tvarghese

Hello All,

I have a 2005 Acura RL with about 175K miles on it. Have had it a few years and recently gave it to my daughter who lives about 300 miles away. She reported the battery dead after leaving in a garage for a week. She rarely drives it. She got one of the lithium battery starters and came down to visit. So I have the car for a couple of days to try and resolve the issue. Being an Electrical Engineer with a few decades of experience with electronics figured this is right up my alley. How hard can it be? Right? Read up on this site about others who have had this issue. HFL, A/C, Power amp, etc. Noted.

Some history:
- I had the Bluetooth HFL problem, fixed it once, came back, so I just disconnected it.

About a month ago, when I first looked at it:
- I disconnected the battery and put the ammeter in series with the negative terminal. Some sparks when I touch the terminals of the meter to the battery (negative) post. Settles to about 0.5A draw. Didn't have time to fix it, she had to get back home for work. Told her to take the terminal off the battery when she parks it for the week. She does follow instructions, usually.

Today:
- Put the ammeter back on it, stronger sparks than I remember from last month and current is draw is over 1A once things settle down. Things appear to have gotten worse! Not good.
- In the Under-hood fuse box removed fuse 22 by removing the two screws and pulling out the fuse. Current goes to 0. Put the fuse back in and screw in the 120A Battery side. Current still at 0. Put the screw on the 70A fuse back and current goes to >1A - Great! Should be a piece of cake now., it has to be in the Passenger side Fuse box!
- Went to the Passenger side fuse box:
- Took out the suspected amplifier 30A fuse, no difference
- Took out all the 30A fuses - no difference
- Took out all the fuses - no difference
- Took out the black square things above the fuses - These may be relays, four terminals, not sure. - No difference!

Any one have any suggestions or thoughts? I have been trying to look through the Service Manual and not finding a good way to figure out the problem. The schematics are distributed throughout the manual so hard to find one or two that might give me some clues.

Could be a wire that has scrapped off insulation and is slowly melting away somewhere between the Under-hood fuse box and the passenger side fuse box. But where to start?

TIA

-T

tvarghese

I disconnected all the wire harnesses coming into the passenger side fuse box. - No diffrence
Disconnected the two wire harnesses near by with the white connectors. - No difference

Also measured the resistance between the battery terminals (without the battery) and seeing about 1 Megaohm, which tells me there is likely not a short in the wires directly between + and -. So more likely some active component that is unhappy or dead and fried.

tvarghese

On a whim pulled out the 15 Backup/ACC fuse in the under-hood fuse box and current went to 0. Not sure what that means yet.
Put all the other fuses and harnesses back, still 0.

Can't start the car that way though So need to dig deeper.

tvarghese

Narrowing down some more... found the schematic on page 22-135 of the service manual. Saw the 40A, No. 15 fuse going to Driver side fuse box No. 7

Pulling the 10A,. Fuse 7 on the Driver's side fuse box seems to help a lot. Initially the current is high (600mA), but after 30 seconds it goes down to less than 10mA.
Progress. But still can't start the car.

Found 22-195 and 22-197 with the same schematic as 22-135, but showing Fuse 7 connected to an "MICU" and "COMBINATION SWITCH CONTROL UNIT". I'm guessing the problem is the MICU.

Thoughts?

Jefftech

So, i am having the same battery drain problem. It takes about 2 days to drain the battery. What did you discover to cure the problem?

tvarghese

Well... my daughter is going to bring the car back around Thanksgiving or Christmas. I have purchased an MICU off of ebay, going to swap them and hope for the best. WIll probably need to copy the EEPROM chip that is on the board before it will work, but that is not really a problem for me, have all the tools to do that

I was hoping she would come back while the weather is still nice. A pain working in a cold garage...

Right now she just pulls the 40A fuse out when she is done for the day/week, she usually only takes it out on the weekends. Lives in the city and uses public transportation if she needs to get around town.

The symptoms sound the same, it does not happen overnight, takes a couple of days. Let me know if there is anything else I can help with, unfortunately, I don't have the car here.

Jefftech

We're going to do some work on this tonight. The current draw is 1.11 between in series with the negative cable and negative battery post. Not good.

I'm wondering if anyone else has had the same problem & found a common culprit.

What is the MICU you mentioned? I'm suspecting the alternator internals at this point. The only other possible culprit is the passenger side door handle which only works when it wants to recognize the keyless auto open feature of the fob.

tvarghese

Yes 1.1A is bad.

Does removing Fuse 7 on the drivers side fuse box make the current go away? If not, it is something else.

Stupid question: Have you tried removing fuses in the fuse box under the hood one by one until the 1.1A goes away? If so, which fuse was it that did the trick? I removed the nuts holding the larger fuses too. See above.

The MICU is inside the gray plastic box underneath the drivers side fuse box.

Jefftech

No # 7 7.5A fuse labelled 'backup' & the others in that row do not reduce the draw.
However the #15 40A fuse labelled 'backup' brings it to zero. I wonder what it is backup to?
We will reposition the car in the garage to get at the other fuse panel inside.

Jefftech

Checked all the fuses on the passenger side fuse box. The 'Illumination' fuse reduces the drain.
Removed the passenger door panel and disconnected the door handle wire, no difference.
Could you forward the wiring schematics to me for further work on finding this culprit?

tvarghese

Can you tell me the fuse #?

I have attached a page that shows ILL on the fuse box. Probably not what you are looking for though.

tvarghese

Adding a couple more pages that may or may not be relevant. Let me know the fuse number and I will look further into it.

tvarghese

So the first MICU I got off Ebay was from a 2006 RL, did surgery and I swapped the EEPROM chip that keeps all the configuration information. Current consumption was down to 35mA, not bad, so I was hopeful.
But it didn't work. I was pretty disappointed and wondered if that was simply not enough to fool the system. Nothing worked, the system came up with errors on SH-AWD,TPMS, AFS, etc. Basically everything was broken. The green key light came on indicating that the Key FOBs were not recognized. I was ready to give up and throw in the towel and pay a ton-o-cash to the dealer. Spent a lot of time on it, see below on getting the connectors off the MICU box... a real pain.

It was really quite a pain to get the connectors off the MICU/fuse box and after all that work really wanted to this to work. If anyone ever attempts this, here is hint: Take off the parking brake pedal and bracket, take the connectors off the front, then take off the cable tie down on the right side, cut off the one on the left, I broke off the slide/latching connectors on the top of the box (couldn't see a way to get them off), then pull the whole box forward ( broke off the plastic on the right side of the box that attaches to metal bracket when i did this, oh well) and then remove the connectors on the back. They are a bit of a pain since you can't see anything and they are tight. My trick was to hold the latch down with my right index finger, slide my left hand from behind and jiggle the connector and wires (GENTLY!!!) until the connector moved enough that the latch was no longer engaged. Then *slowly* continue giggling horizontally until the connector popped off. Start with the connector on the upper right hand corner (from the front of the box) and work you way left. Then start over on the lower row at the right and work your way to the left.

I did this three times and got pretty good at it. I could get all the connectors off in about 30min. Putting them back on took about the same. Not being able to see the connectors made it a bit challenging to get the right connector in the right spot, but... they were all in the right places. So I just grabbed the connector that was lined up with the box and all but one was the right one.

On a whim bought another MICU on Ebay from an older 2005 RL that also built in the late 2004 period like mine. I did notice that the PCB Revision on the 2006 didn't match the original one. This one did. Did the surgery again on the EEPROM chip and voila! It worked!!! I was very pleasantly surprised. Saved me from having to tow the vehicle to the dealer and pay them $165/hr to diagnose and fix it, not to mention the cost of a new MICU, which I'm pretty sure is not cheap.

Battery drain is down to 20mA from over 1A with the broken MICU. Then end of this saga....

Alls well that ends well. If anyone needs to do this, hit me up with questions.

tvarghese

After all this, I had a few moments of panic when I couldn't shift out of park. Turned out there was fuse blown on the MICU/Fuse box unit I had just put in. Replaced it and now things appear to work fine.

huRLingsnow

Thanks for writing this up, guys. I have the same issue.

I'll try some of your aforementioned solutions, but first, some context on the old giRL (177k miles)

The door handle shorted out a couple of years ago, and a lot of problems began with that. There are manual workarounds for all of them, though. We no longer use the key fob. We use the actual key in it. We simply don't lock the driver's side door, and manually lock the other three doors. The #7 fuse remains blown all the time. The nav. screen is out, the front fog lights don't work (despite good fuses and new bulbs), the overhead console does nothing, sunroof is permanently closed, no interior spotlights work - dash and center console,lights all work fine - the AFS light is on (headlights work fine), TPMS lights on as I swapped wheels, and probably some other things don't work. Oh yeah, CD player is done and there's no button push fuel door release. (There's a manual workaround in the trunk, so no biggy.) The car runs and drives like a dream, truly. But this phantom load is getting old. Car lives outside full time.

Keep sharing what you find. I'm sure there are more folks out there with the same issue. Perhaps it is all rooted in the door handle, as someone once suggested.

tvarghese

Yikes! I'm surprised you are putting up with all the crap that has gone wrong with your RL. I guess as long as it still runs...

On mine the only thing that does not work is the HFL. I baked it once (reflow solder to fix a bad connection) and then the next time I tried it did not help. So i tossed that one and bought on off Ebay for $25. It had the same problem, but I didn't try baking it. Decided I didn't need it bad enough.

I"m surprised you can still drive the car with fuse #7 blown, because that is what feeds the MICU and that is what controls the security system. Without this the car won't start or do anything useful. With the wrong settings in the MICU, it will complain about everything (TPMS, SH-AWD, AFS, etc.), engine won't turn over at all. At least, that is what I found. Are you sure it is fuse #7?

If you can find an MICU on ebay, it might be worth trying to replace. If you have a friend that has soldering equipment and is knowledgeable about electronics, have him swap the EEPROM from your MICU into the new one. Since your car still runs, make sure your friend is confident in his/her abilities. It is an 8 pin SOIC chip, relatively easy to remove/replace. Because, if they screw it up, you will have to go to the dealership (more like tow the vehicle to the dealership) and have them reprogram it. Get an MICU that the supplier guarantees will work. The first one I bought (for $50) did not work, the second one ($75) did. The funny thing is that my car was a late 2004 build (model year 2005) and the first one was from a 2006 model year car and yet had a PCB board RevA, while my MICU was a Rev B. I don't know if it makes a difference. But it couldn't hurt to try to find one from a car that is the same model year. I know a lot of stuff is connected to the MICU, I"m sure you can find somebody with electronics experience to help you out on this.

If you do decide to try it, I'd be happy to help you over the internet in whatever way I can. It was a real bear until I found a few short cuts as mentioned in my posts.

Good Luck!!!

huRLingsnow

.....

huRLingsnow

That's awesome! Thanks so much. I have found someone locally who is considering taking it on. I will relay your instructions and see if they really want to go for it.

Re. the 40A fuse - is that the inside driver's side #15 40A fuse you're pulling temporarily?

I'm pretty sure it's the #7 that's unhappy and keeps popping, but I'll verify (after this storm passes). Meanwhile, I'm MICU shopping. I will be in touch!

--

tvarghese

Ok, Just so we are clear, the #7 fuse I'm talking about is the one on the driver side inside fuse panel. If the current does not drop when you pull that fuse, then it is likely not the MICU.

Honestly, I hope it is not. Its a royal pain in the bee hind to replace. But, if it is, I'd be happy to help out even if remotely.

tvarghese

My daughter has the car now, so I can't look to be certain. But pretty sure the 40A fuse I had her pull in the under hood fuse box was #19, which is the "Drive by wire, Laf heater".

My thinking is that since your car still runs, it is unlikely to be the MICU blowing a fuse. Simply because the car just won't run at that point.

I would spend some time tracking down the fuse that causes the current to go down to less than say 50mA. Mine is down to 20mA with the HFL gone. You may need to wait a couple of minutes to get down that far sine there are various things that stay on even after the ignition is turned off.

huRLingsnow

Yep, it's the #7 10A fuse that won't hold in the driver's side fuse/kick panel where the MICU is located. I've yet to verify, but that fuse remains blown, due to my shorted out door handle. That fuse controls, well, too much, IMHO.

But just in case, I called around and tried to find a part number for the MICU. 38200-SJA-A03 is the part number I was told by an Acura parts department employee. Gotta be from an '05-'06. I'm not having a lot of luck finding one, although someone suggested car-part.com, which yielded a nicely searchable way to narrow it down. Still, wording and pics and descriptions haven't left me with much certainty. My FSM says it's also known as "Driver's under-dash fuse/relay box, connector P (MICU)." (from page 22-32 in the FSM.) Connectors B, C, & D are there, too.

Got a part number by chance?

tvarghese

Here are a couple:

This is one, has some broken sections, but it won't hurt anything, I broke the same pieces on mine when I took it out.
https://www.ebay.com/itm/233760051820

I think if you offered this guy $95, I bet he would take it. It is from a 2008, but they claim it is compatible with 2005-2008. If you heard otherwise, might not be worth the risk.
https://www.ebay.com/itm/265254756167

I'll keep looking. I think you have the right part number.

tvarghese

Here are a couple more, I'll limit it to 2005 or 2006 as you had mentioned that is what you heard was compatible:

Way cheaper: https://www.ebay.com/itm/303482850730

A little more: https://www.ebay.com/itm/265444833804

There were a couple more out there, but they seemed like they were from newer vehicles.

huRLingsnow

Ok, I see how this thing’s packaged. Got that one for $30 coming. Thanks for the assistance. I’ve not heard back from the shop I contacted locally. Will keep looking. Cheap fix worth a shot, even if the work is a pita.

—

tvarghese

The hole in the bottom of the cheap one does give me some pause... But if you do get it, see if it has been opened and messed with. Look in the area under the hole an see if there is any damage before proceeding. Or buy both and return the one that you don't use, if they will let you.

Personally, I would look at one of the others even if they are more expensive. After removing one of these things, you will see what a PITA it is and very likely, you will not want to do it again, unless you have to. If you have a lot of time on your hands, that is different. But taking the connectors off and putting them back on while contorting your body IMHO is not worth $50 or even $100. May be you are young and this does not bother you

huRLingsnow

I’m rolling the dice on the cheap one. I’ve found someone who can do the work. He’s highly recommended. So we’ll see if I move fwd. w it after I inspect it.

I’ve built a Toyota Diesel and have always maintained my own cars (mostly TDI VWs). Lots of other stuff, too. I am not young. It’s all beginning to hurt more 😬

—

tvarghese

Ok, so we can't blame youth of this one.

You have done way more than I every have or have hoped to do. Electrical Engineer by trade, so very comfortable around electronics. Was not all that mechanically inclined but picked up automotive repair/maintenance about 10 year ago and learned a lot. It was fun for the most part. Living in the rust belt, taking things apart is not always so easy.. The RL has been exceptional on that front. The 2005 RL has less rust (or rusted parts) than the 2018 Ford Explorer or Subaru Outback.

Ok, so take a look at the unit you have ordered and unfortunately there is no way to bench test it that I know of. So you will have to get it into the vehicle which may not be as difficult for you. But make sure you have a solid two days to do this. You may be able to get it done in one, but you know how it goes on the first try. I'm hoping I can save you from some mistakes.

I case I forget later, the cables with the yellow connectors... the outer shell moves, so slide that up and the rest of the connector should come out easily. Did not know this and I made the mistake of using excessive force and damaged the mating connector. Luckily it was on the bad fusebox, so it worked fine when I put it on the new fusebox. The rest of it is pretty straightforward once you get the parking brake pedal and mounting bracket out of the way. Wires are relatively delicate, you can put some tension on them, but minimize it. On the larger cables it is really not a problem, just the finer ones.

Good luck. Let me know how else I can help you.

huRLingsnow

FWIW, I have found a place locally who, by all accounts, can perform the MICU work needed. I just haven't had the magic combo of free time, good weather, or physical well being (read: back injury) to get it done. But I do get to replace the serpentine belt and tensioner today, as I just found a large metal splinter in the belt and have recently heard the characteristic rattling of a worn out tensioner. This job looks to be much easier than on a TDI, though, where you get to remove an engine mount and all other kinds of awkwardness.

tvarghese

Sounds good.

Yeah, I did this during the summer.

I hope it works out!

Jefftech

Hello again, we did not find the draw & I decided to just purchase a 3-amp battery maintainer rather than pulling the 40Amp fuse.
Everything is fine now.
I am getting a VSA light warning every once in a while though. I hope it's not related. lol

tvarghese

Hmmm.... that is too bad.

I do know that when I swapped out my MICU and it didn't have the right information in the flash it basically lit up all the warnings. I would venture to guess that my MICU was beginning to fail and that eventually it would have started to manifest in things like the VSA, ABS, etc throwing warnings.

It would be good to isolate the problem to least the fuse level. What I have seen some other people do is turn that fuse into a switch and turn it off when you park the car. It's a hack, but simple solution until things get more serious.

Good Luck.

DHeat914

how did you fix the HFL being stuck? i removed the old one and got a replacement on Ebay and its still stuck

tvarghese

I just took it out. Don’t use it enough to warrant the headache.

you could try baking it in an oven like others have done here. It worked for me once. Second time around it did not.