After retrofitting European taillights on a 2017 Volkswagen Jetta GLI SE (Mk6.5), several error codes appeared, disabling the front LED DRLs and parking lights. This article explores the VCDS codes encountered and potential solutions for resolving the issue.
Understanding the Problem
The original vehicle configuration included North American (NAR) spec full LED taillights, license plate lights, and halogen headlights with integrated LED DRLs and parking lights. The retrofit aimed to equip the vehicle with European-spec taillights with amber turn signals and a rear fog light. All wiring was completed successfully, and initial testing of the rear lights showed no issues.
The VCDS Code: 09 – Central Electronics (Byte 18)
The problem arose after changing Byte 18 in the Central Electronics module (address 09) to “8C – Jetta ROW” using VCDS diagnostic software. While this enabled the desired rear taillight functions, it resulted in the following fault codes within the same module (09 – Cent. Elect.):
- 01502: Bulb for Rear Fog; Left (L46) – Open or Short to Plus
- 02394: Parking Light Left Front (M1) – Open or Short to Plus
- 02395: Parking Light Front Right (M3) – Open or Short to Plus
- 02745: Bulb for Daytime Running Light; Left – Open or Short to Plus
- 02746: Bulb for Daytime Running Light; Right – Open or Short to Plus
These Volkswagen Gli Vcds Codes indicate an open circuit or short to positive voltage in the respective lighting circuits. The front DRLs and parking lights ceased to function, and the parking light position only activated the side marker lights, conforming to US regulations.
Analyzing Byte 18 Options and Potential Solutions
Research suggests that Byte 18 option “8C” applies to Rest of World (ROW) Jettas with separate incandescent bulbs for parking lights and DRLs. This differs from the GLI’s integrated LED setup. The BCM (Body Control Module) needs to be correctly configured for the LED DRL and parking light combination.
Another Byte 18 option, “Hex 90”, is potentially compatible with the GLI’s lighting configuration. The key difference lies in the “TFL_1_LED” designation within Hex 90, suggesting proper recognition of LED DRLs. This contrasts with the “TFL_1” designation in Hex 8C, indicating incandescent bulbs. Switching to Hex 90 may resolve the issue. However, careful consideration is needed before modifying Byte 18 again.
Conclusion
Retrofitting European taillights on a North American Volkswagen GLI can lead to unexpected complications with the front lighting system. Understanding the volkswagen gli vcds codes related to these issues is crucial for diagnosis. While Byte 18 coding offers potential solutions, further investigation is recommended to ensure the chosen coding accurately reflects the vehicle’s specific lighting configuration and avoids further issues. Consulting with experienced VCDS users or Ross-Tech support may be beneficial.
