Engine Coolant Temperature Sensor 2 Voltage Low
Engine coolant temperature sensor is reading too low of a voltage.
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What it means (plain English)
The engine coolant temperature sensor 2 is not sending a proper voltage signal to the engine control module, indicating that the engine is cooler than it actually is.
What the computer is actually seeing
Engine coolant temperature should typically be between 185°F and 220°F while running. If the sensor reads less than 0.1V or more than 5V for an extended period, the code is triggered.
What a healthy reading looks like
Normal voltage range is 0.1V to 4.5V when the engine is within normal operating temperature.
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.
- 11. Check coolant level; top off if low. Decision: Is coolant level okay? Yes = go to step 2; No = refill coolant and retest.
- 22. Inspect wiring and connector to Engine Coolant Temperature Sensor 2 for damage. Decision: Any damage found? Yes = repair or replace; No = go to step 3.
- 33. Measure voltage at the Engine Coolant Temperature Sensor 2 connector with the engine at operating temperature. Decision: Is voltage within 0.1V to 4.5V range? Yes = go to step 4; No = replace sensor.
- 44. Check for any ECM updates or technical service bulletins (TSBs) related to this code. Decision: Any TSBs? Yes = apply update or fix; No = if all else is good, consider ECM replacement.
Common causes
- Faulty Engine Coolant Temperature Sensor 2
- Damaged wiring or connectors between the sensor and ECM
- Faulty Engine Control Module (ECM)
- Insufficient coolant level causing incorrect readings
Typical repair cost
$$-$$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
Moderate severity means you can drive, but it'll affect engine performance and fuel efficiency.
Will the code come back after I fix it?
If the underlying issue is resolved, the code typically will not return.
Why does this code pair with others like SPN 111?
Codes for coolant temperature often trigger with related sensors to indicate consistent temperature regulation problems.
Working a real vehicle right now?
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