
Open or short circuit in the sensor signal or ground circuit
Coolant leak or low coolant level affecting sensor reading
Failed thermostat causing abnormal temperature behavior
PCM internal fault or software issue (rare)

How to diagnose and fix it

Verify coolant level and condition; top off or replace coolant if needed
Perform a visual inspection of sensor 3 and its wiring for damage or corrosion
Use a scan tool to check live data from sensor 3 and compare with other temperature sensors
Test the sensor resistance with a multimeter and compare to specifications
Check continuity and voltage drop on the signal and ground circuits
Replace sensor 3 if faulty and clear the code
If the code persists, diagnose the PCM and circuit integrity with a professional scan tool

Don't overlook the simple causes first

A low coolant level or air pocket can cause sensor 3 to read incorrectly and set this code, so always check the cooling system before replacing parts.
Sensor 3 is often a redundant sensor used for monitoring; a failure may not affect driveability, leading some to ignore it until other codes appear.
Corroded connectors or chafed wiring near the sensor are common culprits, especially on higher-mileage vehicles.
A faulty thermostat can cause temperature fluctuations that trigger rationality codes for sensor 3 even if the sensor itself is good.
This code is rarely caused by a failed PCM, so avoid replacing the computer until all circuit and sensor tests are complete.

Can I keep driving with P01E3?

You can usually continue driving with this code, but monitor the temperature gauge and avoid heavy loads or long trips until repaired. If the engine overheats or performance degrades, stop driving and seek service.

Tools that help

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Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.