What it means
Output shaft speed sensor signal voltage above the upper limit — short to reference voltage or open signal return.
At a glance
- Usually lights the check-engine light
How it works
The output shaft speed sensor provides a signal the TCM uses to calculate transmission output speed and manage shifts. This code sets when that signal voltage is above the expected upper limit, often because the signal wire is shorted to reference voltage or the return path is open.
Common causes
Most likely first.
- Signal wire shorted to reference voltage
- Connector pins corroded - high contact resistance
- Supply wire pinched against B+ source
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 determine when the high signal occurred and whether output shaft speed data was implausible.
- Inspect the output shaft speed sensor connector and harness for pinched wiring, corrosion, loose terminals, or contact with a reference-voltage or power wire.
- Check live output shaft speed data while the vehicle is safely operated and compare it with other available speed readings.
- Test the signal, reference, and return circuits against the wiring diagram and manufacturer's procedure to locate a short to voltage or open return.
- Test the output shaft speed sensor according to the manufacturer's procedure.
- If the wiring and sensor pass, inspect the sensor target and TCM input circuit for a fault.
Common fixes
- Repair a signal wire shorted to reference voltage or a power source.
- Repair an open return circuit and clean or secure corroded connector terminals.
- Replace the output shaft speed sensor if it fails its specified test.
- Repair a damaged sensor target or TCM input if testing confirms the fault.
Can I keep driving?
Avoid high speeds and towing if the transmission shifts harshly or unpredictably, because the TCM may be acting on an incorrect output speed signal. Stop driving if the transmission slips or loses normal gear control.
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.