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SOLVED 04 XC90 another parasitic draw

2685 Views 32 Replies 8 Participants Last post by  ORBrickDude
Hang on here with me,, sorry for the long post... Hey guys, kinda new here so please be lenient. I work mostly on German and American cars. This is my second xc90, first was a 2011, current is a 2004 T6. Long story short, when I got the car it needed the CEM repaired due to water damage. Got it done through xemodex. Car started and ran great with a new battery but has srs, brake assist, anti skid and bulb failure messages on dash. Also occasionally has security alarm system message. Driver door window and mirror doesn't work, also won't unlock unless you use the key in the door. Driverside rear door doesn't lock/unlock at all unless inside using the little knob on top. Idk if my DDM is bad or if it's electrical issues causing my multiple driver side door issues. Any advice? But the MAIN ISSUE is I parked it over the weekend and now my battery is dead. When I put the key into the ignition the rear cargo relay RMA3 (for my rear window defroster) clicks like crazy and the power in the entire car flickers and then just dies. Now my battery only has 9.67 volts and the car has no power what so ever. NONE. Turn the key and nothing, no dash, no interior lights, nada. The car makes a buzzing sound from the CEM area while just sitting there that freaked me out so I disconnected the battery in fear and it stopped. Obviously it's getting power but not in a good way...Battery is currently charging, there was no change when I set the charger to jump start and tried to start the car. Same thing happened. WHAT IS GOING ON????? I haven't found any blown fuses yet but I did discover an old blown 10amp fuse near the cargo fuse/relay box laying underneath...no fuses missing or blown in the fuse box. Any help is greatly appreciated.
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Alright here's an update. Tested the car again today and now I'm baffled. I did this twice too. Reconnected the battery, let the car warm up and shut her off. Opened up the hood, trunk and driver door and closed the latches and the car went to sleep. Waited 15min, then carefully hooked up my meter and slid the ground off the battery. Read .002A. I may buy another meter... I then proceeded to pull every single fuse and relay in the trunk, driver's panel, and under the hood. No changes at all. I did that twice. So now I've got a random draw that is sneaky. I decided to investigate around the scm area, looks like someone may have been in there before. I didn't pull the tire but the rivets on the wheel well were drilled out. If they replaced the scm I'd have my alarm sound back correct? I also did some testing on my alternator which was interesting. Not sure if this is normal:
Alt charge cold idle 14.38-14.49
14.40ish warmed up at idle, max and min readings were 14.1 jumped to 15 (voltage went down to 14.1 then jumped to 15 and then evened out around 14.4 again). I tried to do that ACV test and here's what I got: ACV . ~.02-.03 bouncing and occasional jump to .1v don't know if that indicates anything about my alternator diodes. Anybody got a guess or a direction to go next? Posted some pics, that's my wife's hands FYI definitely not mine 馃槀 also if I'm using my meter wrong please roast me View attachment 134946 View attachment 134947
The upper picture shows the meter selected for small battery testing, but seems to be showing DCV. The dial should be turned to DCV, if you are trying for that. The way it is connected could result in the meter popping a fuse, or frying the meter if the headlights or starter were engaged, as the meter is in series with the battery and the load.. To simply measure battery voltage, touch the red lead to the positive terminal and the black lead to negative when DCV is selected and the leads are in the appropriate sockets. There may be a difference in the readings using the other modes.
The meter isn't hooked up quite right in the lower pic. The dial is set to DC 10A, but the red lead is not in the correct socket for that function. The meter seems to be reading mA values, and the red lead is in the correct socket for that function, although not selected by the dial. I wouldn't take it for granted, though. Generally, the extra 10A socket will be for a fuse protected connection. It could be that if the meter is switched to the mA detent, the reading will be the same, except for the decimal places will be moved over.
I looked for a manual for that meter to explore the finer points, but no joy.
It may be a good idea to do a little refresher on using that multimeter. There are many videos available:
Some may have misinformation, so beware, and skim the comments.
There's a thread here somewhere about a poster doing a current draw test, and it covered all the bases well. The big problem is that there has to be enough voltage and current available to lock the car. Accomplishing that is harder than it sounds because all the doors and hatches must be closed and the locks triggered with the remote. Only then will the system go to sleep with one eye open. That may be more current than the multimeter can handle, as all the lights and locks are powered simultaneously when that happens. A possible method would be to string heavier wiring with a switch in it to an open rear window, and the meter wired in parallel to the bypass so that it will read what happens when the baby is put to bed.
I hope this doesn't come across as a "roast", as I still think "every day is a school day" in my senior years. I look forward to new lessons every day!
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That meter has a fuse for the normal functions:
Does the 3320 Auto-Ranging DMM have a fuse?
Yes. The 3320 comes with a 0.315A/250V - UL Listed Bussmann, GMA Type (Radio Shack GMA/270 series; #270-1046 ) fuse.
The info sheet does not say so, but there may be a 10A fuse or circuit breaker in the 10A socket path:
Can the 3320 Auto-Ranging DMM measure DC current (AMPS)?
The 3320 Auto-Ranging DMM will measure 10A (DC from 0 to 10 amperes). Unfused DC current (AMPS). * A waiting period of at least 15 minutes is necessary between every 15 second testing period.

There's not a lot of info on that meter, so maybe the owner's manual would clarify. Just be aware that there may be blackout periods during use for that meter, and if it goes dark for more than 15 minutes that it may be necessary to open it up and replace the fuse. The manual is downloadable, but not anonymously. Pass, for me.

There may still be a problem with the rear hatch open, keeping systems awake. Especially the dome light circuit. Dunno about the '04, but mine dims and times out the dome lights, which is a function controlled by an electronics module (CEM, REM, UEM?). That would be exacerbated by opening doors and pulling fuses. Part of the door-open sensor business is getting a DIM warning. Maybe try closing the switch, starting the car, and checking for open door/hatch messages. Then, maybe try opening the tailgate and closing the hatch to see if there's a message. The problems others have found is having the car truly "asleep" and with lowest current draw when testing.
Otherwise, I would re-visit the battery. New doesn't mean good. Now that you have an isolation switch, charge it well overnight, them flash off the surface voltage by starting the car. Then, shut it off and disconnect the battery. Measure the voltage directly from the terminals, and leave it alone overnight. Then, measure the voltage again. If there is a drop in voltage, continue to monitor it and see if it is the battery itself that is self-discharging. If there is a warrantable issue with the battery, I would pay the difference to get the larger battery that fits, preferably an AGM.
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