Engine Coolant Temperature Sensor 2
Issue with the second engine coolant temperature sensor.
Heads up: this code wasn't in our hand-written library yet, so DiagCoach AI built this page on the fly. Double-check critical specs against service info before condemning parts.
What it means (plain English)
The second coolant temperature sensor is reporting a value that’s out of the normal range, meaning the engine computer might think the engine is running hotter or cooler than it actually is.
What the computer is actually seeing
The engine control module (ECM) expects the second coolant temperature sensor to produce a voltage signal between 0.5V and 4.5V, corresponding to temperatures between approximately -40°F and 260°F. If the signal is outside this range, or the sensor is unresponsive, it triggers this code.
What a healthy reading looks like
Expected voltage should be between 0.5V (at -40°F) and 4.5V (at 260°F).
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 vehicle's coolant level and top it off if low. Confirm there are no leaks.
- 2Inspect wiring and connectors for damage or corrosion between the sensor and the ECM.
- 3Using a multimeter, measure the voltage at the second coolant temperature sensor connector while the engine is running. Expect 0.5V to 4.5V based on engine temperature. If voltage is out of range, replace the sensor.
- 4If voltage is normal, monitor temperature data with a diagnostic scanner. If temperatures are erratic or out of range, suspect a wiring issue or ECM failure.
Common causes
- Wiring issue (frayed, shorted, or loose connections)
- Faulty second coolant temperature sensor
- Corroded connectors
- Coolant level low or contamination
Typical repair cost
$$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
While it may be drivable, the engine may run inefficiently or risk overheating. Fix it soon.
Will this code come back after repair?
If the underlying issue is fixed, it should not return. Make sure connections are solid.
Why does this code pair with other SPNs?
Codes can trigger together if they relate to the same system, like temperature monitoring, or if one issue causes multiple sensors to fail.
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