Lamborghini Talk banner

Aventador wouldn’t start!!

3379 Views 19 Replies 8 Participants Last post by  GallardoM5
Happy new year all.
I am having a nightmare of a problem with my 2014 Aventador Roadster with start stop for over a year now.
It all started with the car not starting when I press on the start button. AlI I heard was a
‘Click’ and dash had ‘start stop fault. System not ready’.
Installed new battery, new super capacitor and new trickle charger and every time we thought the problem was cured, it comes back again.
I tried giving the car a start up yesterday and the problem came back. I’m at my wits end as to what the root cause of the problem is.
if I remove the positive (red) cable on the supercapacitor that goes to the starter motor and connect it directly to the positive terminal of the battery, the car fires up. (By doing this, it is the car battery that starts the starter motor rather than the capacitor). This surely proves my starter motor is ok?
We have checked all the wiring, clean all electrical contacts etc….and the problem still persists.
Any help or advise us greatly appreciated. Might need to send it to the dealer for a proper diagnostic plug in??
  • Like
Reactions: AngelOfMurci
1 - 20 of 20 Posts

· Registered
Joined
·
125 Posts
I had a starting issue with mine a couple years ago. Replaced the battery, was ok for a while then, battery died again. According to the dealer, they found a wire under the drivers seat making contact with something it shouldn't have been. This was causing the battery to be drained slowly.
 

· Registered
Joined
·
6 Posts
Discussion Starter · #3 ·
I had a starting issue with mine a couple years ago. Replaced the battery, was ok for a while then, battery died again. According to the dealer, they found a wire under the drivers seat making contact with something it shouldn't have been. This was causing the battery to be drained slowly.
Thanks for the reply Brian.
Does your Avantador has the start stop? Also, I have the trickle charger on the car when it’s not in use….shouldn’t it compensate the battery if/ when it’s draining?
 

· Registered
Joined
·
125 Posts
Thanks for the reply Brian.
Does your Avantador has the start stop? Also, I have the trickle charger on the car when it’s not in use….shouldn’t it compensate the battery if/ when it’s draining?
It does have start/stop. I was not using the trickle charger at that time. I agree the charger would compensate but maybe not fully keep up with the loss.

by the way, mine is a 14 as well.
 

· Registered
Joined
·
125 Posts
I just found the receipt from the dealer. This is after a new battery had been installed. Here are their notes:

"Battery one cell down. Investigate and found draw. Track down draw to panel fuse and found breaker driver seat over hot. Disassemble driver seat and disassemble side command switches. found harness rubbing short on metal part. Repair harness on side panel switches and put harness in correct plastic guidance. Test and no more draw"
 

· Registered
Joined
·
6 Posts
Discussion Starter · #6 ·
I just found the receipt from the dealer. This is after a new battery had been installed. Here are their notes:

"Battery one cell down. Investigate and found draw. Track down draw to panel fuse and found breaker driver seat over hot. Disassemble driver seat and disassemble side command switches. found harness rubbing short on metal part. Repair harness on side panel switches and put harness in correct plastic guidance. Test and no more draw"
Hi Brian, see when your car couldn’t start, did it come up with the “start stop fault. System not ready” error on the dash?
 

· Registered
Joined
·
14 Posts
It could either be your new supercap is faulty or the ecu that controls the supercap is (GFA- Aerodynamic ecu)
This ecu controls the built in energizing relay on supercap, also could be faulty starter relay located at fuse box
in engine bay,best way to accurately pin point issue is measuring voltage going to starter solenoid/starter main
when pressing starter button provided issue occurs at time of measure.
 

· Registered
Joined
·
6 Posts
Discussion Starter · #8 ·
It could either be your new supercap is faulty or the ecu that controls the supercap is (GFA- Aerodynamic ecu)
This ecu controls the built in energizing relay on supercap, also could be faulty starter relay located at fuse box
in engine bay,best way to accurately pin point issue is measuring voltage going to starter solenoid/starter main
when pressing starter button provided issue occurs at time of measure.
Hello Brian,
If I remove the positive (red) cable from the supercap that goes to the starter motor and connect it directly to the positive terminal of the battery, the car fires up. Basically I bypass the supercap and uses the car battery to start the car. Does this eliminate a faulty starter relay?
Also, does the car needs resetting/ reprogramming after installing new battery and supercap? From previous diagnosis, it seems like the battery is not charging the supercap if the voltages drops in the supercap…..my understanding is that the voltage between the battery and supercap should be a balanced system. The battery should ‘top up’ the dais iron in the event if voltage drop…but I could be wrong…
 

· Registered
Joined
·
14 Posts
Yes that would eliminate the starter relay which supplies the starter solenoid,car will need resetting after
installing new battery,supercap has high amps in it ,it should be discharged using a tool dealers have,
after installing new supercap this tool should be used to introduce voltage back in to it,a new supercap will
be completely discharge,and using tool, voltage should be introduced back in to it,voltage in new supercap should
be at least 2.5 V or more for the battery to start recharging it back.
Yes the battery should top up voltage to supercap after every start up or when voltage drops below certain threshold.
Hope this helps you out:)
 

· Registered
Joined
·
6 Posts
Discussion Starter · #10 · (Edited)
Yes that would eliminate the starter relay which supplies the starter solenoid,car will need resetting after
installing new battery,supercap has high amps in it ,it should be discharged using a tool dealers have,
after installing new supercap this tool should be used to introduce voltage back in to it,a new supercap will
be completely discharge,and using tool, voltage should be introduced back in to it,voltage in new supercap should
be at least 2.5 V or more for the battery to start recharging it back.
Yes the battery should top up voltage to supercap after every start up or when voltage drops below certain threshold.
Hope this helps you out:)
Thanks Brian. I’m getting the car transported to the garage end of this week and they can fault find again (for the 3rd time). Hopefully it’s a case of the ECU being confused and a resetting will solve the issue rather than getting a new ECU/ GFA. Will keep you all posted.
 

· Registered
Joined
·
15 Posts
Signs of the starter motor failing is when the engine crank is slow and takes a long time. Total starter motor failure, you'll either hear nothing at all or just a "click" sound.

When the starter motor is close to failure, you can almost always start the engine when it's cold. However once the starter motor temp increases due to normal engine bay heat, when you turn off the engine and try to start it back up, you'll find the engine crank is slow and takes a long time or sometimes crank once or twice and don't even start at all.

Starter motor failure is quite common as your car approach close to the 10 yr mark. Mine is 2013.
 

· Registered
Joined
·
1,738 Posts
Signs of the starter motor failing is when the engine crank is slow and takes a long time. Total starter motor failure, you'll either hear nothing at all or just a "click" sound.

When the starter motor is close to failure, you can almost always start the engine when it's cold. However once the starter motor temp increases due to normal engine bay heat, when you turn off the engine and try to start it back up, you'll find the engine crank is slow and takes a long time or sometimes crank once or twice and don't even start at all.

Starter motor failure is quite common as your car approach close to the 10 yr mark. Mine is 2013.
I have that issue on my C7 and ordered a shield wrap before buying a new starter.
 

· Registered
Joined
·
27 Posts
Did you get to the bottom of things? Had what i think is a SC failure myself today.

pulled into car wash, then it wouldnt start to leave, bypassed SC and it started fine but i did notice its been getting lazy to start recently, almost like the starter motor was struggling but i think it was the SC starting to fail / get weak, it was a city car before my ownership so assume the stop / start system has had a hard time.

interestingly the SC has an expiry date on top of it which states 2020? if it means the same as normal expiry dates then its done well, any views on this?
 

· Registered
Joined
·
27 Posts
Slow crank could mean heat soaked starter.
it was worse when hot so quite possibly.

anyone have any views on how important the supercapacitor is? and if bypassing it for an hour journey to the garage is likely to damage anything? I figure it just gives a boost to ancillaries to reduce the impact on main battery, completely uneducated guess tho :D
 

· Registered
Joined
·
15 Posts
The SC just temporarily stores electricity to start your engine when you're in Strada Mode (Stop/Start Active).

If the engine start is slow, it's most likely the starter motor that is failing and not the SC.

I drive it in Sports mode all the time so I don't use Stop/Start and it also minimises wear and tear on the Starter Motor.
 

· Registered
Joined
·
27 Posts
Thanks for the explanation, its basically an assist booster for the battery then, the battery itself is quite small for a 6.5l V12..

a failing capacitor also leads to slow start ups apparently as sometimes they dont just fail in an on or off fashion, they can fail to hold charge completely but theres enough to get things started in a ‘lazy’ fashion, then it just gets worse and worse and ultimately dying.

mines been replaced as it took this route, now it starts sharp as a tack.

if you’re experiencing lazy starts then it could be the SC, if you bridge the output possitive on the SC with a second car battery / booster then this will let you know, if the start up becomes like new then you know your SC is on the way out.
 

· Registered
Joined
·
664 Posts
My Aventador broke down in the middle of the street...wouldn't start back up with error on dash "start stop fault and system not ready" stuck in 5th gear.

Ended up being a bad E-gear pump! Part# 470398199 (egear pump motor)
 
1 - 20 of 20 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top