It Doesn’t matter what the OBDII device is, my truck just doesn’t like it. When my truck is not connected to anything to monitor temperature, it runs perfectly. Stop and go, highway, it doesn’t matter and regardless of weather conditions and ambient temperature. It just runs great and with no warning lights whatsoever.

Whenever I connect an OBDII device to it, the Bluetooth ones or the scanner kind, the truck will once in while flash the CEL light and the OBDII device can power off automatically. It can even stalled the truck. This happens most often at night with the headlights on and the brakes lights being applied and the full accessories on. It’s almost as if the truck is saying I can’t power all that and keep your stupid OBDII running.

Voltages are fine (13.9 to 14.6V) depending on the temperature. As problems go, this is an easy one to solve, I just don’t connect the OBDII to anything. Just wondering if anyone else has ever encountered anything similar in their Disco II’s.

 

Wonder if it could be a ground issue my speedo would stop working or fluctuate drove me nuts. And OBDII would stop responding to. 1 stupid loose ground in the engine compartment.