Temperature Sensor Signal Erratic, Intermittent, or Incorrect
The engine control module is receiving erratic signals from the 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 temperature sensor that checks how hot the engine coolant is sending mixed signals—it might not be working right, which affects the engine’s performance.
What the computer is actually seeing
The ECM reads the temperature signal as fluctuating rapidly or outside normal parameters, typically showing values that can jump from 80°C to 120°C in milliseconds.
What a healthy reading looks like
Normal coolant temperature readings should be between 85°C and 105°C under operating conditions, varying slightly with the ambient 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. Start with a visual inspection of the temperature sensor wiring and connectors for damage or corrosion. Decision: If found damaged, repair it; if not, move to the next step.
- 22. Using a multimeter, check the resistance of the temperature sensor at room temperature (should be around 2,500 to 3,000 ohms). Decision: If out of range, replace the sensor; if within range, proceed.
- 33. Clear the fault code and monitor the live data while the engine is running to see if the coolant temperature fluctuates erratically. Decision: If erratic, replace the temperature sensor; if stable, check the ECM for updates or issues.
Common causes
- Faulty temperature sensor
- Wiring issues or connectors corrosion
- ECM software glitches
- Coolant leaks affecting sensor readings
Typical repair cost
$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
It's moderate severity; you can drive but should fix it soon to avoid performance issues.
Will this code come back after clearing?
If the underlying issue isn't fixed, yes, the code will likely return.
Why does this code show up sometimes with SPN 0694?
They both relate to the temperature sensor but may indicate different issues, like signal strength vs. signal accuracy.
Working a real vehicle right now?
Let DiagCoach walk you through it live with your specific symptoms, vehicle, and what you've already checked.
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