C5 Aircross -Boot issues

[Reedie]

Hey folks,

I am having issues with my boot on my C5 Aircross. I am not sure if it’s a genuine issue or I have changed something.

I have keyless entry and power boot. Previously I could open the boot if my key was in my pocket or swipe my foot under the bottom of the car.

Since coming back from holiday and my car being parked up for two weeks I haven’t been able to open the boot unless I unlock it using the key first. If I try it beeps like I am doing something wrong. Also the boot waving doesn’t work.

Any ideas? I expect I have messed something up as boot works when unlocked. I have been through settings and manual and not been able to sort it.

Thanks!

[PaulC5]

Check the battery voltage, if lower than about 12.5 volts first thing in the morning before starting the engine then it could do with a charge.

[GiveMeABreak]

If the car has been left standing for 2 weeks the battery will be weak and needs topping up. The vehicle has many systems that remain active when the vehicle is unused and these will result in a drain on the battery - especially if you have hands-free.

[Reedie]

Thanks both will give that a try!

[Reedie]

It’s sitting at 12.68v so looks alright from a battery respect.

[Reedie]

Would it be worth disconnecting the battery to reset it?

[GiveMeABreak]

Not really - the energy management is undertaken by the battery charge status unit and the BSI - the BSI will disable certain consumer equipment if it presents a risk to the overall status of the system.

When you get some decent weather, get a smart charger on the battery (you can charge the battery on the vehicle) - consult your car manual on the connection points for this. It's not all about Volts, it's about the health of the battery overall and anything under a certain percentage can mean certain functions are disabled (Stop & Start, certain electrical equipment when the vehicle engine is switched off) etc.

The Battery Charge Status Unit will adjust itself once the vehicle has been charged and the charger disconnected. It may take overnight of non-use to calibrate itself.

[Reedie]

Thanks.

The battery is less than 1 year old. I changed it out as was having problems with stop/start previously.

I will see if I can get a charger and give that a bash.

[GiveMeABreak]

Ok, a smart charger is recommended as it can maintain the battery after it has finished charging and has protection circuits etc.

I know on mine that anything under 80% and "Computer says no". I already had a new battery under warranty, but given my short journeys and occasional use, the same thing happened, so I just leave it as it is now. A few days ago I had to go on a rather longer run all day to the dentist and on the way home at the end of the day Stop Start decided it was going to work again, - so the long run just topped it back up again.

[Reedie]

I am doing a long motorway trip this weekend so will give it a try after that.

I know what you mean though since Covid I am the same lots of small journeys and no regular longer drives

[GiveMeABreak]

No worries, let us know if this sorts it out.

[Rp0thejester]

I think it's important for people to remember that there are capacitors fitted to electronic circuit boards, they hold power like a mini battery so if the car isn't used for awhile the capacitor will keep the system running. If not used in along time the capacitor will deplete it's energy as it's not being renewed from the car battery. So additional extras like foot to open boot first would stop rather than car alarm or any other security device.

[GiveMeABreak]

It's all dependent on main battery charge. Energy management on modern vehicles is micro-managed to a high degree, and some systems require a minimum amount of power before they will work. With 30+ ECUs on this vehicle, each requiring specific conditions and voltage levels to operate it's just going to be a main battery issue.

Electronic systems are on different CAN networks depending on prioritisation / categorisation, such as safety critical systems / Powertrain Systems and comfort systems etc. These are all prioritised accordingly but the BSI will do what it has to, to ensure the vehicle will start as far as it is able, like disabling Stop Start / tailgate opening and use of accessories while engine is off.

[Reedie]

I did a long motorway journey 3+ hours and didn’t make a difference.

It looks like the aerial for the key at the back has gone.

I gave in and put it into my local garage. They are saying it needs a new tailgate motor which seems bizarre to me. They have said it is logging the key isn’t present.

I may have to get a 2nd opinion

[GiveMeABreak]

I'm not sure I believe that. Does the motor operate to shut and open using the button (try with the engine running) if it does, I can't see it being that.

Best to pop your VIN up so I can see what you have. Please post your VIN in full without spaces - it will be automatically masked from public view after submitting your post & will only be visible to staff.