To understand the code, you must break it down into two parts: the and the Fault Type (15) .
Even if the lamp is dry, the multi-pin connector at the rear of the lamp assembly is exposed to road spray. Salt and moisture cause green corrosion on pins 2 or 3 (the turn signal feed). This corrosion changes the voltage drop, triggering the B109C-15 logic. land rover b109c-15
: This code frequently appears after swapping standard halogen bulbs for LED units or "logo" puddle lights. Many aftermarket LEDs do not have the correct resistance, causing the Door Module to detect a circuit fault. To understand the code, you must break it
Do not panic. Perform the swap test first. If the fault moves, you simply need a new lamp. If it doesn't, check your battery and your grounds. In the worst case, a dealer software update will silence the gremlin. This corrosion changes the voltage drop, triggering the
With the turn signal activated (hazard lights on), use a multimeter at the connector: