2007XC90 Battery is draining 3amp (Bad ALT Diode) Topic is solved

ilkerk · Post by **ilkerk** » 28 Dec 2017, 15:07

Hello all,
I have a 2007 XC90, which is draining about 3amp when car is turned off. After few hours, car doesn't start without a jump start. I tested the current draw before and after removing each fuse (and the relays in the engine fuse-box). Still draining the same amount regardless.

I want to check whether alternator causes draining before taking to a mechanic. Is there an easy way to check this? I couldn't locate the wiring from/to the alternator.

Also, I saw in an online manual that other than the 4 main fuse compartment there is a 5th one referred as "fuses by the battery".
Below is a picture of it:
These fuses supply DC to each of the fuse boxes. Anyone know if is it safe the remove each one of these and check for the current drain? Since these are not removable like the regular ones I have to remove the bolt of each one.

thanks.

Post by **precopster** » 28 Dec 2017, 17:05

Which engine series is fitted? Is this 3.2L 6 cylinder or V8?

Best to disconnect battery then fit ammeter in series then connect battery so you can measure the current draw. If you don't do this you risk getting unclear-able SRS messages.

3 amps is a lot of drain. I once had a 4A drain from a faulty alternator regulator. You can remove large red lead from alternator and see if current draw is still there.

ilkerk · Post by **ilkerk** » 28 Dec 2017, 17:19

It is 3.2L 6 cylinder model.
Yes, it is a lot of current which drains battery in a few hours.
I already got an SRS Airbag error message. I was thinking this is because I forgot to put back one of the fuses...
(I havent played with the "fuses by the battery"). Is that a bad news?

I will try to find the large red lead and test after removing it as you suggested.

Thanks for the info.

Post by **precopster** » 28 Dec 2017, 21:13

If you have SRS messages you'll need to clear it with a Volvo compatible scanner or dealer. Let us know if disconnection of the large red lead stops the current draw.

ilkerk · Post by **ilkerk** » 29 Dec 2017, 16:25

I think I will deal with SRS message later since now I even can't start the car. But I got my lesson about procrastinating the issue.

I couldn't locate the red cable to the alternator. Alternator is difficult to reach in XC90. However, there are two red cables connected in the engine fuse compartment. May be one of those is going to the alternator?

Today I couldn't jump start the car so took the battery to a nearby mechanic. He said the battery was damaged from the cold ( it is -20C here) and he said the current drain was probably due to the damaged battery. I was happy for an hour with that possibility. But when I placed the new battery, the current draw was even more, it was changing between 5amp-6amp. I believe that is a shortcut.

I disconnected the battery. Tomorrow I will remove all the fuses and relays and the red alternator cable if I can find it.

best,

Post by **precopster** » 30 Dec 2017, 00:01

Just had a look at Vida and it explains the procedure of removing the regulator from the B6324S engine in the following steps:

Remove the following items:
battery negative lead.
Refer to: Battery, disconnecting
the intake manifold.
Refer to: Induction pipe

Then there are 4 X M4 screws to remove the regulator

The attached document explains manifold removal

ilkerk · Post by **ilkerk** » 30 Dec 2017, 14:44

precopster thank you so much for the information. I couldn't try as now seems even bigger problems with the car.

Today when I removed all fuses and relays at the same time, the current drain dropped to 0.2amp. I had to remove the fuses together (not one at a time) to detect the ones that are causing current drain:
- ceiling lighting and upper electronic control module
- moonroof
- Rear AC
- Rear electronic module

I remove those 4 and turn the key. Nothing happened, just a sound from engine (like a pumping sound). Engine light is ON and I have a new error message Anti-skid service required.

Can these be because I removed the fuses of electronic control module?

The car getting worse everyday, nearby mechanic will be open on Tuesday. Sighh...

Post by **abscate** » 31 Dec 2017, 06:28

Where are you measuring the 3A drain?

I would check the drain at the left most red wire, the feed wire to the fuse box breakout , to isolate the drain. Ypu Can then check each feeder for drain.

Remember, remove neg cable. Wait 15 minutes

Then loosen each nut, Polish clean, and hand tighten for testing. Take each one-off, then use the ammeter to check in series. Don’t forget to connect negative before testing!

Once you disable a module on a can Bus Car, all bets are off on function...everything talks to everything else, mostly.

ilkerk · Post by **ilkerk** » 01 Jan 2018, 12:34

abscate thanks for the message.

3amp reading was when I disconnect the negative wire to the battery and place the ammeter in between.

Today when I put double checked the fuses. I tested each cable connection above. Total drain was 5.60amp. Below are each readings. Looks like the last one draining a lot. But all are much higher than the desired 0.02amp.

1st 5.60amp main connection to battery
2nd 0.73amp Rear Electronic Module (REM)
3rd 0.83amp Fuse in cargo compartment auxiliary fuse box
4th 0.45amp Central Electronic Module (CEM)
5th 0.00amp Fuses (1,3-6) in the passenger compartment
6th 3.63amp Fuses (2,9-14) in the passenger compartment

Post by **precopster** » 02 Jan 2018, 14:23

Follow the red cables to where you will find 2 connector blocks close to the REM under the removable foam corner pad. Check the connector blocks on the red cables for corrosion.

I'm assuming that ignition is turned OFF with the current draw readings you're getting?

Also on the CEM you can pull the green cable hold and remove the main power feed going into the CEM. After doing this you can retest the current draw.