Thread: Strange goings on with auto

The M&S lights and the XYZ switch , or low battery will generaly not cause a shutdown. A totally collapsed battery would ,but you would know about that! The inertia is a good place to start I think. A overheat will cause the ECU to shutdown but again something you would notice! unless there is a faulty sensor related to it
Good luck!
Cheers Scott

Thanks. Unfortunately it's the sort of problem I only will know is fixed by the lack of faults, so will be on tenterhooks for the next few weeks. Not going too far from home, anyway.

My D2 had the same problem when towing van. New clutch packs fitted in Albany at 110K ks never solved problem. Sold D2 @ 320K ks now have D3 with auto gearbox problems.

I'm reasonably convinced that it's electrical. The only fault that logs is one from the auto box and refers to the CAN bus timeout, so the Auto ECU and engine ECU aren't talking. Other options are a poor earth, frayed cable or loom, or XYZ switch (got one off eBay on its way). The other thing that can cause the logged fault is low volts, and I replaced the battery as it was on its way out anyway.
Current thinking is that the inertia switch going dropped power to the BCU (which it's designed to do). The CAN timing fault either happened because of that, or it had happened before the other fault and I hadn't noticed. Will be interesting to see. The Inertia Switch certainly feels dodgy, as if its been overcooked at some stage, and the plug is brittle and cracked when I unhooked it from the switch. They'll both need to be replaced (or not).

If I'm right, it's frustrating that the Inertia switch doesn't log a fault, as I've been off chasing a fault that wasn't the real problem.

Yep, more than a week later and no further faults. It was a dodgy inertia switch. All I've done is bypassed the switch by disconnecting the plug and dropping half a paperclip in between pins 1 & 3 and taping it up with electrical tape. WIll have to replace the switch at some stage.

Lesson learnt: While the Nanocom is great for throwing up faults, you need to actually do a bit of intelligent thinking with diagnosing faults, and not just assume that because a code is thrown, then that is the fault itself.