P0912 Gate Select Actuator Circuit Low

P0912 indicates the gate select actuator circuit is low. The actuator control path is grounded, missing voltage, or drawing less current than expected.

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 replace the gear mechanism until the low actuator circuit is tested under load.

Symptoms of P0912

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 P0912

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 actuator command voltage, feed, ground, resistance, and current while checking for short-to-ground and voltage-drop faults.
Inspect connector pins, relay or fuse supply, module driver output, harness routing, and actuator winding condition.
Compare the low circuit event with gate position feedback, failed shift attempts, and freeze-frame temperature or voltage data.

Related OBD-II codes

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