[TG] [DG11] ACU-400 not detected ('No Pilot' error)

[Tom - Raymarine - Moderator]

Hello SaltySeaPup,

The message you're seeing is definitely 'No Pilot'? That message means no communication with the EV1: a comms problem with the ACU should give you 'No Drive Detected' instead. I would like to make sure we chasing the right fault.

If you are sure that the ACU's STNG cable and power supply are good, and that there's no problem with its connection point into the network, and that everything else on the network talks together, then that sounds like the ACU's STNG CANbus communications chip has been damaged I'm sorry to say. In my experience that usually happens from one of the following things:

• nearby (not direct) lightning strike or other ESD inducing a high voltage transient onto cabling
• multiple power-supplies in the NMEA2000/STNG network
  

There's no rock-solid way of making sure whether this has happened: measuring the resistance between the blue and white terminals of the STNG connector of the ACU when power is not connected can sometimes show an outright failure, but the real diagnostic tools for this sort of thing are an oscilloscope and a CAN analyser which a good technical Service dealer should have, but few others I'm sorry to say.

If the CAN chip has been damaged then the ACU would need replacement: component-level repairs of conformally-coated, multi-layer, surface-mount PCBs like this aren't really practical any longer.

Regards,
Tom