I have antara 2.2 diesel stop / start 2012yr. I recent suddenly had occasions when starting engine when warm after driving and resting / engine stopped on key, To restart engine seemed rattle noises,
This worried me (no dash warninglights seen at anytime whilst driving)
Then yesterday, I come out of home having already been on a 50miles round trip without stop / start system active and without stopping engine manually.
As soon as I turn the ignition key, all dash lights went out and car appeared to have died, NO interior lights, horn. hazard flashes etc.
I rang AA (warranty assist),
The guy came and did full diagnostic from port connector below dash. NO Fault codes!
Battery power12.4volts. Then did across main battery check with inspection lame loading across battery, Still 12.4v and light lit. He decided to slave start it with booster box from the rear of theAA van. The engine sprung into life and he was able to check charge from alternator, 13.8 / 14.0 volts fluctuating slightly between both readings.
It was concluded the battery had been failing for a while and suddenly died totally without warning by slow starter motor or dash lights etc.
We tried to locate somewhere which could supply AMG battery (Local Vauxhall dealership said 3 days ordering one specially). several other reputable outlets were tried.
The AA man said they had their own suppliers scattered across uk. He went away from about and hour leaving his power box retaining my security codes. On his return the main battery was replaced and without any issues the engine started. It's vital that if your vehicles is a stop/ start model you have a AGM battery 95 Amp/Hr rating battery installed. My fault / failed battery was manufacturer original and around 4 and 1/2 yrs old. These batteries cost anywhere between £250 and £380. Costly but warrantied for another 4yrs. I was pleased it was only battery, not something else,