K Bus issues

MGMarc · 30th October 2015, 07:17

Through my own ineptitude I have started a new thread relating to my K Bus issues as it was getting muddled and becoming unclear to even myself

Quick recap on the symptoms which can work and fail sporadically

* No indicator or headlight tell tale on the dash (never worked)
* Climate control shows Er where temp should be
* Boot won't open
* Car won't lock from fob (unlocks fine)
* Rear demister not working

Tasks which I have already carried out

1) Removed radio cassette and climate control which made no difference

2) Found connector/header C0289 and all of the K Bus wires have 12.51v (white wire with a red line and yellow trace)

3) Checked voltage on the K Bus wire in the engine bay at the FBH 12.51v

4) Checked the voltage on the K Bus wire (pink wire) at the climate control 12.51v

5) Checked the voltage on the K Bus wire at the CD changer (no CD changer) K Bus wire 12.51v

Picture of C0289 which is located in the driver kick panel

I have ordered a full wiring diagram but wondering what the next step would be to try and remedy the issue?

Phil-T4 · 30th October 2015, 07:36

ok you have a good volts on the K-bus but it is never a static voltage, depending on the sampling rate of your meter you should see this fluctuating to indicate communications are taking place.

MGMarc · 30th October 2015, 07:40

It's a cheap draper digital multimeter which shows no fluctuations at all, I've tried a more expensive fluke meter and that shows static voltage too

Can I confirm I have the right wire for the K Bus, White with a red line and yellow trace

Phil-T4 · 30th October 2015, 07:44

That is your problem then, something is holding the bus high all the time, you will have to disconnect each unit until you see comms, a scope on the line may be better but even the cheap meter should show some fluctuation.

Phil-T4 · 30th October 2015, 07:48

Quote:

Originally Posted by MGMarc

It's a cheap draper digital multimeter which shows no fluctuations at all, I've tried a more expensive fluke meter and that shows static voltage too

Can I confirm I have the right wire for the K Bus, White with a red line and yellow trace

Yes that is correct, if you have rear parking sensors, disconnect that ecu.

MGMarc · 30th October 2015, 07:51

Will persevere again tonight and hopefully get a result

I will start with the BCU and LSM wires then add others one at a time

👍

(she's quite a basic spec alas no parking sensors)

Phil-T4 · 30th October 2015, 08:01

Quote:

Originally Posted by MGMarc

Will persevere again tonight and hopefully get a result

I will start with the BCU and LSM wires then add others one at a time

👍

(she's quite a basic spec alas no parking sensors)

Both these units have pull up resistors, and on a working system if you disconnect both, then the voltage will drop to zero.

Good luck!

SD1too · 30th October 2015, 08:25

Quote:

Originally Posted by MGMarc

* No indicator or headlight tell tale on the dash (never worked)

Marc,

You're in excellent hands with Phil-T4 but I couldn't help noticing the above important symptom. Here's an extract from RAVE:
"If the main beam indicator lamp and the direction indicator tell-tale lamps operate, this is an indication that the K-bus link to the IPK is functioning correctly."

How about that?

The K-bus connection to the IPK (instrument pack) is on pin 3 of the white 18 pin connector C0230.

Simon

MGMarc · 30th October 2015, 08:38

Does it say where connector C0230 is located?

marinabrian · 30th October 2015, 08:56

Quote:

Originally Posted by MGMarc

Does it say where connector C0230 is located?

It is the white connector to the rear of the instrument pack

Brian

30th October 2015, 07:17	#1
MGMarc Avid contributor MG ZT-T Join Date: Oct 2015 Location: Dorset Posts: 135 Thanks: 6 Thanked 23 Times in 11 Posts	K Bus issues Through my own ineptitude I have started a new thread relating to my K Bus issues as it was getting muddled and becoming unclear to even myself Quick recap on the symptoms which can work and fail sporadically * No indicator or headlight tell tale on the dash (never worked) * Climate control shows Er where temp should be * Boot won't open * Car won't lock from fob (unlocks fine) * Rear demister not working Tasks which I have already carried out 1) Removed radio cassette and climate control which made no difference 2) Found connector/header C0289 and all of the K Bus wires have 12.51v (white wire with a red line and yellow trace) 3) Checked voltage on the K Bus wire in the engine bay at the FBH 12.51v 4) Checked the voltage on the K Bus wire (pink wire) at the climate control 12.51v 5) Checked the voltage on the K Bus wire at the CD changer (no CD changer) K Bus wire 12.51v Picture of C0289 which is located in the driver kick panel I have ordered a full wiring diagram but wondering what the next step would be to try and remedy the issue? Last edited by MGMarc; 30th October 2015 at 07:23..

30th October 2015, 07:40	#3
MGMarc Avid contributor MG ZT-T Join Date: Oct 2015 Location: Dorset Posts: 135 Thanks: 6 Thanked 23 Times in 11 Posts	It's a cheap draper digital multimeter which shows no fluctuations at all, I've tried a more expensive fluke meter and that shows static voltage too Can I confirm I have the right wire for the K Bus, White with a red line and yellow trace Last edited by MGMarc; 30th October 2015 at 07:44..

30th October 2015, 07:36	#2
Phil-T4 I really should get out more....... MG ZT-T, Rover 75 Tourer Join Date: Mar 2011 Location: Olney Posts: 2,969 Thanks: 245 Thanked 1,088 Times in 657 Posts	ok you have a good volts on the K-bus but it is never a static voltage, depending on the sampling rate of your meter you should see this fluctuating to indicate communications are taking place.

30th October 2015, 07:44	#4
Phil-T4 I really should get out more....... MG ZT-T, Rover 75 Tourer Join Date: Mar 2011 Location: Olney Posts: 2,969 Thanks: 245 Thanked 1,088 Times in 657 Posts	That is your problem then, something is holding the bus high all the time, you will have to disconnect each unit until you see comms, a scope on the line may be better but even the cheap meter should show some fluctuation.

30th October 2015, 07:51	#6
MGMarc Avid contributor MG ZT-T Join Date: Oct 2015 Location: Dorset Posts: 135 Thanks: 6 Thanked 23 Times in 11 Posts	Will persevere again tonight and hopefully get a result I will start with the BCU and LSM wires then add others one at a time 👍 (she's quite a basic spec alas no parking sensors)

30th October 2015, 08:38	#9
MGMarc Avid contributor MG ZT-T Join Date: Oct 2015 Location: Dorset Posts: 135 Thanks: 6 Thanked 23 Times in 11 Posts	Does it say where connector C0230 is located?