Jump to content
Derrickteo

Auto start stop problem..?

Recommended Posts

Hi everyone. I am new to this forum. I bought a second hand XF 2.2 Diesel about 4 months ago. All is good with it, and I had been enjoying the ride of my life. However, one small nagging issue, sometimes, the auto start stop function is not available.

 

Not that it causes me any inconveniences, I always turn it off anyways. But I am just wondering if there are any problems with the ECU or whatever..?

 

Can any experienced person please advise?

Share this post


Link to post
Share on other sites

A possible reason is that the Battery Management System (BMS) is not charging the Start/Stop battery. It is likely you have auxillary devices installed that is draining too much power AFTER the BMS has learnt the max electrical load. Solution is to get Wearnes to reset your BMS and then turn on all your devices. This includes leaving the start/stop function ON. Once the BMS has learnt the max electrical load of your car (possibly within a month of driving), you can then choose to turn off some of the functions that drains electrical load.

Share this post


Link to post
Share on other sites

I see. That makes sense. I have installed a tire pressure monitoring system and also put a hand phone charger perpetually stucked in the cigarette lighter socket. I will remove these devices and observe.

 

To clarify, if indeed it's the BMS, then there is no lasting impact to the core function of the car, am I right?

Share this post


Link to post
Share on other sites

Removing the devices at this juncture will make no difference. That is because you probably disabled the Start/Stop function (the highest electrical load) at the time when the BMS is learning the electrical load. From my experience, the only way is to reset the BMS and then re-connect all devices, including enabling your Start/Stop function.

Share this post


Link to post
Share on other sites

I face this issue also BUT i can assure u.. it is OK! There is this small little extra batt along ur bigger one.. that the one that is using the start/stop.. unless u want to change that batt,, damage around $500 - $600 thou..

Share this post


Link to post
Share on other sites

The ECO start stop function will only activate if :

  • there are enough battery charge remaining, &
  • the in cabin temperature below a certain threshold

if the above condition is not met, the eco start stop will not activate. 

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

×