What it means
Modern transmissions can have two or more ATF temperature sensors (sump, cooler return, valve body). After a long key-off soak they should all read approximately the same ambient. The TCM detects an implausible spread between sensors — one of them drifts or is wired wrong.
At a glance
- Usually lights the check-engine light
How it works
Some transmissions use multiple fluid temperature sensors, such as sensors near the sump, cooler return, or valve body. After the vehicle has been off long enough to cool, the TCM compares their readings; this code sets when the readings differ more than expected, suggesting a drifting sensor, wiring problem, or sensors connected in the wrong locations.
Common causes
Most likely first.
- One sensor drifting outside tolerance
- Sensors swapped after service
Symptoms
- Check engine or transmission warning light on
- Harsh, delayed, or missing shifts
- Possible limp mode (locked in one gear)
- Slipping or shuddering during gear changes
How to diagnose it
- Read freeze-frame data and all transmission temperature codes to see which sensor readings disagreed and under what conditions.
- After a long key-off soak, compare all available transmission temperature readings with one another and with ambient conditions using scan-tool live data.
- Inspect each temperature sensor connector and harness for corrosion, damage, loose pins, or signs of recent wiring work.
- Verify that each sensor is connected to the correct location, especially if the transmission or cooler plumbing was recently serviced.
- Test each temperature sensor and its wiring against the manufacturer's procedure to identify a drifting sensor or circuit fault.
- If the sensors and wiring test correctly, check the TCM input and temperature data interpretation using the manufacturer's diagnostic procedure.
Common fixes
- Reconnect sensors to their correct locations if they were swapped during service.
- Repair loose, corroded, or damaged temperature sensor connectors and wiring.
- Replace the temperature sensor that fails its specified test.
- Repair a faulty TCM input circuit if testing confirms the problem.
Can I keep driving?
If shifts are normal, a short gentle trip may be possible, but avoid towing or heavy use until the temperature readings are reliable. Stop if the transmission shifts abnormally or shows signs of overheating, since incorrect temperature data can affect shift and protection strategies.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.