Engine Coolant Temperature Sensor 2
Indicates a problem with the second engine coolant temperature sensor.
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What it means (plain English)
The engine has two coolant temperature sensors; this one is malfunctioning, which may cause incorrect temperature readings.
What the computer is actually seeing
The ECM expects voltage from the sensor between 0.5V (cold) and 4.5V (hot). If it reads out of this range or shows no change as temperatures fluctuate, it triggers the fault code.
What a healthy reading looks like
Most coolant temperature sensors should read around 1.0V at 32°F, 1.5V at 140°F, and 4.0V at 260°F. Values should change steadily based on coolant 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 the wiring and connectors leading to the coolant temperature sensor for damage or corrosion. If issues found, repair them before proceeding.
- 22. With the engine running at normal operating temperature, use a multimeter to check the voltage at the sensor connector. Expected voltage should be within 0.5V to 4.5V. If voltage is out of range, replace the sensor.
- 33. If the sensor voltage is good, check the ECM for updates or faults. If no updates or faults in the ECM, ensure that there are no coolant leaks which can affect the sensor's performance.
Common causes
- Faulty coolant temperature sensor
- Wiring/connector issues
- ECM software glitch
- Coolant leaks affecting sensor readings
Typical repair cost
$$$
Related codes
Frequently asked questions
Is it safe to drive with this code active?
It's moderate severity; monitor temperature closely. If overheating occurs, pull over immediately.
Will this code return after fixing?
If the sensor is replaced and wiring is repaired, the code should not return unless there's another issue.
Why is this code related to other SPNs?
These codes often signify related sensor issues or shared wiring problems that can affect multiple sensors.
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