Transmission Oil Temperature Sensor Circuit Range/Performance Problem
Transmission oil temperature sensor value is out of range.
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What it means (plain English)
The transmission control module (TCM) is getting a transmission oil temperature reading that it thinks is too high or too low, possibly from a faulty sensor or bad wiring.
What the computer is actually seeing
The TCM expects the transmission oil temperature to be between 70°F and 250°F. If it sees temperatures outside this range or if there's a value that fluctuates wildly, it triggers the fault code.
What a healthy reading looks like
Normal transmission oil temperature should be around 170°F to 210°F when operating; anything above 250°F or below 70°F can indicate issues.
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 transmission fluid level and condition; ensure it's within the recommended range. Decision point: Fluid level OK? If no, top it off and retest. If yes, proceed to step 2.
- 22. Inspect the wiring and connectors to the transmission oil temperature sensor for damage or corrosion. Decision point: Wiring/connector good? If no, repair or replace as necessary and retest. If yes, proceed to step 3.
- 33. Check the resistance of the transmission oil temperature sensor; it should be within manufacturer specifications at various temperatures. Decision point: Resistance within spec? If no, replace the sensor and retest. If yes, proceed to step 4.
- 44. Verify the TCM functionality with a scan tool; check for software updates or resets. Decision point: TCM functional? If no, consider replacing the TCM. If yes, further diagnosis may be needed.
Common causes
- Faulty transmission oil temperature sensor
- Damaged wiring or connectors to the sensor
- Low transmission fluid level or quality
- Faulty TCM software or hardware
Typical repair cost
$$$
Related codes
Frequently asked questions
Is it safe to drive with this code active?
It's advisable to address this code soon as incorrect transmission temperatures can lead to transmission overheating and damage.
Will this code come back after clearing it?
If the underlying issue isn't resolved, the code will likely return after the vehicle resumes operation.
Why does this code sometimes appear with SPN 3740?
Both codes pertain to the transmission control system and can indicate issues with temperature readings affecting transmission function.
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