A flashing glow plug warning light and a Vcds 16955 error code often point to a faulty brake light switch. This article explores a troubleshooting process for this common issue in Volkswagen and Audi vehicles. Initially, the problem appeared intermittently, with the glow plug light flashing while driving. Stopping the car often reset the light, but it would reappear. Brake light functionality was also affected, operating intermittently.
A VCDS scan revealed the 16955 error code. Research indicated that faulty brake light switches are a common cause of this code. Two replacement switches were obtained: a purple and a green one. The original switch was black and a different shape.
Installing the purple switch resulted in permanently illuminated brake lights. The green switch, as well as the cleaned original switch and a switch from a T4, allowed the brake lights to function correctly. However, the fault light reappeared within minutes, even without the switch being mounted. Attempts to clear the fault using VCDS were unsuccessful, with the error immediately recurring.
Although the warning light has temporarily extinguished itself, understanding the root cause is crucial to prevent recurrence. While replacing the brake light switch is a common solution for the 16955 error, the continued issue suggests other potential problems. This could include wiring issues in the brake light circuit, a faulty brake light bulb, or even a problem with the vehicle’s control module.
Further diagnostics are recommended to pinpoint the exact cause. This may involve inspecting the wiring harness for damage or shorts, testing the brake light bulbs for proper function, and potentially checking the control module for any related faults. If the problem persists, consulting with a qualified automotive technician experienced with VCDS diagnostics is advisable. They can perform more in-depth testing and analysis to accurately diagnose and resolve the issue.
