What it means
The ECM detects a circuit intermittent/erratic fault on the gear selection actuator position sensor. Reading cannot be used reliably for control.
At a glance
- Usually lights the check-engine light
- The engine or gearbox may go into limp mode
How it works
The gear selection actuator position sensor reports the actuator's position to the control module. This code sets when that signal jumps, drops out, or changes unpredictably instead of tracking position steadily, often because of a loose connector, unstable ground reference, or vibration-sensitive contact.
Common causes
Most likely first.
- Sensor connector not seated
- Noisy ground reference
- Connector with intermittent contact under vibration
Symptoms
- Check-engine or transmission warning light
- Intermittent or unpredictable gear changes
- Transmission may enter a limited-operation mode
How to diagnose it
- Review freeze-frame data and graph live actuator position while selecting gears, looking for dropouts or sudden jumps.
- Inspect and reseat the gear selection sensor connector, checking for corrosion, loose pins, damaged locks, and strained wiring.
- Check the sensor ground and reference connections for stability against the wiring diagram and manufacturer's specification.
- With the vehicle stationary and following safe service procedures, gently move the harness while monitoring the signal for interruptions.
- If wiring and ground remain stable, test the sensor output through its operating range and replace it if the signal is erratic.
Common fixes
- Reseat and secure the sensor connector.
- Clean corroded terminals and repair loose or damaged connector pins.
- Repair an unstable sensor ground or damaged harness section.
- Replace the position sensor if its output remains erratic with sound wiring.
Can I keep driving?
Avoid driving if shifting becomes unpredictable or the transmission enters limited operation; an unexpected gear response can be hazardous. If symptoms are intermittent, drive only as needed to reach a safe place for diagnosis because vibration may bring the fault back.
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.