[Spannerhead]

So it poured last night and it's been raining steadily all day (context; not sure if it has anything to do with the car's issues).

Drove to work this morning; everything was OK.

Started car to drive home for lunch, and noticed the following symptoms:

• Seatbelt light on even though belt is buckled
• Somewhat dim OBC, radio and HVAC lights
• No cluster lights or sound for blinkers (but blinkers do come on, as verified when I got home)
• Steering wheel controls for radio (volume, station) inop. Cruise control works fine; light comes on dash, etc.
• Leftmost radio button (the clock/station display toggle) inop

Everything else worked fine, and the car drove perfectly fine all the way home (~15 mi, mixed driving).

I put OBDFusion on it b/c I suspected a failing alternator, but charge was steady at 14.1 while running. 12.4 with the engine off.

SES light is off; no codes.

What's my next move? Open the DME box under the hood and look for loose wires and/or moisture?

Thanks for any and all input.

 

[t3ddftw]

This definitely sounds like an I/K-Bus issue.

You should look at: BMW E46 K-Bus Troubleshooting

 

[Spannerhead]

This definitely sounds like an I/K-Bus issue.

You should look at: BMW E46 K-Bus Troubleshooting

Thanks; very helpful! I'll investigate and report back.

 

[BaliDawg]

Scanning all modules with BMW Scanner 1.4 would give a good perspective on everything affected.

 

[Spannerhead]

Scanning all modules with BMW Scanner 1.4 would give a good perspective on everything affected.

I'll do that also. I recently got a little Windows 10 netbook, so I need to install the whole software suite on that first (I had been running everything natively on XP using an ancient T30 Thinkpad; that's why you had to coach me through the ABS/DSC stuff on the phone last year...).

 

[Overboost]

I would pop out the LCM (2 screws) and have a look to see if it has any water intrusion. My best guess is it has gotten wet from the rain last night. That is usually the first place it happens.

 

[Spannerhead]

I would pop out the LCM (2 screws) and have a look to see if it has any water intrusion. My best guess is it has gotten wet from the rain last night. That is usually the first place it happens.

Popped out the LCM (first time). There was only 1 screw holding it in, so I guess a previous owner had their way with it at some point (?). Wasn't damaged at all; dry as a bone, and no evidence of water intrusion. Smeared some dielectric grease on the connector (it's what I do every time I disconnect anything electrical on the car) and reinstalled. No change.

Once I get my Windows 10 netbook up and communicating with the car I'll check back in.

 

[Overboost]

Popped out the LCM (first time). There was only 1 screw holding it in, so I guess a previous owner had their way with it at some point (?). Wasn't damaged at all; dry as a bone, and no evidence of water intrusion. Smeared some dielectric grease on the connector (it's what I do every time I disconnect anything electrical on the car) and reinstalled. No change.

Once I get my Windows 10 netbook up and communicating with the car I'll check back in.

Copy, it was worth the 5 min to check. Is there any wet carpet inside under the dash? Maybe feel around and possibly pull the glovebox and check the GM5. :dunno:

 

[TobyB]

Dim lighting... hmmm. If you stick a meter on the battery, what's it read? 12.4 is not a fully charged 12v lead acid battery, which
leads me to think maybe you were onto something with the alternator theory...

When a clump of things crop up, it's usually the clump container that's at fault, not the clump...

t

 

[Manolito]

On any modern car, when you suspect a data bus problem, always look to see if there is a phone charger plugged in to the power receptacle. Pull it out and test again. Some phone chargers backfeed their internal frequencies back onto the 12V system, and those frequencies sometimes find their way unto the data bus. A different charger has fixed more than one car with weird transient data bus problems..

 

[Manolito]

Another thought - on my old e36s, computer/sensor problems generally originated with ground problems. The ground on the e36 inner fender, beneath the scanner connector, was troublesome for some reason. The e46s are getting old enough that grounds may begin to be troublesome.

 

[Spannerhead]

Small update:

• Haven't had a chance to remove the glovebox and check the fuse box yet. Will tomorrow.
• I got the suite of BMW tools installed on the netbook and got it to connect to the car. For some reason BMW Scanner wasn't among the tools. @BaliDawg, I downloaded them from your link... Kinda weird. But INPA showed two black circles, so success on that front.
• Measured the voltage at the battery directly: 12.05V. The battery is a little over 2 years old.
• No phone charger plugged in.
• Will check the grounds also.

 

[markusmarkus]

That voltage sez the battery kaput. Put a heavy duty charger on it abs see if it comes back to life.

 

[Spannerhead]

This definitely sounds like an I/K-Bus issue.

You should look at: BMW E46 K-Bus Troubleshooting

OK so I followed the directions on that site and the voltage from the shorting bar was definitely NOT around 12V where it was supposed to be:

Pulled the pins one at a time, testing the blinkers and voltage every time. No change until I got to #7:

Blinkers clicked again, seatbelt light in cluster turned off when belt was buckled, OBC and HVAC displays were normal brightness.

BUT the steering wheel controls for the radio still didn't work, and the radio display was still dim:

Scanning all modules with BMW Scanner 1.4 would give a good perspective on everything affected.

At that point, I plugged in the laptop. I downloaded an installation of BMW Scanner 1.4 but it couldn't communicate with the car for some reason.

However, INPA was able to talk to the car, and when I checked the radio module, it said "No response."

Any ideas? Is my radio dead? What's my next move?

Thanks for all the help. I really feel like I'm drowning with this electronic stuff, but you guys and the resources online are a big help.

 

[Overboost]

Check the amp in the trunk. It could have gotten wet.

 

[BaliDawg]

On any modern car, when you suspect a data bus problem, always look to see if there is a phone charger plugged in to the power receptacle. Pull it out and test again. Some phone chargers backfeed their internal frequencies back onto the 12V system, and those frequencies sometimes find their way unto the data bus. A different charger has fixed more than one car with weird transient data bus problems..

Highjacking da bus!

 

[BaliDawg]

I downloaded an installation of BMW Scanner 1.4 but it couldn't communicate with the car for some reason.

BMW Scanner 1.4 uses its own cable, does not work with the K+DCAN cable.
Read this post: BMW Scanner 1.4 (PA Soft)

 

[Spannerhead]

BMW Scanner 1.4 uses its own cable, does not work with the K+DCAN cable.
Read this post: BMW Scanner 1.4 (PA Soft)

* smacks forehead *

Doh! It's been a year since I've used it, but I should've remembered that. Thanks.

 

[TobyB]

Switch functions on your DVM, there, and measure resistance between the removed wire and ground.

If you get a vanishingly low reading (2 ohms or less, check the little 'range' indicator carefully) yard the radio out and see if it's cut its wiring harness someways.

If it's not quite that low, all signs point to your radio going shitsky. Stuff's 20 years old, and BMW said, at that time,
that the lifespan of the car was 7. But really wanted you to buy a new one every 5.

You can unplug the radio itself and see if you get the same result. If that still fixes it, your radio's in trouble.
If not, it's the wiring to the radio.

hth

t

 

[Spannerhead]

Check the amp in the trunk. It could have gotten wet.

Ding ding ding; we have a winner!

...sort of.

I checked the amp in the trunk and everything was bone dry and perfectly fine, HOWEVER, on a whim, I connected the #7 pin back into the grounding bar at the fuse box, unplugged the Blitz audio adapter I have hooked into the CD changer line and turned the car on.

Perfect. No issues whatsoever.

So I guess the Blitz adapter died, or starting corrupting K-Bus signals, or something.

Guess I need to break down and buy the Avin Avant now if I want to listen to my music...

Thanks again for all the input, guys. I'd be all at sea without you.