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Diagnostics required

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My Insignia B failed to start last week. it had started in the morning but the dash lit up like a christmas tree (low battery, faults on BCM etc) but running for 20 mins just made it worse. Now it doesnt turn over and have lots of faults ( theft deterrent being one of them). 

Changing the battery has not helped, and jump starting from another car/battery may have damaged/disabled various BCMs?


A local garage has managed to revive some of the control units but say that the remainder and the ECU are not communicating. They also said that the (new) battery had completely discharged and that charging it overnight may have assisted in recovering communications with several of the BCMs.

I have it booked into a specialist in 2 weeks time that has high level diagnostics, but my questions are:

1) Is it likely that I can fully charge the battery and progress beyond where i am by “resetting” BCMs that have been disabled rather  than damaged?

2) Is it worthwhile in any way investing in a high quality diagnostic scanner (AUTEL MX808 or similar) or will this still leave me unable to communicate at a high enough level with the car or determine that specific components definitely need replacing?

thank you. 


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I would definitely start with the battery from the terminals (clean and tight) to the leads, especially all earth leads are intact and clean as these are often overlooked.
After that, with the battery on trickle charge I would let the control units relearn their parameters and then try it after that.


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Thanks. The battery is new (Bosch S5 AGM) and the terminals look good but i’ll clean them and the earth points too. 

Can you elaborate on what “relearn” means? should i leave the battery connected when trickle charging, or remove, trickle charge completely then re - attach? How do the control units relearn their parameters?

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If you are trickle charging then leave the leads connected if it is a smart-charger / battery conditioner. If it is an old trickle charger then I would be tempted to leave the terminals off if leaving the car for a long length of time.

ECU's relearn running conditions by running certain checks on start up and adjusting the electronic parameters accordingly, something that is done in the background on every start up and you wouldn't know its going on unless it flags up an error.
Sometimes, the systems 'fall over themselves' with bad (historic) information being stored and this is when you need to hard-reset the system so it can relearn the correct settings.

However, most systems should relearn but sometimes you would need specialist kit to force the system to relearn some information to run from and in which case a local garage should have kit to resolve these issues

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