Urgent help needed please

[OldEngineer]

I can see on your attachment many fault codes for a trailer 'short' of some circuits. All the rest are codes related to the 'Start Up' voltage checks (which will fail for insufficient battery or earth)

So, the Trailer Electrics are poor and you travelled for several miles until the steering demanded extra current and that exposed the poor electrics.

PS. The Battery Monitoring System (BMS) needs to unscramble the effects of separating the two batteries while you charged them. The BMS has no information on the relative battery states.

[wynnj]

Originally Posted by OldEngineer

I can see on your attachment many fault codes for a trailer 'short' of some circuits. All the rest are codes related to the 'Start Up' voltage checks (which will fail for insufficient battery or earth)

So, the Trailer Electrics are poor and you travelled for several miles until the steering demanded extra current and that exposed the poor electrics.

PS. The Battery Monitoring System (BMS) needs to unscramble the effects of separating the two batteries while you charged them. The BMS has no information on the relative battery states.

Thanks again for replying. This was just one page of many relating to failures on most of the car's modules which I understand if there's one major issue with something pulling canbus signals down, but I don't understand why it was OK for nearly 50 miles after the SW installation before failing, and whilst I understand that the steering takes a high current I'd have used full lock getting in and out of my driveway before this happened.

I am very disappointed that a fault on a secondary system should result in such catastrophic failure, including the hazard lights, especially the latter when you need them the most.

Will the BMS sort itself out over time? I don't really understand what it does. Having reconnected both batteries I left it all on charge via the underbonnet charging posts last night and my CTEC charger had lamp 7 illuminted this morning so hopefully all is fully charged now.

It's good to know there's some good technical knowledge available for these SPA cars as I've found on this forum for years for the P2 cars. I was very pleased to have still got my 17yr old S60!

[GMcL]

I think the others have helped you find your source, what is the mA drain on the car after it has been switched off for a couple of hours ?

I had an issue with our EV where the 12v battery was dead usually after an OTA update. The issue was a dashcam and phone charging cable being left plugged in - not suggesting this is your issue, the dash feed was not shutting down when anything was plugged in. Once resolved the car now pulls between .22 and .25mA at rest.

[wynnj]

Originally Posted by GMcL

I think the others have helped you find your source, what is the mA drain on the car after it has been switched off for a couple of hours ?

I had an issue with our EV where the 12v battery was dead usually after an OTA update. The issue was a dashcam and phone charging cable being left plugged in - not suggesting this is your issue, the dash feed was not shutting down when anything was plugged in. Once resolved the car now pulls between .22 and .25mA at rest.

Thanks GMcL. I was talking in general terms when talking about sharing expertise, and appreciate all the replies people have taken the trouble to give. There's a lot less available for SPA cars which is one reason I've tried to explain all I've found in some detail in case it helps others in the future.

I haven't done a residual current drain test yet, partly because having got back to a stable situation (so far at least) I don't want to disturb anything until I know it is fixed for certain, also I didn't know what would have been normal, so thanks for specifying what yours reads.

One other thing I should add as a reminder (or info if not already known) is that when the car is completely locked up in Park and you can't select Neutral to move it there's a release mechanism in the frontmost cubby tray. You pull up the rubber liner and there's a hole into which you can press down on a release catch and you can then move the gear selector. Fortunately I remembered before the recovery truck arrived; if I hadn't I dread to think what he'd have done as he didn't know it existed. I had a 10cm touch screen stylus pen in the tray which fitted into the hole perfectly. I was also able to release the handbrake. Again I don't know what they'd do if power to that is lost.

Oh for my old moggy minor. It leaked round the windscreens, had very little heating, misted up, didn't go very fast but was relatively easy to fix when it went wrong!!!

[OldEngineer]

Originally Posted by wynnj

Thanks again for replying. This was just one page of many relating to failures on most of the car's modules which I understand if there's one major issue with something pulling canbus signals down, but I don't understand why it was OK for nearly 50 miles after the SW installation before failing, and whilst I understand that the steering takes a high current I'd have used full lock getting in and out of my driveway before this happened.

I am very disappointed that a fault on a secondary system should result in such catastrophic failure, including the hazard lights, especially the latter when you need them the most.

Will the BMS sort itself out over time? I don't really understand what it does. Having reconnected both batteries I left it all on charge via the underbonnet charging posts last night and my CTEC charger had lamp 7 illuminted this morning so hopefully all is fully charged now.

It's good to know there's some good technical knowledge available for these SPA cars as I've found on this forum for years for the P2 cars. I was very pleased to have still got my 17yr old S60!

My assessment is still a loose Earth. The circuit would be enough for a few miles and maybe a few full locks. But at some point the steering needed a lot of assistance. Maybe the it was the first time you were stationary and pulling with more effort on the wheel. At this point the Earth gives up. Now all the circuits are deciding there is less than the required 12.7 volts so they all give fail messages. They haven't failed but just recorded a low voltage. Then all the serious stuff stops working because there really is a lack of volts.

The BMS will sort itself out and probably helped with the C Tec session. My Support Battery reported that it needed a service but it was just the BMS getting confused. A session on a charge at the front posts sorted it.