John Deere D1a Code !!better!! Full Site
If you have replaced the faulty light and inspected all the visible wiring but the still returns, you may have a damaged Lighting Control Module or a short inside the main harness. At this point, a dealer technician with a Service Advisor laptop is your best bet.
The fix for the D1A code may involve:
There are several possible causes of the D1A code, including: john deere d1a code full
Let us be clear: that is legal under EPA/CARB regulations. Attempting to install an "emissions delete" on a John Deere FT4 engine is a federal offense in the US and carries fines up to $37,500 per day. If you have replaced the faulty light and