C0023: Stop Lamp Control

What it means

The code identifies a fault in the stop lamp control function monitored by the brake control module. It sets when the module detects that stop lamp operation or its control signal does not match expected conditions.

How it works

The stop lamp control function operates or monitors the brake lights and their control signal. The brake control module stores C0023 when the stop lamps or the signal indicating brake-pedal application do not match expected conditions.

Common causes

Most likely first.

1. Failed brake light bulb
2. Faulty stop lamp switch
3. Damaged wiring or connector
4. Blown fuse
5. Brake control module fault

Symptoms

• Brake lights stay off
• Brake lights stay on
• ABS or brake warning light

How to diagnose it

1. Check whether all brake lights illuminate when the pedal is pressed and go out when it is released.
2. Inspect the brake-light bulbs, sockets, and visible wiring for failed lamps, corrosion, or damage.
3. Check the stop-lamp fuse and its connections using the vehicle’s fuse information.
4. Compare the brake-pedal switch status on a scan tool with actual pedal operation to identify a switch or adjustment fault.
5. Inspect the stop-lamp switch connector and wiring, then test the circuit using the manufacturer’s procedure.
6. Check the brake control module only if the lamps, switch, fuse, and wiring test correctly.

Common fixes

• Replace a failed brake-light bulb or repair a corroded lamp socket.
• Replace a blown fuse after checking for a short or overload.
• Adjust or replace the faulty stop-lamp switch.
• Repair damaged stop-lamp wiring or connector terminals.
• Repair the brake control module if it fails testing after circuit checks.

Can I keep driving?

If the brake lights do not work or stay on, other drivers may not know when you are stopping, and the fault may also affect brake-related controls. Avoid driving in traffic until the lamps operate correctly.