Engine Cooling Water Temperature Sensor 2
Indicates a fault with the secondary engine coolant temperature sensor.
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What it means (plain English)
The engine computer gets a bad reading from the second coolant temperature sensor, which could make it think the engine is running too hot or too cold.
What the computer is actually seeing
The engine control module (ECM) expects the secondary coolant temperature sensor to send a voltage signal between 0.5 to 4.5 volts, depending on the coolant temperature of around 70°C to 110°C. If the signal is out of range or missing, it triggers this fault.
What a healthy reading looks like
0.5V (around 0°C) to 4.5V (around 110°C) for the second coolant temperature sensor signal.
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 coolant level; it must be above the minimum mark.
- 2Inspect the wiring and connectors going to the secondary coolant temperature sensor for damage or corrosion.
- 3Using a multimeter, measure the voltage at the secondary coolant temperature sensor: expect between 0.5V to 4.5V with the engine at operating temperature.
- 4If the voltage is out of range, replace the secondary coolant temperature sensor. If the voltage is correct, inspect the wiring back to the ECM for further issues.
Common causes
- Faulty secondary coolant temperature sensor
- Wiring issues (shorts or opens) in the sensor circuit
- Connector corrosion or loose connection
- Coolant level too low
- Faulty engine control module (rare)
Typical repair cost
$$$
Related codes
Frequently asked questions
Is it safe to drive with this code active?
Yes, but fix it soon to prevent possible overheating or poor engine performance.
Will this fault come back after repairs?
If the root cause is properly addressed, it shouldn't return.
Why does this code appear with other codes?
Faulty sensors can cause multiple codes to trigger due to shared circuits or related systems.
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