What it means
The output shaft speed sensor circuit is not providing a valid direction signal.
At a glance
- Usually lights the check-engine light
How it works
The output shaft speed sensor reports how fast the transmission output shaft turns and, on systems with a direction channel, which way it is turning. This code sets when the TCM cannot obtain a valid direction signal from that sensor circuit, such as from a broken direction-channel wire or failed sensor element.
Common causes
Most likely first.
- Open direction-channel wire
- Failed quadrature sensor element
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 transmission codes to see whether the direction signal failed during forward or reverse operation and whether output speed data was also lost.
- Inspect the output shaft speed sensor connector and harness for damage, corrosion, loose terminals, or a broken direction-channel wire.
- Check live output shaft speed and direction data while safely commanding forward and reverse, if the scan tool provides those values.
- Test the direction-channel wiring for continuity and shorts using the vehicle wiring diagram and manufacturer's procedure.
- Test the output shaft speed sensor, including its direction-sensing element, according to the manufacturer's procedure.
- If the sensor and wiring pass, check the tone wheel or other target and TCM input circuit as directed by the manufacturer's diagnostic procedure.
Common fixes
- Repair an open or damaged direction-channel wire.
- Clean and secure the output shaft speed sensor connector or repair its terminals.
- Replace the output shaft speed sensor if its direction element fails testing.
- Repair a damaged sensor target or TCM input circuit if confirmed by testing.
Can I keep driving?
Drive cautiously only if shifts and speed display remain predictable; avoid high speeds and stop if the transmission shifts erratically or enters limp mode. The TCM may lose information needed for proper shift control, increasing the risk of an unexpected shift or further transmission strain.
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.