Engine Coolant Temperature Sensor Out of Range
The engine coolant temperature reading is outside the normal range.
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What it means (plain English)
The engine coolant temperature sensor is reporting a temperature that doesn't fit within expected limits — it's either too low or too high, affecting performance.
What the computer is actually seeing
The engine control module (ECM) expects coolant temperature readings between 190°F and 220°F (88°C to 104°C). If it sees readings below 140°F (60°C) or above 260°F (127°C), it triggers this fault code.
What a healthy reading looks like
Normal engine coolant temperature should be between 190°F and 220°F (88°C to 104°C).
Guided diagnostic — the DiagCoach way
Don't just throw parts at it. Walk through these in order — each step tells you whether to keep going or stop and fix what you found.
- 1Check the engine coolant level—ensure it is within normal range.
- 2Inspect wiring and connectors at the coolant temperature sensor for corrosion or damage. Look for loose connections.
- 3Using a multimeter, measure the voltage at the coolant temperature sensor connector. Normal operation should show around 0.5V to 4.5V depending on temperature.
- 4If voltage is normal, use a scan tool to monitor the live data of the coolant temperature while the engine runs. It should match the ambient temperature on a cold start and rise as the engine warms.
- 5If the readings are still out of range, replace the coolant temperature sensor and clear the code. Retest the system.
Common causes
- Faulty coolant temperature sensor
- Wiring issues to the sensor
- Coolant leaks affecting temperature
- Faulty engine thermostat
- Poor engine grounding
Typical repair cost
$$
Related codes
Frequently asked questions
Is it safe to drive with this code active?
It's generally safe to drive short distances, but monitor engine temperature closely and repair soon to avoid overheating.
Will this code come back after clearing?
If the cause is fixed, it shouldn’t return. If unresolved issues remain, it will trigger again.
Why does this code sometimes pair with SPN 0395?
SPN 0395 is often triggered when the temperature sensor fails to send a signal, leading to SPN 0396 being logged as well.
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