Transmission Fluid Temperature Sensor Fault
Indicates an issue with the transmission fluid 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 transmission fluid temperature sensor measures the temperature of the fluid; if it fails, the system can't tell if the fluid is too hot or too cold, which can lead to shifting problems.
What the computer is actually seeing
The engine control module (ECM) expects a voltage signal from the temperature sensor typically between 0.5V and 4.5V corresponding to fluid temps from -40°F to 257°F. If it sees a voltage outside this range or an open/short circuit, it triggers this code.
What a healthy reading looks like
Transmission fluid temperature should be between 175°F and 220°F during normal operation; sensor voltage should correlate with this temperature range.
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 transmission fluid level. Add fluid if low. Decision point: Are fluid levels correct? YES: Go to step 2. NO: Fill to specified level and retest.
- 22. Inspect wiring and connector at the transmission fluid temperature sensor for damage or corrosion. Decision point: Is the wiring intact? YES: Go to step 3. NO: Repair or replace faulty wiring/connectors and retest.
- 33. Measure the voltage at the sensor connector with the ignition on (engine off). Expected values: 0.5V to 4.5V. Decision point: Is voltage within this range? YES: Replace the transmission fluid temperature sensor. NO: Check for shorts/opens in the wiring harness.
Common causes
- Faulty transmission fluid temperature sensor
- Wiring issues or connector problems
- Faulty transmission control module (TCM)
- Low transmission fluid level or contamination
Typical repair cost
$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
It's not ideal; shifting may be affected but you can drive it short distances. Fix soon.
Will this code come back after clearing it?
If the underlying problem isn't resolved, the code will likely reappear.
Why is it paired with SPN 0709?
Both codes relate to transmission temperature sensor faults, indicating possible sensor or wiring issues.
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