Byte 18 in the Central Electronics long coding helper for MK6 GTI fog delete modifications is often a source of confusion. Unlike older models with “Cold Bulb Diagnosis” options, newer GTIs mask this byte with “00,” making it difficult to determine its true value. This poses a challenge for those attempting fog light deletion using VCDS, as experimenting with different byte 18 values without knowing the original setting can lead to complications.
If modifications to byte 18 are unsuccessful, reverting to the original value becomes impossible. This often leads GTI owners to consider alternative solutions, such as using error-free CAN-BUS LEDs. However, even these LEDs aren’t always guaranteed to be error-free on newer VAG cars with more sensitive bulb error detection systems. What might work flawlessly on an older model might trigger errors on a newer GTI. Finding compatible LEDs often involves trial and error.
Another approach involves using high-wattage (around 50w) load resistors connected in parallel with the LED. These resistors increase current draw, tricking the Body Control Module (BCM) into believing a standard bulb is present. However, these resistors generate significant heat. Careful consideration must be given to their mounting location to ensure proper heat dissipation and prevent potential damage to surrounding components. Improper installation can create a fire hazard.
