P0906
Gate Select Position Circuit A Low
Transmission
Generic OBD-II
Medium
What it means
P0906 means the gate select position sensor 'A' — which reports where the shift mechanism is in its gear gate — is reading an abnormally low voltage. The engine still starts, but the module can't confirm gear selection, so the transmission may miss gears or show the wrong one. It usually points to a faulty position sensor, wiring, or a poor ground.
Medium
Can I keep driving? The engine starts, but the transmission may miss gears or refuse to select some; drive cautiously and have it checked soon.
Common symptoms
What you'll notice
- Check-engine light on
- Difficulty selecting or missing gears
- Wrong gear shown on the instrument display
- Erratic or inconsistent shift behaviour
Common causes
Most likely first
- Faulty gate select position sensorLikely
- Wiring or connector fault (short-to-ground or open) in the circuitCommon
- Poor electrical connection or groundCommon
- Corroded or damaged sensor terminalsLess often
- Faulty control module (TCM/ECM)Less often
How to diagnose & fix
Work through it in order
- Inspect the gate select position sensor connector and terminals for corrosion or damage.
- Check the signal wiring for a short-to-ground or open causing the low reading.
- Confirm the sensor has a clean ground and proper reference voltage.
- Compare the sensor's live signal to spec across gate positions; replace the sensor if out of range.
- Consider the control module only after wiring and sensor causes are ruled out. Clear and re-test.
FAQ
Quick answers
Is it safe to drive with P0906?+
If the transmission still selects gears, drive gently, but missed or wrong gears can be unsafe, so get it diagnosed soon.
Can I just clear P0906?+
It returns until the sensor, wiring, or connector fault is repaired.
Related codes
Often seen with P0906
Read & clear P0906 yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.
✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX