E38 radio issue - no power, no sound, no display

[Technik333]

I have a 1996 pre-LCI E38 with DSP (the massive black amplifier), 4:3 screen at the front, CD changer, analogue tv tuner and a radio unit (C23). My radio is not currently working and the screen is completely blank, no orange lit up. I checked all the fuses, powers are going through the radio unit (tested the fuse), CD changer and the DSP amplifier however no signal from the i-bus when i plugged into my OBD scanner. Any ideas what is causing the problem?

[jpilk99]

Don’t know if our issues are the same but they sound similar. My widescreen won’t work (tho the buttons light up and eject works). Tried a “new” Nav, that worked for 2 seconds ...then the display disappeared- no sounds. Next up is a new C43 radio unit in trunk. Then a new widescreen...

Let me know how you progress please. I may learn from you.


Sent from my iPhone using Tapatalk

[Technik333]

My situation is more severe - the radio unit won't power up at all and the power button doesn't lit up. I can hear the amplifier is running when I turn on the car, power is going through the C23's fuse. I suspect it either the i-bus is not sending signal to activate the radio given my E38 is fitted with DSP or the C23 unit is faulty. I'm currently looking for a 2nd hand C23 unit to test whether it would fix the problem and my next step would be the amplifier, then probably have to check out the LCM module in the footwell as it controls the i-bus.

[jclausen]

I would check for power to the radio first

[Mayorchuck]

My situation is more severe - the radio unit won't power up at all and the power button doesn't lit up. I can hear the amplifier is running when I turn on the car, power is going through the C23's fuse. I suspect it either the i-bus is not sending signal to activate the radio given my E38 is fitted with DSP or the C23 unit is faulty. I'm currently looking for a 2nd hand C23 unit to test whether it would fix the problem and my next step would be the amplifier, then probably have to check out the LCM module in the footwell as it controls the i-bus.

That would be my first step as well. I have no experience with your setup but on the early E38's, the radio is the head unit and is often the issue.

[Technik333]

There are power going to the radio as I tested the fuse with my multimeter. I'm currently sourcing a replacement radio unit, will keep you posted to see whether it'd fix the problem.

[Technik333]

Just a quick update, I've swapped a replacement radio unit unfortunately didn't fix the issue - still cannot switch on the radio, no orange light lit up, screen is blank and nothing is functioning other than the DSP is running in the background.

- - - Updated - - -

Have just read this thread https://www.bimmerforums.com/forum/s...2001-E38/page2

Might try to check the LCM module whether any power going through the i-bus signal and KL-R as what ted has suggested (t3ddftw)

[Mayorchuck]

Have you had any issues with water in the cabin? One of the signs of water in the fuse block under the passenger seat is radio issues. That area also has many splices and grounds. They sit in the lowest area of the floor pan so it doesn't take much water to cause issues. Clogged sunroof drains cause water to flow down behind the A pillar to the floor, with an occasion stop in the glove box. fuse.jpg

[t3ddftw]

Just a quick update, I've swapped a replacement radio unit unfortunately didn't fix the issue - still cannot switch on the radio, no orange light lit up, screen is blank and nothing is functioning other than the DSP is running in the background.

- - - Updated - - -

Have just read this thread https://www.bimmerforums.com/forum/s...2001-E38/page2

Might try to check the LCM module whether any power going through the i-bus signal and KL-R as what ted has suggested (t3ddftw)

For what it's worth, the I/K-Bus is an active low bus, meaning it should read 0v if a module is "speaking". It idles at 12v. There's a junction terminal that you might be able to use to disconnect individual modules from the bus until you find the culprit: https://bmwteka.com/wds/en/e38new/5bf9bb9d

-Ted

[Technik333]

For what it's worth, the I/K-Bus is an active low bus, meaning it should read 0v if a module is "speaking". It idles at 12v. There's a junction terminal that you might be able to use to disconnect individual modules from the bus until you find the culprit: https://bmwteka.com/wds/en/e38new/5bf9bb9d

-Ted

I have already disconnected the following:

-6 CD changer
-TV tuner
-Telephone transmitter.

I have checked the K3 and X57 in the LH side of luggage compartment with my fuse test light - all working fine.

https://imgur.com/IXMIJoN

I swapped my old C23 radio tuner to an old BMW headunit, power is going through the unit and I can hear the DSP is running however cannot hear any sound as I suspect the i-bus is not feeding signal at all. I have a spare 16:9 screen display swapped it with the original 4:3 screen, didn't solve the issue neither.

https://imgur.com/a/dF4VQ5N (Please turn on your sound!)

Ok I'll check the x939 connector, is it located in the glovebox (for RHD)?

- - - Updated - - -

Have you had any issues with water in the cabin? One of the signs of water in the fuse block under the passenger seat is radio issues. That area also has many splices and grounds. They sit in the lowest area of the floor pan so it doesn't take much water to cause issues. Clogged sunroof drains cause water to flow down behind the A pillar to the floor, with an occasion stop in the glove box. fuse.jpg

I didn't have any other issues with the LCM module, all lights, hazard lights, turn signals, instrument cluster are working fine - just no signal from i-bus for the onboard monitor, radio, MID etc. I'll take out the front seat and pull the carpet to check out the fuse block then.

[t3ddftw]

I have already disconnected the following:

-6 CD changer
-TV tuner
-Telephone transmitter.

I have checked the K3 and X57 in the LH side of luggage compartment with my fuse test light - all working fine.

https://imgur.com/IXMIJoN

I swapped my old C23 radio tuner to an old BMW headunit, power is going through the unit and I can hear the DSP is running however cannot hear any sound as I suspect the i-bus is not feeding signal at all. I have a spare 16:9 screen display swapped it with the original 4:3 screen, didn't solve the issue neither.

https://imgur.com/a/dF4VQ5N (Please turn on your sound!)

Ok I'll check the x939 connector, is it located in the glovebox (for RHD)?

- - - Updated - - -



I didn't have any other issues with the LCM module, all lights, hazard lights, turn signals, instrument cluster are working fine - just no signal from i-bus for the onboard monitor, radio, MID etc. I'll take out the front seat and pull the carpet to check out the fuse block then.

Can you possibly get a multimeter and check voltage at the purple/white stripe wire on the radio connector? It needs to be 12v.

I just did some testing with my bench components and found the following:

1. The Radio responds to the On/Off commands as long as KL-R is active, even if the Navi is off.

2. If the I/K-Bus is pulled to ground, then the Navi doesn't even attempt to boot and the monitor stays pitch black.

3. If KL-R is not active (12v), then the radio does NOT respond to the On/Off commands

This leads me to believe that the I/K-Bus is probably fine and there's possibly an issue with KL-R at the connector end of the radio.

EDIT: My hypothesis doesn't account for the Navi not booting, though... Maybe the cluster isn't realizing that the key is in and sending the I/K-Bus message for ignition as well? If you PM me, I can let you borrow one of my BlueBus modules for testing this hypothesis.

Hope this helps!
-Ted

[Technik333]

Can you possibly get a multimeter and check voltage at the purple/white stripe wire on the radio connector? It needs to be 12v.

I just did some testing with my bench components and found the following:

1. The Radio responds to the On/Off commands as long as KL-R is active, even if the Navi is off.

2. If the I/K-Bus is pulled to ground, then the Navi doesn't even attempt to boot and the monitor stays pitch black.

3. If KL-R is not active (12v), then the radio does NOT respond to the On/Off commands

This leads me to believe that the I/K-Bus is probably fine and there's possibly an issue with KL-R at the connector end of the radio.

EDIT: My hypothesis doesn't account for the Navi not booting, though... Maybe the cluster isn't realizing that the key is in and sending the I/K-Bus message for ignition as well? If you PM me, I can let you borrow one of my BlueBus modules for testing this hypothesis.

Hope this helps!
-Ted

Thanks for getting back to me quickly. I checked the voltage at the purple/white stripe wire on the radio connector with my multimeter, it was showing 12.57v (because the car is currently on tickle charger)

https://imgur.com/a/htfscNr

I have already unplugged pretty much everything including the x400 connector for the phone. I've left the x322 connector plugged in unfortunately still no signal to the Navi (the 4:3 monitor screen) other than the DSP running in the background.

https://imgur.com/3bmtWSe

I have also plugged in to my scanner, it is showing the radio working but currently switched off.

https://imgur.com/maTX1L6
https://imgur.com/kJJawj5

[t3ddftw]

Thanks for getting back to me quickly. I checked the voltage at the purple/white stripe wire on the radio connector with my multimeter, it was showing 12.57v (because the car is currently on tickle charger)

https://imgur.com/a/htfscNr

I have already unplugged pretty much everything including the x400 connector for the phone. I've left the x322 connector plugged in unfortunately still no signal to the Navi (the 4:3 monitor screen) other than the DSP running in the background.

https://imgur.com/3bmtWSe

I have also plugged in to my scanner, it is showing the radio working but currently switched off.

https://imgur.com/maTX1L6
https://imgur.com/kJJawj5

Great! Since KL-R is active, and your cluster is operating normally (right?), my assumption is that the 4:3 died. The 4:3 is in charge of sending the message to the radio that it should turn on (it does so over the I/K-Bus).

I recommend upgrading to the 16:9, but that would also require that you replace the TV Tuner with a real Nav computer (I'm 99% sure the OG video modules can't handle 16:9) -- might as well go to the MKIV.

Here's the best deals I could find on a 16:9
https://www.ebay.com/itm/164571981220
https://www.ebay.com/itm/164369108800
https://www.ebay.com/itm/264997898973

If you want to stick with the 4:3 -- https://www.ebay.com/itm/283504148116

I couldn't find any stellar deals on a MKIII or MKIV Navi. (i.e. a MKIV for $100 or < $60). I do have a spare MKIII that I can sell for $60 if you're interested.

The C23 will work with these components, but I would suggest grabbing a Siemens CID radio from an E8x and following Frankie's guide on shoe-horning that into the E38 (http://www.frankies-bmw.com/7series/...emens_prep.pdf)

Thanks!
-Ted

[Technik333]

Great! Since KL-R is active, and your cluster is operating normally (right?), my assumption is that the 4:3 died. The 4:3 is in charge of sending the message to the radio that it should turn on (it does so over the I/K-Bus).

I recommend upgrading to the 16:9, but that would also require that you replace the TV Tuner with a real Nav computer (I'm 99% sure the OG video modules can't handle 16:9) -- might as well go to the MKIV.

Here's the best deals I could find on a 16:9
https://www.ebay.com/itm/164571981220
https://www.ebay.com/itm/164369108800
https://www.ebay.com/itm/264997898973

If you want to stick with the 4:3 -- https://www.ebay.com/itm/283504148116

I couldn't find any stellar deals on a MKIII or MKIV Navi. (i.e. a MKIV for $100 or < $60). I do have a spare MKIII that I can sell for $60 if you're interested.

The C23 will work with these components, but I would suggest grabbing a Siemens CID radio from an E8x and following Frankie's guide on shoe-horning that into the E38 (http://www.frankies-bmw.com/7series/...emens_prep.pdf)

Thanks!
-Ted

Yes my instrument cluster is operating perfectly, no issues at all. I do have a spare 16:9 screen from my old E39, I swapped the old 4:3 the other day and unfortunately still could not power up. My E38 is not equipped with navigation and only have an old analogue TV tuner, are you saying 16:9 won't work on my vehicle unless I've upgraded the Navi? I've left the TV tuner unplugged when I tested the C23 and the DSP amplifier with my old 16:9, would it cause an issue?

I am happy to stick with my old 4:3 as I'm not fussed with navigation (usually use my google map on my iphone nowadays), I just wanted to get my radio working again!

Thanks for the ebay links and your offer Ted, I'm from Melbourne Australia and will try to source a 4:3 replacement unit if you think this is the culprit.

[t3ddftw]

Yes my instrument cluster is operating perfectly, no issues at all. I do have a spare 16:9 screen from my old E39, I swapped the old 4:3 the other day and unfortunately still could not power up. My E38 is not equipped with navigation and only have an old analogue TV tuner, are you saying 16:9 won't work on my vehicle unless I've upgraded the Navi? I've left the TV tuner unplugged when I tested the C23 and the DSP amplifier with my old 16:9, would it cause an issue?

I am happy to stick with my old 4:3 as I'm not fussed with navigation (usually use my google map on my iphone nowadays), I just wanted to get my radio working again!

Thanks for the ebay links and your offer Ted, I'm from Melbourne Australia and will try to source a 4:3 replacement unit if you think this is the culprit.

Ah, well crap. There goes my hypothesis! The 16:9 and C23 should be able to operate just fine without the TV Tuner (These are called "Video Modules" by BMW) -- the only issue is that you'd get a rolling or stretched picture on the monitor from the VM.

I went back to my bench and tested keeping the I/K-Bus stuck "high" at 12v and experienced pretty much what you're seeing -- the monitor turned on for 60 seconds and then went off, the DSP was active and the radio was unresponsive. This is because keeping the bus high prevents the modules from speaking correctly.

Is there a remote chance that you have access to an oscilloscope? It would be great to visualize the status of the I/K-Bus.

I will dig through WDS in a few to figure out where the I/K-Bus junction is so you can start removing module by module to see if any restore life to the radio.

Thanks!
-Ted

[Technik333]

Ah, well crap. There goes my hypothesis! The 16:9 and C23 should be able to operate just fine without the TV Tuner (These are called "Video Modules" by BMW) -- the only issue is that you'd get a rolling or stretched picture on the monitor from the VM.

I went back to my bench and tested keeping the I/K-Bus stuck "high" at 12v and experienced pretty much what you're seeing -- the monitor turned on for 60 seconds and then went off, the DSP was active and the radio was unresponsive. This is because keeping the bus high prevents the modules from speaking correctly.

Is there a remote chance that you have access to an oscilloscope? It would be great to visualize the status of the I/K-Bus.

I will dig through WDS in a few to figure out where the I/K-Bus junction is so you can start removing module by module to see if any restore life to the radio.

Thanks!
-Ted

I didn't think the monitor was faulty as both of them couldn't get power through - the orange power light didn't lit up at all.

Unfortunately I don't have access to an oscilloscope to visual the status of the i-bus. Also worthwhile to note that my scan tool (C310) from the OBD port could not connect nor read the MID and the onboard monitor, however both the radio and DSP are working fine.

I suspect it is probably a short circuit somewhere, loose connection or a faulty module that are messing the i-bus signal. What module has the primary control of the i-bus signal? from the instrument cluster? Maybe I just need to plug and unplug it to reset it?

[t3ddftw]

In the E38, the LCM is the I-Bus master and the GM is the K-Bus master. I'm an E46 guy, where both are integrated, so I often forget about that. The IKE/KOMBI/Instument Cluster is in charge of bridging the I and K bus's traffic, so it's always a suspect.

I would look for the I-Bus and K-Bus junctions:
I-Bus: https://bmwteka.com/wds/en/e38new/5bf9bb9d

K-Bus: https://bmwteka.com/wds/en/e38new/6819d51c

Since the networks are star topology, you can unhook one item at a time until, hopefully, the radio comes back to life.

Thanks!
-Ted

[Technik333]

In the E38, the LCM is the I-Bus master and the GM is the K-Bus master. I'm an E46 guy, where both are integrated, so I often forget about that. The IKE/KOMBI/Instument Cluster is in charge of bridging the I and K bus's traffic, so it's always a suspect.

I would look for the I-Bus and K-Bus junctions:
I-Bus: https://bmwteka.com/wds/en/e38new/5bf9bb9d

K-Bus: https://bmwteka.com/wds/en/e38new/6819d51c

Since the networks are star topology, you can unhook one item at a time until, hopefully, the radio comes back to life.

Thanks!
-Ted

Ok just another update, I removed the 4:3 screen and tested it on another e38 and it works perfectly fine. Ok i'll try to locate the X596 and X939 connector, I suspect it is located under driver's side footwell instead of the glovebox given my E38 is a RHD. Should I be also checking the fuse block underneath the carpet and the LCM module as other has suggested?

[t3ddftw]

Ok just another update, I removed the 4:3 screen and tested it on another e38 and it works perfectly fine. Ok i'll try to locate the X596 and X939 connector, I suspect it is located under driver's side footwell instead of the glovebox given my E38 is a RHD. Should I be also checking the fuse block underneath the carpet and the LCM module as other has suggested?

According to the WDS, there's no difference in location for that terminal block between L/R Hand Drive. You can expect the I-Bus wires to be white with yellow dots or stripes.

Removing items from the K-Bus and I-Bus one by one will yield the same result as disconnecting the LCM.

I don't think it's worth digging out Fuse 106 (the terminal block under the carpet). It feeds power from the battery to a bunch of fuses (so it's upstream of the fusebox) as you can see here: https://bmwteka.com/wds/en/e38new/b80eaf88

I recommend ensuring there's 12v at the radio fuses (F46 & F69) to ensure there are no issues with Fuse Block 106.

-Ted

[Technik333]

According to the WDS, there's no difference in location for that terminal block between L/R Hand Drive. You can expect the I-Bus wires to be white with yellow dots or stripes.

Removing items from the K-Bus and I-Bus one by one will yield the same result as disconnecting the LCM.

I don't think it's worth digging out Fuse 106 (the terminal block under the carpet). It feeds power from the battery to a bunch of fuses (so it's upstream of the fusebox) as you can see here: https://bmwteka.com/wds/en/e38new/b80eaf88

I recommend ensuring there's 12v at the radio fuses (F46 & F69) to ensure there are no issues with Fuse Block 106.

-Ted

I found the i-bus junction and located the X596 and X939 plug underneath the glovebox, didn't have a chance to unplug them yet but I felt the carpet was a bit wet underneath - perhaps I've finally located the culprit!!! here is a photo of the connector strip.

https://imgur.com/WaWGTCC

[t3ddftw]

I found the i-bus junction and located the X596 and X939 plug underneath the glovebox, didn't have a chance to unplug them yet but I felt the carpet was a bit wet underneath - perhaps I've finally located the culprit!!! here is a photo of the connector strip.

https://imgur.com/WaWGTCC

Water is never good . Please let us know what you find!

-Ted

[Technik333]

Water is never good . Please let us know what you find!

-Ted

I took it out and gave it a clean - didn't see any sign of corrosion or anything but I will investigate this further. By the way I've came across this old thread:

https://www.bimmerforums.com/forum/s...o-power-at-all!

The author of this thread has a very similar issue except he didn't have the Navi 4:3 screen, he managed to fix it by sourcing another 12v+ (red/green wire) directly on both the MID and OBC and in my case it'll be the blue connector to the 4:3 screen. Apparently there is a TSB issued regarding damaged wires in the front right wheel well area which could cause electrical issue, here is the link:

http://www.e38.org/SI.Right.Front.Wh...ng.Harness.pdf

It is probably worthwhile to inspect it even though I'm getting 12v power to the radio unit but nothing to the Navi 4:3 screen.

[t3ddftw]

I took it out and gave it a clean - didn't see any sign of corrosion or anything but I will investigate this further. By the way I've came across this old thread:

https://www.bimmerforums.com/forum/s...o-power-at-all!

The author of this thread has a very similar issue except he didn't have the Navi 4:3 screen, he managed to fix it by sourcing another 12v+ (red/green wire) directly on both the MID and OBC and in my case it'll be the blue connector to the 4:3 screen. Apparently there is a TSB issued regarding damaged wires in the front right wheel well area which could cause electrical issue, here is the link:

http://www.e38.org/SI.Right.Front.Wh...ng.Harness.pdf

It is probably worthwhile to inspect it even though I'm getting 12v power to the radio unit but nothing to the Navi 4:3 screen.

An easy way to check this is to measure voltage at the red / green wire in the blue connector for the monitor.

[franco90]

did you check the fuse on the actual radio in the rear of the trunk I had the same issued on a E53 and the problem was solved when the radio unit on the trunk had a bad fuse
the radio is behind the amp check for water as well

[t3ddftw]

did you check the fuse on the actual radio in the rear of the trunk I had the same issued on a E53 and the problem was solved when the radio unit on the trunk had a bad fuse
the radio is behind the amp check for water as well

A good suggestion, but OP is not getting the OnBoard monitor to power on either.

-Ted