Good morning

My cmax has developed an intermittent fault that is a right pain in the bottom. The fault occurs when trying to start the car it with either start first time and work perfectly or will refuse to start and then deliver multiple warning messages on the instrument cluster including: immobiliser fault service now, engine service now, faults with parking aid and faults with citystop. When I've plugged in forscan to the car I get multiple errors mainly along the lines of lost communication between modules and the bcm spits out multiple error codes relating to signal loss from sensors but only when the car doesn't start. It will be running happily and if you switch it off and try to restart it will then give you all the faults again so I can't trust it at all my plan is to take it to a local auto electrician but I thought it might be worth asking if any of you lovely people might have any idea's.

Things I've tried so far: booster pack (battery in good health), remove battery for 30 mins to reset modules, reset modules via forscan, looked at start inhibit in pcm when car won't start to see if they are active they weren't. Checked all plugs into bcm and removed and refitted all to no avail so any help you might have would be appreciated.

It doesn't sound like the battery is in good health to me.

Why are you using a booster pack if the battery is in good health?

When it first did it I tried a booster pack to see if it was a battery issue. I was stranded by the roadside in the middle of nowhere so I had to try something I had no tools with me other than a booster pack which is always kept in the boot.