What it means
Output shaft speed sensor signal voltage below the lower limit — short to ground or open supply. TCM disables vehicle-speed dependent shift logic and may force limp-home.
At a glance
- Usually lights the check-engine light
How it works
The output shaft speed sensor sends a signal the TCM uses to calculate transmission output speed and support shift control. This code sets when the signal voltage is below the expected lower limit, commonly from a signal wire shorted to ground, a damaged harness, or a poor connector connection.
Common causes
Most likely first.
- Signal wire shorted to ground
- Connector pins corroded - high contact resistance
- Harness chafing through insulation
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 when the low signal occurred and whether output shaft speed dropped to zero or became implausible.
- Inspect the output shaft speed sensor connector and harness for chafing, corrosion, loose pins, or insulation damage that could short the signal to ground.
- Check live output shaft speed data while the vehicle is safely operated, and compare it with other speed readings if available.
- Test sensor supply, signal, and ground circuits using the wiring diagram and manufacturer's procedure to locate a short to ground or open supply.
- Test the output shaft speed sensor itself according to the manufacturer's procedure.
- If the sensor and wiring pass, inspect the sensor target and TCM input circuit for damage or fault.
Common fixes
- Repair chafed or shorted output shaft speed sensor wiring.
- Clean and secure corroded or loose sensor connector terminals.
- Restore a faulty sensor supply or ground circuit.
- Replace the output shaft speed sensor if it fails testing.
- Repair a damaged sensor target or TCM input if confirmed.
Can I keep driving?
Limit driving and avoid high speeds if shifts become harsh, delayed, or unpredictable, because the TCM may lack reliable output speed for shift control. Stop if the transmission slips or enters limp mode, since continued operation can increase transmission wear.
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.