P0922: Gear Shift Forward Actuator Circuit Low

Set when the drive circuit of the forward shift actuator of an automated manual gearbox shows a voltage that is too low for the current switching state. This usually points to a short to ground on a valve or motor line, or to an internal short in the actuator. Many controllers then switch the output off to protect the driver stage. No manufacturer documents this code publicly. A ZF patent drives each chamber of a double-acting shift cylinder through its own solenoid valve, and an Isuzu patent runs an electric shift motor in both directions, so a fault can affect one shift direction only. CARB requires circuit checks on outputs. P0923 is the opposite high fault, P0920 the open circuit, P0926 the reverse direction. Gears in this direction are blocked.

Medium severity. Can I keep driving?Drive as little as possible and gently. If the transmission slips or stays in one gear, go slowly to a repair shop or call for a tow truck.

Symptoms

Transmission warning light on
Certain gears can no longer be engaged
Gearbox may stay in neutral or hold one gear

Most likely causes

Drive wire chafed through and shorted to ground
Internal short in solenoid coil or shift motor
Water or corrosion bridging pins in the connector

What to check, in order

Start with the simplest. You can tick off each step.

Check the fluid level and condition according to the manufacturer
With the connector unplugged, check whether the signal wire is making contact with ground.
Check the transmission connector
Read the data with a transmission-compatible scanner
Measure the solenoid valve circuit
Leave opening the transmission to a specialized repair shop

Good to know

Repair difficulty: hard
It can trigger limp mode.
It affects emissions.

What each character of P0922 means

P: Powertrain: engine and transmission
0: Generic code: same on every make
9: Transmission
22: Specific fault in that system

Frequently asked questions

Can I keep driving with code P0922?

Drive as little as possible and gently. If the transmission slips or stays in one gear, go slowly to a repair shop or call for a tow truck.

What causes code P0922?

The most common causes are: drive wire chafed through and shorted to ground; internal short in solenoid coil or shift motor; water or corrosion bridging pins in the connector.

Related codes

Sources

Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.