Transmission Oil Temperature
Indicates a problem with the transmission oil 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 computer monitors the temperature of the transmission fluid to ensure proper operation. If the fluid gets too hot, it can cause shifting problems and damage the transmission.
What the computer is actually seeing
The transmission control module (TCM) expects a transmission oil temperature reading between 75°F and 200°F, depending on operating conditions. If the sensor reports below 30°F or above 250°F, the TCM triggers this fault code.
What a healthy reading looks like
Transmission oil temperature should range from 75°F to 200°F under normal operation.
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. Fill or change fluid if necessary. DECISION: If fluid level is low, refill and retest.
- 22. Inspect wiring and connectors to the transmission oil temperature sensor for damage or corrosion. DECISION: Repair any damaged wiring or connectors, then retest.
- 33. Use a scan tool to read the actual transmission oil temperature. Compare this value with the expected range (75°F to 200°F). DECISION: If the reading is outside this range, proceed to the next step.
- 44. Replace the transmission oil temperature sensor if the wiring is good, and the readings are still incorrect. DECISION: After replacing, retest the system.
Common causes
- Faulty transmission oil temperature sensor
- Wiring issues or poor connections
- Low transmission fluid level
- Faulty transmission control module (TCM)
Typical repair cost
$$ 100 - $400
Related codes
Frequently asked questions
Is it safe to drive with this code?
It's moderate severity; driving is possible but may cause shifting issues or further damage.
Will this code come back after clearing?
If the underlying issue isn't fixed, yes, it will return.
Why might this code show with SPN 179?
Both codes relate to transmission temperature and can indicate similar issues in sensor readings.
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