Battery drain / Nav unit always on
 

Hi,

I’ve done quite a lot of searching on here and the web generally and there’s a few related posts and many more that mention this is known problem… but not sure I’ve really found a solution yet.

So I have a 4.8is with widescreen nav, CD changer swapped out for a GROM Bluetooth unit instead and also an additional amp and sub added (wired to come on with remote power connection on the E53 alpine amp).

This setup has been in place for several months, and I’ve had no problems. Earlier this week though I noticed the GROM Bluetooth unit was staying on after I had parked up (even hours/days later). I only noticed as my phone would keep connecting to it which was quite annoying.

Earlier today, battery was of course completely dead. Couldn’t even unlock the car … so I’ll probably end up having to buy another new battery (replaced only a few months ago also).

I’ve put the car on a CTEK to charge/recover the battery but also has a quick poke around and noticed that the red light on the mk4 nav unit never seems to go out which seems abnormal to me.

I think the car is going into sleep mode (no light on the gear shift) but I can’t be 100% sure.

Any ideas what could be causing the nav unit to stay on? Any ideas on a fix for this?

Bit odd that this should happen now, car had been sat for weeks unused without a problem before I used it for a trip earlier this week.

Finally had some time to try and dig into this a little further.

The car definitely goes to sleep (orange light on gear shift next to P goes out) and the nav unit is definitely staying on permanently.

I measured drain, once the car sleeps it dropped to about 0.65A (with the nav unit red light still on / blinking).

I disconnected the mk4 DVD nav and then it drops to 0.2A and stays there. I tried pulling other fuses (72,73,74,75) for the audio/ telephone/nav modules but the current didn’t drop any further.

Is 0.2A about right or does this seem high still?

I guess I can try and replace the nav module but I’m guessing its possible something else is keeping the nav awake and the nav is actually fine?

The current draw shouldn't be more than 40 mA when the vehicle is in sleep mode.

Nav module is woken up by I-bus.

40mA. Bah, way over that right now then at 200mA.

Guess I need to figure out what the heck else is staying on then. Could be anything else on the iBus I guess?

So is the GROM BT module also powered by separate activated supply? Or have you tested the obvious and disconnected that BT module?

Just did this test myself. It takes 16 min (advertised) to go fully to sleep. I secured my meter between ground wire and post by the fuseable link box under the trunk floor on the left side (didn’t want to pull my air compressor again). Then I propped it up so I could read it with the trunk lid closed and closed and locked the car. Hack your watch and wait. It goes down in a couple small increments, as I assume boxes go to sleep, but at right about 16 min the current dropped significantly to between 40 and 50 milliamps.

If it doesn’t go to sleep fully, then pull a fuse to a likely suspect and repeat the above process. I read that the phone and nav tend to cause these problems.

The Grom is powered by the connections for the original CD multi changer.

I did disconnect the Grom, but I didn’t wait the 16mins to see if removing it allowed other things to go to sleep, so I guess I need to try and do that now.

Thanks, this is exactly what I did too (though I removed the air compressor anyway but then realised I didn’t need to).

I did pull several fuses, BUT, I didn’t wait the 16mins, so it could be that something on those fuses was sending iBus messages and keeping something awake… so I guess I need to go back and do this again and wait 16mins after pulling each fuse too.

More weirdness.

I left the car on the weekend with the nav unit removed. Car went to sleep, bluetooth on the GROM disconnected from my phone. Seemed ok(ish) with a somewhat high draw but at least the GROM was turning off correctly.

Last night, so several days later, the GROM woke up. I noticed because it seems pretty aggressive in connecting to my phone and even when I’m in the house it will connect to the GROM and I lose my audio which is quite annoying but right now I guess useful too as it alerts me to some weirdness.

So what the heck is causing the GROM, which I guess to the car is just a CD player, to wake up several days later and stay on (its still on right now).

I don’t have the ammeter connected anymore so can’t see the current draw unfortunately but I’ve ordered a Bluetooth connected ammeter with data logger so I can leave it connected with the car again for a few days.

I guess maybe the GROM has become faulty?

Aaand a day later the GROM Bluetooth is off again without being touched.