Help needed pls. Parasitic drain on my XC90 V8 ..

[Goldmember]

Hi all,
I have just found out I have a parasitic drain in my V8. Fitted a new Yuasa battery fitted 6 months ago , proper spec etc ) and in the past dew weeks it’s been failing to start if left for more than 2 days . Took V8Bob back to Halfords and they checked the battery and diagnosed with their special gadget that there’ a drain somewhere ( when ignition is off).
Where do I start? Is there anything I can do step by step to help diagnose where the problem is? The car has nothing aftermarket fitted like Audio etc.
Would VIDA be a help as thinking in the near future of buying a setup?
Sorry to sound helpless but I am
Cheers,
Steve

[SwissXC90]

Vida won’t help in active diagnosis but it will help in describing everything.

The easiest way to diagnose is to first understand what uses power when the car is off and check them

Number one culprit is the alarm siren (if fitted)

[Goldmember]

Thanks for your quick reply. It most likely will have an alarm siren.. what’s the best way to check? Is this the job for an auto electrician? Or should I pull the fuse for the alarm? Location of the fuses would help. Ive had 2 earlier V70s 2003/2005 and the alarm siren/modules were always knackered, didn’t know the XC90s were affected.

[gmonag]

It takes a methodical approach to find a draw like this. I suggest watching these and other similer videos for ideas

https://www.youtube.com/watch?v=acdNBBdJWF8

https://www.youtube.com/watch?v=asyR1IzS4LU

[SwissXC90]

You can check a few simple hints as follows

Do the interior lamps and cargo area lamp go off automatically?
They should switch off after about 15 to 20 minutes.
This switching off indicates the car has gone to sleep, and the corresponding UEM resp. REM has shut down.

To test:
Turn on the interior lamps and leave the trunk open for the cargo area lamp to go on.
Take the ignition key out
Close he doors
Do not lock the car
Wait
Check that the lamps are turned off after about 15 to 20 minutes, 5is is when the control modules shut them down to conserve power

You can also test if the CAN bus is properly shutting down:
In the cargo area, access he CAN bus by the REM. I have he rear camera so the CAN bus is readily available.
Use a digital multimeter, and measure normal CAN bus voltage from either CAN bus wire to ground. It will be somewhere around 2.5V. The multimeter will average out the data bus.
Take the key out of the ignition and wait.
The CAN bus will shut down within a minute or so, you will see the voltage change and go high or low, indicating no more traffic.

[Mr.Tango]

You mention "In the cargo area, access the CAN bus by the REM", what is meant by the REM?

Regards David

[oragex]

Try googling for acronyms, for the alarm siren yes, it's better to remove the fuse and see if things get better. It's important to find the problem quickly, because the new battery is getting damaged every time is drained overnight. The best would be to disconnect it overnight but this can cause problems with the climate module temp sensor - may want to have the key in POS II when connecting back the battery

[Harley Dave]

While you are trying to find the root cause of the problem if possible connect an external charger each night to stop the battery getting run down.

If you don't have access to mains power near the car what about a solar panel?

I have one fitted to my car and it keeps the battery near 100% everyday while it's not being used in the current situation.

Cheers

Dave

[gmonag]

Originally Posted by Mr.Tango

You mention "In the cargo area, access the CAN bus by the REM", what is meant by the REM?

Rear Electronics Module
It is behind the panel on the LH side of the cargo area. It is a fuse board with other stuff on it.

[john langrick]

Only by experience, and on an older V70, i found the glovebox was not closing fully and the light in ther never extinguishing.

You might just remove the bulb if you are getting nowhere and see if this makes any difference.

Just a thought