Changing battery on Ford S-Max Mk2

[RacingPete]

My wife's S-Max battery isn't holding any charge (around 7 years old and on its original battery by the looks of it), so looks like it needs to be changed. Now in the olden days I would just pop down Halfords, get a battery and replace the thing, but how much do I need to care about coding?

What is the worse that happens if it is coded wrong and I change the battery? Nothing at all, or a few error codes, or something more fundamental?

[Spare tyre]

RacingPete said:

My wife's S-Max battery isn't holding any charge (around 7 years old and on its original battery by the looks of it), so looks like it needs to be changed. Now in the olden days I would just pop down Halfords, get a battery and replace the thing, but how much do I need to care about coding?

What is the worse that happens if it is coded wrong and I change the battery? Nothing at all, or a few error codes, or something more fundamental?

Possibly easier Said than done, but you could run jump leads from a good battery to the terminals whilst you swap the battery, to keep 12v

I’d suspect a Ford will probably be ok with it being disconnected mind. Perhaps search out an owners group

[Cabinet Enforcer]

If it has stop/start then you ought to re-set it so the ecu knows it is a new battery. The only problem I have come across on modernish Fords is that the physical process of swopping the battery is a good deal more difficult, nothing insurmountable but it's no longer a 2 minute job with a 10mm spanner.

[RacingPete]

Thanks, both - so after a lot of Googling tonight I think I can safely replace as long as I use the same battery type and reset the BMS Monitor.

Looks like you can reset it without any diagnostic tools too as follows (which works on S-Max too)



I will also put my jump battery pack attached to the terminals to keep power while swapping.

[shakindog]

As said above not a straight 10 min thing to change as air box out and few other bits to move out the way and access to rear negative 10mm is limited. Usually have to slide battery forward so you can get to it. but is doable diy.
No coding needed
As long as it’s the equivalent as in flooded,efb or agm fit and drive it will sort itself out.
It’ll be a 110 or 115 efb if has stop start or 096 flooded I believe

[RacingPete]

Just wanted to complete this thread for anyone else searching for the same question (or me in 5 years' time).

So picked up a battery from Halfords (same EFB 110 model as currently in the car).

To fit was pretty straightforward, removed the air filter cover using the two clips at the side, unconnected the sensor, and then unscrewed the hose clip on the air intake on the far side and the filter popped off to one side - did have to remove one of the retaining clips for the sensor wire to get the air filter top out the way.

Then undid the two captive screws at the air filter intake on the front of the car - once they were undone, the filter was removed easily.

This enabled access to the battery, one bolt was removed from the retaining plate and then moved some of the wiring loom from in front and the battery out of the way and the battery easily slid out.

Tried to keep the car connected to my external battery jump pack, as I replaced the battery and did reverse of the above.

Car was spot on after, start / stop working as normal and all fixed without doing any resets etc as mentioned above.

Thanks for the advice above

[Peanut Gallery]

Thank you for the update!

(I disconnected my Mk2 battery a while ago - child emptied an entire drink into the passengers seat, around the pre-tensioner etc - seat dried out fine, no codes, all good -and yes, the stop start has not worked for ages, one day I will replace my battery)