High Line System Dead - Help!

Dr Funk · 5th January 2013, 13:26

I was in my car about to drive off with the radio on when the system seemed to switch off. I could not switch it back on again. The backlight on the screen was on and there were signs of life from the autochanger, satnav and amps (quiet background speaker hiss). That was a couple of months ago and I have not had much luck since.

The units were dry, though the car had been damp due to the sunroof drain issue but this had soaked the carpets but not the spare wheel area. The battery had run flat and had just been charged in situ when this first happend.

I took the car to Huets (car audio specialists) who could not find the fault so they sent the units off to their repair company. The result was that the TV tuner was blamed but not repairable. I took the tuner home and had a poke around with a soldering iron although everything looked fine I wanted to eliminate dry joints on connectors etc.

They refitted the system and it all worked! Well for a few days until my battery went flat again (yes I'm going to change it!!). After charging the battery the system came on but after a few seconds the screen went blank with a white stripe at the bottom for a few seconds before going off completely. The radio was still working but the controls had frozen, and switching the ignition off and on again left me with a dead system again, just sat nav autochanger and amps showing signs of life and screen backlight.

I took out the TV tuner and did the soldering iron thing, no effect this time, also did the same as much as was possible with the head unit and Radio tuner also to no effect.

Next I bought a Hybrid TV tuner, as expected this did not work, but I don't think it is the TV tuner at fault.

I had found some discusion regarding the k-bus signal but having checked the wiring there seems to be no damaged connections as far as can be seen I have used contact cleaner / lubricant on all connectors. The only thing I could find was where the loom has been hacked into near the head unit but this was I assume for a nokia bluetooth unit and on inspection the connections are neat soldered and covered in self amalgamating tape.

At this point I suspect either the loom or the head unit, I would like to get a widescreen but best to find the problem before spending any more money.

Now I could really do with some help as I would like to verify if my hybrid tuner works and also the best way forward to get to the bottom of the issue. There is a BMW system on ebay which would give me a chance to swap out all the units at a price but ideally if there is someone in the Sussex area with a working highline system that would be prepared to have a swapping session I would be very grateful!

iandb1970 · 5th January 2013, 18:48

Reebs recommended this the procedure below and it worked for me:

Try this reset procedure for the high line ICE, it has worked on other units with the same problem that have been reported on here in the past. The procedure below came from the ICE/Electrical department of MG Rover Product Development.

ROVER 75 HIGH LINE ICE RADIO RESET PROCEDURE.

If the radio in this vehicle sticks on one station and you are unable to select anything other than tape or CD please carry out the following procedure to reset the unit.

1. Switch off unit using main on/off button (one with the orange triangle on the bottom right of the unit)

2. Switch on the unit using the same button

3. Within 8 seconds press and hold the TP button, on the unit, until the radio station read out re-appears and music etc can be heard

4. Switch off the unit again

5. Switch the unit back on and you can then select all radio bands along with CD, tape and tuner.

This should reset your Highline Radio.

Geoff130 · 5th January 2013, 21:05

Hi, I've just retrofitted a Hi-line system over the last month and having made my own wiring harness learnt some things the hard way. The sat nav and cd changer can be removed and the system will still work without them, see else where on this forum how to shut down the sat nav correctly. You can even disconnect the steering wheel interface and still use the monitor controls. At this point you should have the bord monitor, tv tuner and radio tuner. I found my system had to be turned off and back on with the ignition key before it came to life. The k-bus controls all these units and the tv tuner has a permanent battery feed to it and never turns off unless it gets a message to do so over the k-bus, turning on is also achieved the same way. All information about radio status and cd changer is sent over the k-bus and generated as a display in the tv tuner, it is then sent as three video signals to the bord monitor from the blue plug on the tv tuner. Removing this plug should give a plain white screen on your bord monitor, showing the cable to be ok. The k-bus line should be at battery voltage mostly with narrow negative pulses appearing during communication, if you have access to a scope you can check it while pressing buttons on the bord monitor, if you only have a DVM it should appear to be about 12v or higher. If it is low then you have a wiring fault on the k-bus. The k-bus is the white, red and yellow cable. I hope this helps, but to be honest I wish I could have swapped my units into a working system when I was doing mine.

Dr Funk · 5th January 2013, 22:43

Thanks for the replies,

The first suggestion of resetting the system is not an option unfortunately in my case as it will not switch on.

Geoff, hats off to you! Making your own wiring harness (and then installing it) sounds like a seriously vast job! I'll check the k-bus more closely, I have an old scope which may or may not decide to trigger, but at least I know what to look for. Also I can check for the white screen with the blue plug out, I guess a black screen would implicate the monitor as faulty.

Dr Funk · 8th January 2013, 23:20

Hi Geoff,

Could I pick your brains again, I have had a go at the following:

Removing the blue plug resulted in a black screen with no backlight
Looking at the Kbus on the radio module connector as this is where it's easily accessible shows it to be pulled low with power and ignition present. It's not a short but being pulled low by some electronics (0.38 - 0.4V)

This was the case with all units except the radio module connected and did not change when the other units (monitor tv tuner and satnav) were disconnected one by one.

Having built your own loom I guess you will have a good idea how the K-Bus is connected. I would have thought it connects all units such that with no units connected it would be floating and that each unit would have its own pull up resistor to 12V and an active pull down by the comms circuit in each unit capable of talking on it.

As I am seeing 0.38V on the K bus something is actively holding it down. With everything except the cd changer connected the only things to my mind that could be causing the problem are the cd changer assuming it's on the K-Bus, or the vehicle must have something connected to the K-bus, perhaps the comms for the steering wheel controls or trip computer which passes info to the monitor via the tv tuner presumably.

Does this line of thinking make sense? I can try disconnecting the CD changer next, and assuming there still is a pull down on the k-bus it must be the vehicle elecronics doing it. If this is the case do you (or anyone else??) have any further ideas?

Thanks in advance!

Geoff130 · 9th January 2013, 19:40

You would think this was the case but there are only two pull up resistors on the whole bus, one in the Instrument pack and another in the Body Control Unit, you can simulate it with a 10k from the k-bus line to battery +ve but one above sends the messages that key is in aux, ign or off. It looks as if your Hi Line bus isn't connected to the rest of the car. There should be a header inside the centre console where the k-bus, Aux power, illumination, and permanent power are distributed. It is about 50mm long, 10mm wide and 20mm deep, usually wrapped in foam tape. You can do a continuity check from here to your units and you will also find the k-bus on the instrument pack and the main light switch. I found on the bench without a pull up on the k-bus the on/off switch of the monitor did nothing, with a pull up, it would illuminate the triangular led next to it and I could now view button press messages. It was only when I put it in the car with the IPK and body control unit connected it turned on properly. What may be more useful to you is that with only power to the monitor and nothing else the screen was blank white as soon as the aux power was turned on. It would go dark ( but still blank) as soon as it was connected to the TV tuner or Nav ECU. I hope this helps, Geoff

Dr Funk · 10th January 2013, 16:10

Hi Geoff,

Thank you, that is again very informative! I had a look for the header but instead found a box mounted behind the monitor sitting in a bracket on a foam bed which at first I thought was it, it's a Lear "Boardmonitor remote switch interface module" and is connected to the loom via a 6 pin connector and includes the k-bus. I noticed that with each unit I remove the kbus voltage rises a few tens to around 100 millivolts and is now at around 0.7V with this interface removed, having started at 0.38V with most of the units connected suggesting a relatively high impedance, half ***** pull down by the offending article, and a k-bus to ground impedance by the Highline units.
Having now disconnected everything including this remote switch interface the only things left if I've understood right are the body control unit and the instrument pack.
I'm confident the HiLine bus (k-bus) is connected as I see a specific voltage on it, so it's not floating, also it was working, stopped then worked again before stopping again permanently some weeks back.
If this kbus connects to the instrument pack and body control unit, then these are the only two remaining connections to the kbus so one of these has to be pulling it low.

Another thought is that this must be a seperate bus to that controlling other functions as everything else in the car still works (I understand other functions also use a serial bus). I have just fitted a new battery and noticed that the information panel on the instrument pack is showing a couple of lines of dead pixels for the first time, I'm just wondering if the effects of the damp when I had the sunroof drain and flooded scuttle/plenum area may have affected the instrument pack and that this may be the cause of the bus pulldown? It is otherwise functioning, I am clutching at straws!

In conclusion, as the bus is still low (0.7V) with no Highline units fitted I'm assuming this has to be a symtom of the problem which is with the car somewhere. in the absence of anything else the instrument pack would seem the most likely candidate but only if this bus is highline only (as all other functions are correct). I am assuming that the k-bus should be sitting at 12V under normal quiescent conditions.

Is there an easy way to disconnect the highline loom (k-bus line in particular) from the instrument pack? or failing that the body control unit? If I could isolate these units I might see which is pulling down (probably not that simple though!)

Anyway any further ideas most welcome! Thanks

Geoff130 · 10th January 2013, 19:43

I may have given you the wrong impression of the size of the k-bus, it depends on the amount of goodies you have, as well as the interface to the steering wheel controls it also goes to the rain sensor, parking aid ecu, sunroof ecu, seat memory ecu and Immobilisation ecu, and even if you don't have things fitted, some models have the wiring in place anyway. Basically if it's ancillary then it goes on the k-bus, transmission control goes on the Can-bus as you need the extra speed, that includes things like ABS ecu, Engine ecu and auto gearbox ecu and the instrument pack. If you can start your car then at least there is some of the k-bus working correctly. The sunroof ecu is behind the front interior lamp and looks like it's part of the sunroof motor-gearbox from the picture of that I've seen, perhaps if the roof flooded that is where you could take a look. To split the k-bus if you find the header I mentioned (I think it is down the left side behind the ashtray module, I can't remember exactly what mine was like before I pulled it apart the first time! ) you can take the shorting link section off the bottom and remove individual connections but you need to be careful as I wouldn't advise upsetting the immobiliser ecu.

Dr Funk · 10th January 2013, 23:37

Thanks Geoff,

That changes things in my mind again, basically the functions you mentioned all work, (I have the SE version like you) so it's back to the highline part of the loom. Just now I have been trying to get to the instrument pack but having removed the cowl and screws am unable to pull it out, feels like it's secured from behind so gave up. I then got to the body control unit and got two of the three connectors off and then had a look at the voltage on the k-bus (always on the connector for the radio), which was around 0.74V.

From what you say the k-bus itself must be working hence what you said before about the highline part of the k-bus having come adrift. I am still puzzled by the fact that is is not completely floating as it would be if it were simply disconnected but perhaps a damp corroded connector is a possibility? As you say I need to get to the header and can then check from there. I would also like to check the kbus where I know it is working and is easy to access ideally on a large connector (such as the radio module connector)

I see what you mean regarding possible damp at the sunroof ECU, I won't start there though as the sunroof works and there is no sign of any damp around this area, it all seemed to be around the footwells and carpets.

Anyway, thanks again and I'll let you know what I find - assuming I can get the heater controls and the other stuff out to get to it!

Geoff130 · 11th January 2013, 20:41

After you took out the IPK cowl did you find the screw at the top centre of the pack? With you having the sunroof the K-bus will be on the large connector at the base of the drivers A pillar, easy enough if you haven't got an airbag in it. Pull away the door seal up the pillar and pull the trim away from the top then pull it upwards and back from the dash.

5th January 2013, 13:26	#1
Dr Funk Newbie MG ZT-T 190SE, Truimph Sprint ST 1050 Join Date: Apr 2012 Location: Brighton Posts: 15 Thanks: 0 Thanked 0 Times in 0 Posts	High Line System Dead - Help! I was in my car about to drive off with the radio on when the system seemed to switch off. I could not switch it back on again. The backlight on the screen was on and there were signs of life from the autochanger, satnav and amps (quiet background speaker hiss). That was a couple of months ago and I have not had much luck since. The units were dry, though the car had been damp due to the sunroof drain issue but this had soaked the carpets but not the spare wheel area. The battery had run flat and had just been charged in situ when this first happend. I took the car to Huets (car audio specialists) who could not find the fault so they sent the units off to their repair company. The result was that the TV tuner was blamed but not repairable. I took the tuner home and had a poke around with a soldering iron although everything looked fine I wanted to eliminate dry joints on connectors etc. They refitted the system and it all worked! Well for a few days until my battery went flat again (yes I'm going to change it!!). After charging the battery the system came on but after a few seconds the screen went blank with a white stripe at the bottom for a few seconds before going off completely. The radio was still working but the controls had frozen, and switching the ignition off and on again left me with a dead system again, just sat nav autochanger and amps showing signs of life and screen backlight. I took out the TV tuner and did the soldering iron thing, no effect this time, also did the same as much as was possible with the head unit and Radio tuner also to no effect. Next I bought a Hybrid TV tuner, as expected this did not work, but I don't think it is the TV tuner at fault. I had found some discusion regarding the k-bus signal but having checked the wiring there seems to be no damaged connections as far as can be seen I have used contact cleaner / lubricant on all connectors. The only thing I could find was where the loom has been hacked into near the head unit but this was I assume for a nokia bluetooth unit and on inspection the connections are neat soldered and covered in self amalgamating tape. At this point I suspect either the loom or the head unit, I would like to get a widescreen but best to find the problem before spending any more money. Now I could really do with some help as I would like to verify if my hybrid tuner works and also the best way forward to get to the bottom of the issue. There is a BMW system on ebay which would give me a chance to swap out all the units at a price but ideally if there is someone in the Sussex area with a working highline system that would be prepared to have a swapping session I would be very grateful!

5th January 2013, 18:48	#2
iandb1970 Avid contributor Rover 75 Connoisseur SE Tourer 2.5 V6 Auto Hi-Line Join Date: Dec 2012 Location: Highclere Posts: 233 Thanks: 30 Thanked 10 Times in 9 Posts	Reebs recommended this the procedure below and it worked for me: Try this reset procedure for the high line ICE, it has worked on other units with the same problem that have been reported on here in the past. The procedure below came from the ICE/Electrical department of MG Rover Product Development. ROVER 75 HIGH LINE ICE RADIO RESET PROCEDURE. If the radio in this vehicle sticks on one station and you are unable to select anything other than tape or CD please carry out the following procedure to reset the unit. 1. Switch off unit using main on/off button (one with the orange triangle on the bottom right of the unit) 2. Switch on the unit using the same button 3. Within 8 seconds press and hold the TP button, on the unit, until the radio station read out re-appears and music etc can be heard 4. Switch off the unit again 5. Switch the unit back on and you can then select all radio bands along with CD, tape and tuner. This should reset your Highline Radio.

5th January 2013, 21:05	#3
Geoff130 Loves to post MG ZT 190, Rover 75 CDTi, Honda VFR 750, Honda CB550F Join Date: Aug 2010 Location: Derby Posts: 393 Thanks: 75 Thanked 36 Times in 28 Posts	Hi, I've just retrofitted a Hi-line system over the last month and having made my own wiring harness learnt some things the hard way. The sat nav and cd changer can be removed and the system will still work without them, see else where on this forum how to shut down the sat nav correctly. You can even disconnect the steering wheel interface and still use the monitor controls. At this point you should have the bord monitor, tv tuner and radio tuner. I found my system had to be turned off and back on with the ignition key before it came to life. The k-bus controls all these units and the tv tuner has a permanent battery feed to it and never turns off unless it gets a message to do so over the k-bus, turning on is also achieved the same way. All information about radio status and cd changer is sent over the k-bus and generated as a display in the tv tuner, it is then sent as three video signals to the bord monitor from the blue plug on the tv tuner. Removing this plug should give a plain white screen on your bord monitor, showing the cable to be ok. The k-bus line should be at battery voltage mostly with narrow negative pulses appearing during communication, if you have access to a scope you can check it while pressing buttons on the bord monitor, if you only have a DVM it should appear to be about 12v or higher. If it is low then you have a wiring fault on the k-bus. The k-bus is the white, red and yellow cable. I hope this helps, but to be honest I wish I could have swapped my units into a working system when I was doing mine.

5th January 2013, 22:43	#4
Dr Funk Newbie MG ZT-T 190SE, Truimph Sprint ST 1050 Join Date: Apr 2012 Location: Brighton Posts: 15 Thanks: 0 Thanked 0 Times in 0 Posts	Thanks for the replies, The first suggestion of resetting the system is not an option unfortunately in my case as it will not switch on. Geoff, hats off to you! Making your own wiring harness (and then installing it) sounds like a seriously vast job! I'll check the k-bus more closely, I have an old scope which may or may not decide to trigger, but at least I know what to look for. Also I can check for the white screen with the blue plug out, I guess a black screen would implicate the monitor as faulty.

8th January 2013, 23:20	#5
Dr Funk Newbie MG ZT-T 190SE, Truimph Sprint ST 1050 Join Date: Apr 2012 Location: Brighton Posts: 15 Thanks: 0 Thanked 0 Times in 0 Posts	Hi Geoff, Could I pick your brains again, I have had a go at the following: Removing the blue plug resulted in a black screen with no backlight Looking at the Kbus on the radio module connector as this is where it's easily accessible shows it to be pulled low with power and ignition present. It's not a short but being pulled low by some electronics (0.38 - 0.4V) This was the case with all units except the radio module connected and did not change when the other units (monitor tv tuner and satnav) were disconnected one by one. Having built your own loom I guess you will have a good idea how the K-Bus is connected. I would have thought it connects all units such that with no units connected it would be floating and that each unit would have its own pull up resistor to 12V and an active pull down by the comms circuit in each unit capable of talking on it. As I am seeing 0.38V on the K bus something is actively holding it down. With everything except the cd changer connected the only things to my mind that could be causing the problem are the cd changer assuming it's on the K-Bus, or the vehicle must have something connected to the K-bus, perhaps the comms for the steering wheel controls or trip computer which passes info to the monitor via the tv tuner presumably. Does this line of thinking make sense? I can try disconnecting the CD changer next, and assuming there still is a pull down on the k-bus it must be the vehicle elecronics doing it. If this is the case do you (or anyone else??) have any further ideas? Thanks in advance!

9th January 2013, 19:40	#6
Geoff130 Loves to post MG ZT 190, Rover 75 CDTi, Honda VFR 750, Honda CB550F Join Date: Aug 2010 Location: Derby Posts: 393 Thanks: 75 Thanked 36 Times in 28 Posts	You would think this was the case but there are only two pull up resistors on the whole bus, one in the Instrument pack and another in the Body Control Unit, you can simulate it with a 10k from the k-bus line to battery +ve but one above sends the messages that key is in aux, ign or off. It looks as if your Hi Line bus isn't connected to the rest of the car. There should be a header inside the centre console where the k-bus, Aux power, illumination, and permanent power are distributed. It is about 50mm long, 10mm wide and 20mm deep, usually wrapped in foam tape. You can do a continuity check from here to your units and you will also find the k-bus on the instrument pack and the main light switch. I found on the bench without a pull up on the k-bus the on/off switch of the monitor did nothing, with a pull up, it would illuminate the triangular led next to it and I could now view button press messages. It was only when I put it in the car with the IPK and body control unit connected it turned on properly. What may be more useful to you is that with only power to the monitor and nothing else the screen was blank white as soon as the aux power was turned on. It would go dark ( but still blank) as soon as it was connected to the TV tuner or Nav ECU. I hope this helps, Geoff

10th January 2013, 16:10	#7
Dr Funk Newbie MG ZT-T 190SE, Truimph Sprint ST 1050 Join Date: Apr 2012 Location: Brighton Posts: 15 Thanks: 0 Thanked 0 Times in 0 Posts	Hi Geoff, Thank you, that is again very informative! I had a look for the header but instead found a box mounted behind the monitor sitting in a bracket on a foam bed which at first I thought was it, it's a Lear "Boardmonitor remote switch interface module" and is connected to the loom via a 6 pin connector and includes the k-bus. I noticed that with each unit I remove the kbus voltage rises a few tens to around 100 millivolts and is now at around 0.7V with this interface removed, having started at 0.38V with most of the units connected suggesting a relatively high impedance, half ***** pull down by the offending article, and a k-bus to ground impedance by the Highline units. Having now disconnected everything including this remote switch interface the only things left if I've understood right are the body control unit and the instrument pack. I'm confident the HiLine bus (k-bus) is connected as I see a specific voltage on it, so it's not floating, also it was working, stopped then worked again before stopping again permanently some weeks back. If this kbus connects to the instrument pack and body control unit, then these are the only two remaining connections to the kbus so one of these has to be pulling it low. Another thought is that this must be a seperate bus to that controlling other functions as everything else in the car still works (I understand other functions also use a serial bus). I have just fitted a new battery and noticed that the information panel on the instrument pack is showing a couple of lines of dead pixels for the first time, I'm just wondering if the effects of the damp when I had the sunroof drain and flooded scuttle/plenum area may have affected the instrument pack and that this may be the cause of the bus pulldown? It is otherwise functioning, I am clutching at straws! In conclusion, as the bus is still low (0.7V) with no Highline units fitted I'm assuming this has to be a symtom of the problem which is with the car somewhere. in the absence of anything else the instrument pack would seem the most likely candidate but only if this bus is highline only (as all other functions are correct). I am assuming that the k-bus should be sitting at 12V under normal quiescent conditions. Is there an easy way to disconnect the highline loom (k-bus line in particular) from the instrument pack? or failing that the body control unit? If I could isolate these units I might see which is pulling down (probably not that simple though!) Anyway any further ideas most welcome! Thanks

10th January 2013, 19:43	#8
Geoff130 Loves to post MG ZT 190, Rover 75 CDTi, Honda VFR 750, Honda CB550F Join Date: Aug 2010 Location: Derby Posts: 393 Thanks: 75 Thanked 36 Times in 28 Posts	I may have given you the wrong impression of the size of the k-bus, it depends on the amount of goodies you have, as well as the interface to the steering wheel controls it also goes to the rain sensor, parking aid ecu, sunroof ecu, seat memory ecu and Immobilisation ecu, and even if you don't have things fitted, some models have the wiring in place anyway. Basically if it's ancillary then it goes on the k-bus, transmission control goes on the Can-bus as you need the extra speed, that includes things like ABS ecu, Engine ecu and auto gearbox ecu and the instrument pack. If you can start your car then at least there is some of the k-bus working correctly. The sunroof ecu is behind the front interior lamp and looks like it's part of the sunroof motor-gearbox from the picture of that I've seen, perhaps if the roof flooded that is where you could take a look. To split the k-bus if you find the header I mentioned (I think it is down the left side behind the ashtray module, I can't remember exactly what mine was like before I pulled it apart the first time! ) you can take the shorting link section off the bottom and remove individual connections but you need to be careful as I wouldn't advise upsetting the immobiliser ecu.

10th January 2013, 23:37	#9
Dr Funk Newbie MG ZT-T 190SE, Truimph Sprint ST 1050 Join Date: Apr 2012 Location: Brighton Posts: 15 Thanks: 0 Thanked 0 Times in 0 Posts	Thanks Geoff, That changes things in my mind again, basically the functions you mentioned all work, (I have the SE version like you) so it's back to the highline part of the loom. Just now I have been trying to get to the instrument pack but having removed the cowl and screws am unable to pull it out, feels like it's secured from behind so gave up. I then got to the body control unit and got two of the three connectors off and then had a look at the voltage on the k-bus (always on the connector for the radio), which was around 0.74V. From what you say the k-bus itself must be working hence what you said before about the highline part of the k-bus having come adrift. I am still puzzled by the fact that is is not completely floating as it would be if it were simply disconnected but perhaps a damp corroded connector is a possibility? As you say I need to get to the header and can then check from there. I would also like to check the kbus where I know it is working and is easy to access ideally on a large connector (such as the radio module connector) I see what you mean regarding possible damp at the sunroof ECU, I won't start there though as the sunroof works and there is no sign of any damp around this area, it all seemed to be around the footwells and carpets. Anyway, thanks again and I'll let you know what I find - assuming I can get the heater controls and the other stuff out to get to it!

11th January 2013, 20:41	#10
Geoff130 Loves to post MG ZT 190, Rover 75 CDTi, Honda VFR 750, Honda CB550F Join Date: Aug 2010 Location: Derby Posts: 393 Thanks: 75 Thanked 36 Times in 28 Posts	After you took out the IPK cowl did you find the screw at the top centre of the pack? With you having the sunroof the K-bus will be on the large connector at the base of the drivers A pillar, easy enough if you haven't got an airbag in it. Pull away the door seal up the pillar and pull the trim away from the top then pull it upwards and back from the dash.