CageyH

Once back at home, the car refused to start again. As it is two hours away, there is not much Incan do to help my colleague.

Head unit Part number is 3V0035820

Where can I download the MOI3_EU_SKMQB_R23802P file?

Good news - my colleague made the two hour drive home without breaking down. The problem with the over 90km/h fault is that when this happens, there are no fault codes logged. I think it is linked to the loose battery terminal, and the EVU resets itself, due to a dodgy power supply. I have asked my colleague to try the car now that the starting issue is fixed. She is going to try it soon, and let me know.

100% starting record since I tightened the battery terminal. The “coughing” did not happen today either. My colleague is driving home tomorrow, so hopefully she will make it without breaking down on route. She also tells me that if she goes above 90km/h, she gets the dashboard lighting up like a Christmas tree, and a beeping, and is forced to restart the car. I asked her if this started the same time that the garage replaced her battery, but she does not remember. I am starting to think that the car has a few more serious electrical issues, which I am not sure I want to tackle.

The car started again this morning. My colleague did not drive it in, as she said “it coughed” and she did not want to get stranded. Now I need to work out what “it coughed” means.

The car started again this morning. That is a 100% record since tightening up the battery connection. Is it too early to declare it is fixed?

Battery voltage was 12.5V after she started the car, and had turned the engine off. I am not 100% sure it needs a new battery yet. We will see what happens between now and Monday.

My colleague has just let me know that the car started ok, but was a bit lazy to start. Progress… I will keep an eye on it over the next few days.

Thanks. I was Googling after asking the question. You beat me to it. I remember seeing above 200 rpm when I looked yesterday, and there was not a significant difference with the booster fitted. The big difference was that the booster was fitted to the lead, before I tightened up the loose terminal. I am hoping that I get some positive feedback on Monday that the car starts fine, as after tightening the terminal, it started on the button.

Any idea of what the minimum cranking rpm is? It is something I can check with my code reader, using the live data stream.

No start/stop as far as I am aware. I don’t think the battery was coded. I will check. I was going to fit an AGM for the increased CCA capacity. For me, the higher the CCA, the better.

Agreed. This is why I did not want to replace the battery yet. The garage where my colleague had the work done had visited the car recently because it would not start, after they had serviced it. They found no problem with it. The problem is that the garage is about two hours away from where she works. My other thoughts are that one of the relays may be a bit tired, and the extra current available from the booster pack is (more than) enough to operate it. I will see how things progress over the following week, but I am looking at an AGM battery with a higher CCA than what my colleague has fitted. The battery fitted is one typical of a “country” garage here in France. It is a brand I have never heard of, and I have my doubts over it’s capacity. My colleague told me that her problems started when the garage changed the battery. It could be that the terminal has been loose since then. I hope my colleague will keep me informed over the weekend.

I guess a cold cranking test can be done by just measuring the battery voltage across the terminals while starting the engine? What is the target voltage? I would have spent longer troubleshooting, but the weather was not very good.

There was no noticeable difference in cranking speed with the booster pack connected. When I disconnected the booster pack, I did notice that the +ve battery terminal was a little “wobbly”, so I have fixed that minor problem.