2004 VW Polo 9N Electrical Issue

[emile777]

Hi guys, as the subject suggests I’m having an electrical issue with my polo. Please view these 2 youtube links to see what it’s doing

https://youtu.be/z5HVLAINJCE
https://youtu.be/5lhKKVlsHfE

I checked the following:

*All fuses imcluding the link fuses on top op battery
*Battery terminals
*Negative leads on body
*Ran through the cabling from the ecu towards accessible components quickly didn’t see any broken wires.

Vagcom throws faults everywhere dont have codes with me right now.

It started with the powersteering failing intermittently and then coming on as soon as I come to a stop. Now just permantly no powersteering and christmas lights on my cluster, impossible to start the car when this is happening. Please anyone have an idea where I could find the problem to this?

[VGTI]

Replace tha battery and feedback...

[emile777]

I’ll see if I can borrow a good battery to check if it works, this battery is readin 12.3v with the multimeter

[VGTI]

I once had something similar, everything would go dead and come back on. It was the battery that was busy failing.

I have also heard that funny stuff can happen when the tail light bulbs are not making proper connection... so at a far push check that out as well.

[emile777]

Tail lights are working fine but will give them a good clean anyway will update asap

[emile777]

Tail lights perfect, checked a new varta battery it’s doing the same thing.

[uncivilized]

If the clusta is a problem I suggest checking the control box situated under the dash. I had endless problems with my flashers because of it and learnt that it controls the cluster and wipers as well

Sent from my HUAWEI VNS-L31 using Tapatalk

[emile777]

Not really a cluster problem I believe, but will give it a bash anyway thanks.

[panic-mechanic]

What would be helpfull is those fault codes. If any of them says failure to communicate to the body control module then yes.

[emile777]

Thanks Panic, my vag com is at a friends house will post results tomorrow, I dont recall a failure to communicate to the body control module, but will check it out and post results

[emile777]

Pulled the control panel under the dash, nothing out of the ordinary, will update with fault codes asap

[uncivilized]

Does your car have 2 large fuses next to the battery? If it does just clean them up and put them back.

Sent from my HUAWEI VNS-L31 using Tapatalk

[emile777]

No fuses next to the battery

[emile777]

Alright brace yourselves...

01 Engine:
18056-P1648 Data bus powertrain faulty
18090- P1682 Data bus powertrain faulty: implausible message from ABS controller
17978-P1570 Engine Control Module disabled
18045-P1637 Data bus powertrain: missing message from central electronic control
16885-P0501 Vehicle speed sensor A: range/performance
16891-P0507 idle air control system: RPM higher than expected
18043-P1635 data bus powertrain: missing message from AC control
18010-P1602 Power supply B+ terminal 30: low voltage
18104 data bus powertrain:implausible message from steering colum controller

09 Central Control:
01321 control unit for airbag j234
01316 brake control unit
01317 control unit in dash panel insert j285
01314 ECU
01312 Data bus drive
01336 VW Group convenience data bus
01309 Steering assistance control unit J500

17 Instruments:
01312
01314
01316
01321
1322 multi function unit control unit J501

03 ABS
01312 DBS
01314 ECU

HVAC:

65535-U48023 internal control module memory checksum error
01271 motor for temperature flap v68
01299 diagnostic interface for data bus j533
01317 J285

15 Airbags:
01312
01317

46 Central Comfort:
01336 & 01332 door control unit J386

After clearing all codes and starting again symptoms continue with everything going crazy.

Fault codes after clearing and starting:

01 Engine:
18056
18090
18104

09 Central Control:

01312
01336
01309

So...can I set the car on fire now?

[emile777]

Anyone...

[panic-mechanic]

many of those faults are low voltage or bad earth related. Start really looking at contacts, earths, fuses or the body control unit.

[emile777]

many of those faults are low voltage or bad earth related. Start really looking at contacts, earths, fuses or the body control unit.

Thanks Panic, will try and take a look again.

[emile777]

many of those faults are low voltage or bad earth related. Start really looking at contacts, earths, fuses or the body control unit.

I literally pulled every single fuse, every relay, all the earth leads the car has, cleaned and inspected them and still nothing. Pulled the ECU checked all the connections and wiring and still nothing. Still getting the data bus powertrain faulty code and car going crazy. Takes me 10-15min to get lucky and get the car started. One thing I forgot to mention and have noticed now again. When the weather is cool it acts like this. Yesterday I left the car baking in the sun, moment I switched on the ignition it started straight away with powersteering working and everything as should be. Almost like a connection crimping when it’s cold and when it’s hot it’s making good connection. I honestly don’t know anymore

[uncivilized]

If you know of anyone with the same car as yours try the control box. I don't know why but too me it seems that's the problem. It may seem fine but once moisture gets into it,it can cause migraines.

Sent from my HUAWEI VNS-L31 using Tapatalk

[emile777]

If you know of anyone with the same car as yours try the control box. I don't know why but too me it seems that's the problem. It may seem fine but once moisture gets into it,it can cause migraines.

Sent from my HUAWEI VNS-L31 using Tapatalk

Don’t really know anyone with the same car funny enough I took a blow dryer and heated up the BCM thinking maybe if it’s got something to do with the heat but still didnt do nothing haha

[uncivilized]

Try unplugging the box and start the car

Sent from my HUAWEI VNS-L31 using Tapatalk

[emile777]

Try unplugging the box and start the car

Sent from my HUAWEI VNS-L31 using Tapatalk

Will try that in the morning thanks

[emile777]

Pulled the BCM just now and the car started first try, but it’s still doing this:

https://youtu.be/xpZMy2msSBc

[uncivilized]

Can u upload a pic of the box because when you pull that out nothing's supposed to work on the cluster

Sent from my HUAWEI VNS-L31 using Tapatalk

[emile777]

This is the culprit not causing the start

https://ibb.co/jygfJYM

This is the complete BCM

https://ibb.co/VwTxFM3