C1223 Fault Code

Long Description

Fault code C1223 is a manufacturer-specified code used by many carmakers to indicate a Lamp Brake Warning Output Circuit Failure. It is logged when the engine control unit (ECU) has detected an issue with the brake lamp circuit.

This can occur when one of the brake lights does not remain illuminated while the brake pedal is depressed or the brake lights do not illuminate at all even if the pedal is pressed.

This circuit falls under the anti-lock braking system (ABS).

Not all vehicles will have C1223 as a fault code relating to a brake lamp malfunction. However, Lexus and its parent company Toyota are two of the most common manufacturers to report this type of issue. Lincoln is another such manufacturer.

Other Signs of This Problem

There are no driveability issues that this code can cause as it only represents an issue with the brake lamp circuit. This can mean that fault codes and warning lights are the only way to detect the issue.

The most noticeable sign of this issue is the presence of the Check Engine light or Malfunction Indicator Lamp (MIL). The ABS light will also be illuminated on the dashboard.

It is also possible that the rear brake light will not respond correctly. As mentioned, it may go off even while the brake pedal is depressed. It may also not illuminate at all.

Other brake lamp fault codes include C1224, C1225, and C1226. These can be helpful in pinpointing the true issue causing the circuit malfunction.

It is also possible for a damaged or corroded battery to be the cause.

What Could Be The Problem?

Most of the possible causes for this type of issue are related to some issue within the brake lamp circuit. All of these fixes are electrical in nature.

A damaged or faulty brake lamp will not be able to illuminate. This can trigger the C1223 code to be logged.

Damaged or contaminated connections in the wiring harness can also cause this issue. This is also true of damaged or corroded battery terminals.

If there are other fault codes present, these can help determine where the cause of the issue is coming from.

Fixes

Because all of the possible causes are electrical in nature, the fixes for these issues will also focus on fixing electrical issues.

The brake lamps should be checked for proper function. If these lights are damaged or faulty, they must be replaced.

If the lamps are not faulty, it is a good idea to check for any damaged wiring or connections in the wiring harness for the brake lights.

In some instances, the battery terminals should be checked. If they are corroded or damaged, the battery should be replaced. However, this will likely come with other codes that point to this type of issue.

Seriousness

Fault code C1223 can be considered a low code in terms of seriousness. There are no driveability issues present while this code is logged.

However, it is not safe to drive with a malfunctioning brake lamp. It is also illegal in many places, meaning the driver will be liable for a fine if stopped.

It is recommended to have this problem solved as soon as possible.