C0023 — Stop Lamp Control (Subfault) #

Note: The code description for C0023 may vary depending on the vehicle manufacturer. Always refer to your OEM (Original Equipment Manufacturer) documentation for the precise definition applicable to your model.

Common description variations by OEM:

• Stop Lamp Control Circuit (Ford, GM, Nissan)
• Brake Light Control Signal (Toyota, Honda)
• Stop Lamp Relay Control (Hyundai, Kia)
• Brake Lamp Control Error (Volkswagen, Audi)

Summary of DTC C0023 #

DTC C0023 indicates an issue with the stop lamp control circuit, which manages the brake lights at the rear of your vehicle. This trouble code is typically triggered when the electronic control unit (ECU) detects a fault in the circuit responsible for activating the stop lamps when the brake pedal is pressed. The problem can arise from electrical interruptions, component failures, or communication errors within the system. While the code itself is linked to the brake light function, it can also impact related safety features such as ABS (Anti-lock Braking System) or ESC (Electronic Stability Control) in some vehicles. Prompt diagnosis and repair are essential for maintaining both your vehicle’s road safety and compliance with legal requirements.

Common Symptoms for DTC C0023 #

Experiencing a C0023 code often comes with noticeable symptoms, most of which revolve around your brake light operation. Ignoring these signs can compromise both your visibility to other drivers and your vehicle’s safety systems. Watch for these indicators:

• Brake lights not illuminating when pressing the brake pedal
• Brake warning light or check engine light illuminated on the dashboard
• ABS or ESC warning indicators may also appear
• “Stop Lamp Circuit Error” or similar message on the vehicle display
• Cruise control may be disabled or malfunctioning

Most Probable Causes for DTC C0023 #

The underlying causes behind a C0023 code can vary, but some issues are more common than others. The problem can stem from simple wiring faults to failed electronic modules. Here’s a ranked list based on frequency:

1. Faulty or burned-out stop lamp bulbs
2. Damaged, corroded, or disconnected stop lamp wiring/connectors
3. Faulty stop lamp switch (the sensor at the brake pedal)
4. Malfunctioning stop lamp relay (if equipped)
5. Failed Body Control Module (BCM) or related electronic control unit
6. Blown fuse associated with the stop lamp circuit

Step-by-Step Diagnostic for C0023 #

Accurately diagnosing a C0023 code requires a systematic approach to avoid replacing unnecessary parts. Here’s a proven step-by-step process:

• Verify the code with a compatible scan tool; note any related codes.
• Check the operation of all brake lights (including high-mounted center brake lamp).
• Inspect the stop lamp bulbs for continuity and proper wattage; replace if necessary.
• Examine all wiring and connectors between the brake pedal, stop lamp switch, and rear lamps for signs of damage, corrosion, or disconnection.
• Test the stop lamp switch at the brake pedal for correct operation and continuity.
• If equipped, check the stop lamp relay for function and power supply.
• Inspect the relevant fuses and replace any that are blown.
• If no faults are found, consider advanced diagnostics on the BCM or relevant control module, following OEM procedures.

Possible Repairs for C0023 #

Once the root cause is determined, repairs can be straightforward or require specialized attention. Always address the underlying issue to prevent recurrence:

• Replace faulty stop lamp bulbs with OEM-specified types.
• Repair or replace damaged wiring/connectors in the stop lamp circuit.
• Replace a defective stop lamp switch at the brake pedal.
• Replace a malfunctioning stop lamp relay if applicable.
• Replace blown fuses related to the brake light circuit.
• Reprogram or replace the Body Control Module (BCM) if it has failed (rare, but possible).

Is It Safe to Drive with DTC C0023? #

Driving with a C0023 code is not recommended. This fault often means your brake lights aren’t working, making you nearly invisible when braking—especially dangerous at night or in traffic. In many regions, operating a vehicle without functional brake lights is illegal and could lead to accidents or fines. If the ABS or stability control systems are also affected, your safety risk increases. Repair this issue before resuming normal driving.

Vehicles Most Commonly Affected by C0023 #

While C0023 is a generic OBD-II/ EOBD code, it’s more frequently reported on some makes and models due to design specifics or wiring layout. If you drive one of these vehicles, be extra attentive:

• Ford F-Series, Focus, and Escape
• Chevrolet Silverado and Equinox
• Nissan Altima and Rogue
• Honda Accord and CR-V
• Hyundai Sonata and Elantra
• Volkswagen Passat and Jetta

Common Mistakes & Best Practices for C0023 #

Misdiagnosis can lead to wasted time and unnecessary expenses. Here are the pitfalls to avoid and best practices to adopt:

• Replacing bulbs without checking fuses, wiring, or switch function
• Overlooking corroded or loose connectors behind the brake lights
• Ignoring related codes (such as ABS or BCM faults) that may point to a larger electrical issue
• Failing to use OEM-quality parts, which can lead to quick recurrence
• Not documenting repairs and test results for future reference

Quick FAQ for C0023 #

Got more questions? Here are fast answers to what drivers and technicians ask most often:

• Q: Can a single burned-out brake light trigger C0023?
  A: Yes. Many modern vehicles monitor each brake light circuit individually, and a single failed bulb can set this code.
• Q: Does clearing the code with a scan tool fix the problem?
  A: No. The code will return if the underlying electrical fault isn’t resolved. Fix the root cause first, then clear the code and verify proper operation.