P0907: Gate Select Position Circuit High

What it means

The gate select position circuit A reports a circuit a high fault. Selector gate position cannot be reliably measured.

At a glance

• Usually lights the check-engine light
• The engine or gearbox may go into limp mode

How it works

The gate select position sensor reports which shift gate the transmission selector has reached. The TCM monitors circuit A's signal, and this code sets when it reads higher than the expected range, so the selected gate cannot be confirmed reliably.

Common causes

Most likely first.

1. Signal wire shorted to B+
2. Open sensor

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. Record freeze-frame data and check live gate-position data to see when circuit A first reads high and whether the reported gate changes.
2. Inspect the gate-position sensor connector and circuit A wiring for damage, water, corrosion, or a signal wire contacting a power feed.
3. Check whether the sensor has its required supply and ground, then compare its signal with the manufacturer's specification.
4. With the circuit isolated as specified by the manufacturer, check whether circuit A is shorted to B+.
5. If wiring and connections are sound, test the gate-position sensor for an internal open or a signal that remains high, and replace it if confirmed.

Common fixes

• Repair a signal wire shorted to B+.
• Clean and secure the gate-position sensor connector and restore damaged terminals.
• Repair an open or damaged section of circuit A wiring.
• Replace the gate-position sensor if testing confirms it is open or its signal stays high.

Can I keep driving?

Avoid driving if shifts are missing, the transmission slips, or the vehicle is stuck in one gear; arrange recovery if control is unpredictable. Continued driving can worsen transmission damage or leave you without the gear needed for safe traffic.