Temperature Sensor 1 Fault
Indicates a fault with the temperature sensor 1 circuit.
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 1 is likely malfunctioning, which means the engine control module (ECM) isn't getting the right coolant temperature readings.
What the computer is actually seeing
ECM expects temperature readings from the sensor between -40°C to 120°C (-40°F to 248°F). If readings are outside this range or the sensor is completely unresponsive, a fault code will trigger.
What a healthy reading looks like
Normal operation shows coolant temperature around 80°C to 100°C (176°F to 212°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.
- 11. Check the wiring harness and connectors for damage or corrosion; repair as necessary. Decision Point: Are there any issues? Yes: Fix wiring. No: Proceed to step 2.
- 22. Measure the voltage at the temperature sensor connector with key on (engine off); expect around 5V reference voltage. Decision Point: Is voltage present? Yes: Proceed to step 3. No: Repair reference voltage issue.
- 33. With the engine running, use a scan tool to monitor the temperature reading from the sensor. Decision Point: Is it within -40°C to 120°C? Yes: Consider ECM issue. No: Proceed to step 4.
- 44. Replace the temperature sensor and retest. Decision Point: Does fault return? Yes: Investigate further. No: Repair is complete.
Common causes
- Defective temperature sensor
- Wiring issues (shorts or opens in the circuit)
- Corroded or loose connectors
- ECM malfunction
Typical repair cost
$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
Moderate severity means you should fix it soon, but you can drive short distances. Monitor engine temperature.
Will the code come back after clearing?
If the underlying issue is not resolved, yes, the code will return.
Why does it pair with other SPNs?
Related SPNs usually indicate symptoms of the same underlying issue, often tied to sensor or wiring problems.
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