P0906 Gate Select Position Circuit Low

P0906 indicates the gate select position circuit is low. The position signal is below expected range or pulled toward ground.

Code details

Generic OBD-II · P0

System: Transmission
Code type: Generic (SAE / ISO controlled)
Standard: SAE J2012 / ISO 15031-6

Diagnostic boundary

A diagnostic trouble code reports that a monitored test failed. It does not prove one specific part is bad, and manufacturer logic can add vehicle-specific conditions.

Do not perform adaptation relearns until the low position circuit is electrically stable.

Symptoms of P0906

Harsh, delayed, or slipping shifts, or being stuck in one gear.
Check-engine light, sometimes with limp-home mode.
Flaring RPM or a shudder under load.

Common causes of P0906

Low or degraded transmission fluid.
A failing speed sensor, shift solenoid, or pressure-control circuit.
Wiring, connector, or internal hydraulic/mechanical faults.

Useful checks before replacing parts

Measure gate position signal voltage, reference voltage, ground, and continuity while moving the selector or actuator through travel.
Inspect connector terminal tension, short-to-ground faults, sensor mounting, harness rub points, and shared reference circuit issues.
Compare gate position data with actuator command and gear selection state to confirm when the low signal appears.

Related OBD-II codes

These nearby transmission entries can help compare wording and pin down the fault area.