Not a Merc - But an interesting thought challenge?

[brucemillar]

Ted

What you describe is what is happening.

We see the charge rise to 14.9 then the THUMP as if something is switched on or off. We then see charging stop for a minute or so, then THUMP!! Charging returns and we carry on perfectly fine.

I will check all earths as per Graeme's post.

I'm also minded to remove the radio completely to rule it out completely.

Remember this started about the time the radio was repaired and the radio sits beside the battery which is brand new.

 

[Ted]

AGM is absorpent glass mat, Bruce.
This has different charge/discharge characteristics to a normal flooded.
The voltages you are quoting are definitely normal for a system that has stop start - may be worth looking out to see what the original fitment was.
The car may still have intelligent charge management but not stop/start - look for an ibu/icu (intelligent battery unit) device on the negative terminal of the battery - it's just a small unit that clamps to the terminal, has a couple of small wires and the main negative cable. This measures battery temperature, state of charge, and state of health. If it has this, you definitely have intelligent charging.

 

[brucemillar]

AGM is absorpent glass mat, Bruce.
This has different charge/discharge characteristics to a normal flooded.
The voltages you are quoting are definitely normal for a system that has stop start - may be worth looking out to see what the original fitment was.
The car may still have intelligent charge management but not stop/start - look for an ibu/icu (intelligent battery unit) device on the negative terminal of the battery - it's just a small unit that clamps to the terminal, has a couple of small wires and the main negative cable. This measures battery temperature, state of charge, and state of health. If it has this, you definitely have intelligent charging.

Ted. It has this. At least it has a largish 2" square plastic top with some electrickery in it. This sits on the +ve terminal. This then feeds to (what eBay calls a) voltage regulator board. This is a box of high voltage links with big fused connectors.

 

[grober]

He means AGM battery [Absorbent Glass Mat ] I believe they need a slightly higher voltage to charge efficiently which might explain your 14.9volts??
TOO LATE.

 

[brucemillar]

Hmmm. Not my post, but taken from the BMW forums. This is for the same age X5 as mine.

An e53 X5 doesn't require battery registration. Your X5 falls on the "old" side of things...prior to the newer LIN & BSD communication bus systems used on BMWs since the new generations started (e90/e65/e60/e70/etc).

Your e53 X5 DOES NOT have an IBS (intelligent battery sensor) nor the LIN or BSD bus where the battery, alternator, and DME are in constant communication of each other.

The IBS started with the e60 5 series and every model that debuted after. The early e90 & e65 models that debuted before the e60...still need battery registration due to communication over the LIN and/or BSD bus...but again, these 2 models are new generation BMWs.

And don't let folks at the local BMW dealership rip you off either...I've read enough threads where owners of e38s/e39s/e46s/e53s have been told & charged for battery registration on these older models...and it is NOT needed. Just swap in your new battery and go.

 

[Ted]

Thanks Bruce - looks like I was barking up the wrong tree there then - apologies, but worth keeping an eye on those to see if they are on overrun/power.
Back to my Talisker then

 

[brucemillar]

I'm going to remove that radio from the boot completely.

 

[brucemillar]

Ted

Here is where my brain is at on this.

1. I think Mrs M had a point when saying "it's like it's meant to happen"

How about this.

It is working as designed. But, my repaired & upgraded radio (he uprated the output channels) NOW reacts to the power cycle by allowing current to 'crossover' in the bus somehow. That crossover is read by the brain as a disable command. The next THUMP is read as 'switch back on, or, enable'

I know that the radio acts as a conduit in the bus loop. So it is possible that it is sending false / true signals down the line to the brain.

Mad?

 

[Ted]

Bruce, I get that the radio may be 'overreacting' to the voltage changes.
I agree - remove the radio is the next step - I'm sure Mrs M can sing to herself for a couple of days, and if this resolves it, then substitution is the way forward.

 

[brucemillar]

The radio unit is now out of the car.

This has removed the whistle that was rising & falling in pitch with engine revs/alternator speed.

I took the opportunity to re-check all the wiring that I can see for damage? None found.

Tomorrow I will drive the same route, without the radio. Let's see what happens?

I will fit some braided earth to the radio and body earthing point when refitting. Currently I have no external visible radio earth.

 

[brucemillar]

Today's update, brought to you by our roving reporter from a cold and damp Kent morning.

With the radio completely removed from the car, The problem has disappeared. I can see the voltage rise sharply at the 10 minute mark, then it drops down as the alternator switches on/off "as designed". Crucially there are no errors being displayed during the Voltage cycle and the car is not dropping a gear or flaring the revs.

So.... The radio is the culprit (at this point in time). I am sending back to the company that repaired the output stages on it. They have happily agreed to look at it agin for me.
At Ted's suggestion. I will first try fitting a braided earth from the radio body to earth. Whatever the radio is doing? It is picking up alternator whine/whistle. My guess id that that it picking up noise that it amplifies somehow into the bus. The brain then reads that noise as inputs/errors?

My thanks (as always) to the Wonderful Ted. Who has kept with me here on this and probably wishes he had hid behind the sofa.

 

[brucemillar]

Well, another day in the madhouse.

Please bear with me. You might like this. The day started with a telephone call to Carphonics. This is the company that repaired my radio. I explained my issue and they told me they have see several X5’s with strange electronic faults, including phantom gear shifts and erroneous errors, caused by “re routed boot wiring” hmmmm. They offered to take the car and me and substitute whole units etc to try and diagnose this.

Another call between myself and Ted (from here) and I decided to earth the radio body to the battery earth. Wow, this caused an immediate high volume alternator whistle. Disconnect the earth? Whistle drops to the usual low level.

Next I separated out the radio wiring from all other wiring and routed the battery earth around the other side of the battery (not the manufacturers side)

So. Test drive begins.

No whistle or whine and no errors.

Tomorrow we will repeat.

If this proves to be the cause? Then it is caused by the battery earth noise cross talking with the radio and bus.

Fingers crossed please.

 

[Codger49]

Fingers well and truly crossed.

 

[Jkh112]

Thanks for the update. Waiting to read the next instalment. My fingers are crossed for you.

 

[brucemillar]

AAAAAAAAAARRRRRRRRRGGGGGGGGGGGGHHHHHHHHHHHHHHHH ROLLOX SHYTE DAMM & BLAST

Started engine at 7:43 drove up the M2 and at 7:53........... THUMP - Suspension Inactive / 4x4 Inactive - THUMP - All Errors Clear.

What I did notice on the drive: The alternator whistle/whine is back again via the speakers? Not as loud as before, but it is there again. It is possible that a wire may have moved in the boot as I did not tie them all down in their "new" routes, to help with diagnostics.

Sow what do we know?

* With the radio out the car. There is no issue at all. No thumps, no errors. All is as designed except we have no radio.

* The radio is transmitting alternator whine/whistle. I can "correct" this by moving the battery earth/radio wiring away from one another.

* It is not 100% conclusive that the radio (Becker BM54) is the culprit or the victim? Why?

* There is also an Alpine Amplifier that sits on the same loop and is powered by the ignition AND the radio being in place. No radio = no amplifier.

** The fault was not present when I bought the car.

* I have replaced the battery with brand new Yakusa Halfords Battery that was matched to the car chassis number.

* I have repaired a faulty Suspension air compressor that had a damaged live feed (I just insulated it) and a worn piston ring (I replaced it).

* Repaired the output transistors on the radio and added a aux/bluetooth lead. *** This is when the whistle/whine started!!!!!

* If I disconnect and remove the aux lead and bluetooth receiver? I still have the whistle/whine and the errors.

* If I remove the radio? I cure the fault.

I have no option now, but to try another BM54 Radio Unit and see if this fixes the fault.


My thinking is that the THUMP is the result of the battery/alternator switching as the car reaches optimum charge/performance. That is happening 10 minutes after first start of the day. That THUMP is being read by the brain as noise causing the brain to throw out a series of errors. I now know that all of the errors that we see would "normally" be triggered by voltage switching. With the radio out of the car the switching is still happening. I can see that by leaving a voltage display on the cigarette lighter socket. So it still switches but does NOT cause any errors. Put the radio back in and we get the errors back, every time. It is repeatable on a daily basis and will only happen once a day at the 10 minutes after first start. (Maybe fairer to say, we only see it happen then)

 

[grober]

Remember that BMW [ like Merc] has several CAN BUS systems not just one --often running at different clock speeds. What all the electrical systems /units share in common is the 12 volt power supply alternator and battery

 

[brucemillar]

Remember that BMW [ like Merc] has several CAN BUS systems not just one --often running at different clock speeds. What all the electrical systems /units share in common is the 12 volt power supply alternator and battery

Graeme

Yes his is very true. The ten minute after first start is now "proven" I would say 99% of journeys we get the THUMP then the errors at that ten minute window. This is timed using the cars digital clock and is not related to "time of Day" but is related to first start of the day. Now we know that the car does a health check every 6 hours regardless of key in or out and that this is a cyclic six hours!! So the battery will try to recover some lost power after first start.

What I can find suggests that what we see is "normal" in terms of the voltage increase/decrease at the 10 minute window. But something in that voltage switching is being transmitted by the radio via the bus to the brain. The brain cannot decode it so chucks out a set of "default" errors, all of which relate to voltage spikes +/-

The THUMP is the trigger for the errors, and the THUMP is, being triggered by cars normal charging cycle/switching. I think that the radio is not suppressing the THUMP either because it is faulty or I need to somehow isolate it from the battery. The latter is not very easy as the harness is tight and both radio and battery share the same location under the spare wheel, in a well. In the same well you have the air suspension compressor and electronics and the main electrical harness. Basically BMW designed the car to have all the electrics in the boot, under the floor, along side of the battery.

I start to think that this is more to do with a hardware failure on the radio than a wiring/cross talk/interference issue. I cannot believe that just moving a radio or a pump would induce such a catastrophic set of errors. To get them to fit back, you have to refit the harness "as was". When we bought the truck the radio had no sound output. This is a common fault on the BM54 that blows the outputs due to overheat or water ingress into the boot, from the sunroof drains. I do not have a sun roof and no evidence of water ingress (I sprinkled talc and hosed the car to test). The radio fault was proved by installing another unit. Then repairing the outputs (done by Carphonics, who know there stuff). Since then I have had the whine with the THUMP starting much later.

If I had a spare Radio I could prove it now.

 

[brucemillar]

So out of frustration and stubbornness (a word that looks badly spelt but it is not) and not wanting to kick the dogs or the wife. I took everything apart, and I do mean everything. I stripped the boot and moved components one at a time to try and isolate the whine and find any clues to anything that may cause the THUMP.

There is nothing obvious. So that is good in one sense but frustrating in another. What I can see is that all of the wiring is "factory fresh" no choccy blocks or soldered connectors, no insulation tape or twisted pairs. That, I feel is very good news as I am looking at a vanilla build and do not need to get drawn into what other things did, or do.

What I also found is (unlike what I was told) the Becker Radio (BM54) and the Alpine Amp work as a pair and are dependent on each other for sound output. So I cannot remove the Alpine Amp or patch the wiring harness to the Becker so that I can have sound without the amp, thereby allowing me to pinpoint if the amp is at fault?

The amp and the Radio do not sit next to each other (I suspect by design to avoid cross-talk?) The amp is buried under the NS rear light cluster in the arch well, and under the NAV, CD etc.

The Radio is buried under the Spare Wheel, Air Suspension Pump and next to the Battery, as in 1" from the battery. It is uber sensitive to the battery earth. If I move the radio .5" away from the battery the whistle stops!

Now here comes the dumb bit: To enable easier diagnosis and not to keep pulling the car apart each time I needed to access the radio? I had left off the plastic floor cover for the radio!! I now find that with the battery earth routed around the rear of the battery (where I had previously moved it too) and the cover back in situ. The whine is gone. So that cover must proved some screening. But I also start to worry that my new Halfords Yakusa Battery may be noisy? How can I tell, other than try another battery?

I then moved onto the Alpine amplifier. To remove it, you must remove the skin from your hands and lower arms. But it eventually came out. It shows no signs of ay obvious damage, in fact it looks brand new. It is a black tin box with a mahoosive heat sink and single multi-plug. The circuit board sows no sign of the (BMW Forums water ingress from sun roof drains etc) and nor did the surrounding floor area. On closer inspection I did find some very small metal scrapings inside the multi-plug connector on the amplifier. I have no idea how they got in there? but I blew it all out, with an air line and switch cleaner.

On reassembling/refitting the amplifier. I found that the connector loom was very tight, allowing very little, if any movement, to get the amplifier back into place. This also explains why it was so difficult to remove. A look up, the harness revealed that it was crushed between the car body and the mounting frame for the Amplifier. This is big harness 30+ wires. When I loosened the 'offending' frame I could see that it has a rubber protection cover around a large cut out, where the harness "should run" I can now see that the harness would never have been located correctly (since manufacture) as the rubber has absolutely no sign of any wire pressure that would be evident after 10 years. It is also evident that the loom was being crushed, but had not been cut or badly chaffed (phew). I have now routed the loom and re-fitted the frame/chassis correctly.

**NB** You may recall that this is the second bit of wiring damage I have found that must have happened at manufacture, having previously found the live to the air compressor had a 6 inch long bolt pierced through it. That had not earthed as the bolt was mounted on rubber shocks at either end to provide noise reduction for the compressor pump.

Anyway it is all (once again) back together. A good run out, yesterday revealed NOTHING. No THUMP, no Whine/Whistle and no Errors. I remain unconvinced that I fixed it. Time will tell. If not fixed then I will have to bite the bullet and return to Carphonics who have kindly offered to swap in replacement radio, amp etc. The issue being that it only happens once a day and after ten minutes. What I really want then, is to just replace the Becker and the Alpine together and try that. Otherwise I will be driving up and down to Enfield all week, which I do not need.

Fingers Crossed.

 

[RichardF]

Hope it works, maybe a pinched wire, not a fibre optic bus system is it?

 

[brucemillar]

Hope it works, maybe a pinched wire, not a fibre optic bus system is it?

Richard. Thank you. No it is not Fiber. Good old fashioned coloured wiring wrapped in the stickiest cloth tape, since Mr Sticky, the sticky man, decided to make some sticky stuff. Christ it gets everywhere and attracts dirt & dust, paper, pubic hairs, all sorts.