P0910: Gate Select Actuator Circuit/Open

What it means

Open circuit detected at the gate select actuator output, used to move the shift mechanism between gates on automated manual transmissions.

At a glance

• Usually lights the check-engine light

How it works

The gate select actuator moves the shift mechanism between gates on an automated manual transmission. The TCM monitors the actuator output circuit, and this code sets when the circuit is open, preventing the actuator from being commanded reliably.

Common causes

Most likely first.

1. Actuator winding open
2. Wiring break
3. Pin pushed back out of connector body

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

1. Save freeze-frame data and check live actuator commands to confirm whether the open is detected when the TCM requests a gate change.
2. Inspect the gate select actuator connector for a backed-out pin, poor seating, corrosion, or damaged wiring.
3. With the circuit isolated according to the manufacturer's procedure, check continuity through the actuator wiring for an open.
4. Test the actuator winding against the manufacturer's specification to see whether it is internally open.
5. If the winding and wiring pass, check the TCM-side connection and output using the manufacturer's procedure.

Common fixes

• Reseat the actuator connector and secure any backed-out pin.
• Repair a broken or open section of gate select actuator wiring.
• Clean or replace damaged connector terminals.
• Replace the actuator if its winding is confirmed open.

Can I keep driving?

Avoid unnecessary driving and do not rely on the transmission to change gates; stop if you cannot select a gear safely. A vehicle may retain some operation, but repeated shift attempts or a missed gate can leave you without drive.