CAN BUS errors on BMW E60, advise needed

alila · Post by **alila** » Tue Mar 12, 2019 6:23 pm

Hi,

I just bought the Picoscope Automotive version and I am learning to use it. My challenge is with BMW 520d 2007 that has random DTC, Airbag, Transmission Fail, ABS and random other errors.

DTC unit is replaced and errors continue. I bought the Picoscope and builded math channel with alarms to notify on CAN BUS errors with this guide: viewtopic.php?t=12871

Friend of mine has BMW 520i 2003 without any errors in memory and I did the math channel test to alarm on errors. Waited for 5 minutes and got 4 errors in that time. After that I did the same with my own BMW 520d that has constant errors and got over 50 errors in 5 minutes.

Reading the error memory with BMW software it indicates the following:
- DDE: Zero Quantity adaptation, injector, cylinder 1
- PT-CAN communications error

Next I started to unplug modules in the CAN BUS to see if I can get the error level down. After many different modules I disconnected the main DDE unit and right after that errors in CAN BUS ended.

Any comments and advice since I am new with this Picoscope device.
Am I proceeding to the right direction?
Can you see from the captured data what could be the issue?
Should I start planning to replace DDE unit or could it be device behind the DDE that is the root issue?

Attached is the capture from working BMW 520i and the BMW 520d one having all the issues. Also more info on the DDE can be found here: https://www.newtis.info/tisv2/a/en/e60- ... s/HRMA4xAD

Thanks,
Antti

alila · Post by **alila** » Thu Mar 14, 2019 7:16 pm

Did some additional testing. Tested again with math channel and alert from mask fails. Car was on warm garage for 2 days. I got 50 mask fails in 5 minutes. Took out the DDE unit to a freezer (-18C) for 8 hours. After that tested again and got 170 mask fails in 5 minutes. Could it be a cold solder joint inside the DDE unit?

alila · Post by **alila** » Mon Mar 25, 2019 5:33 pm

Still troubleshooting the same issue. Now I replaced the ECU (DDE) unit with used one. Faults still continue. I did a capture on the error. There is a strange spike in the end of packet coming form ID A8 which should be the ECU unit according to BMW documentation. Has anyone come across these kind of spikes in BMW?

This case study had exactly the same kind of spike but my Pico has only 2 channels so I cannot do the same kind of test with two points at the same time
https://www.picoauto.com/library/case-s ... ions-fault

Here is a picture attached

liviu2004 · Post by **liviu2004** » Mon Mar 25, 2019 9:14 pm

Spike is normal. Move on to other areas.

Post by **ben.martins** » Thu Mar 28, 2019 4:12 pm

Hello Alila,

I think our recent videos on CAN decoding may help point you in the right direction. The following link is for a new guided test we will be releasing soon https://youtu.be/Bc2R462dlac.

This next link takes you to our Practical Pico session where Barney and Steve walk you through connection and decoding. https://youtu.be/Bc2R462dlac

There are some additional techniques that will help you better understand the network and what faults are potentially present. I think we need to more time on the screen to allow for the errors to stay with in the buffers. I have a feeling that some of the errors are no longer present as they have left the screen. As per the first video a setting of 200ms/div and increasing your sample rate to 10Ms will give you enough detail to decode and spot a fault. The only problem is you may not be able to upload to the forum as the file size will be rather big!

I would be focusing on the fault codes you have. Some questions I would be asking is why only cylinder 1 for adaption settings? If there was an ECU fault would we not expect to see more than just one? I don't know the answer just curious. The other thing is the fault code for the PT-CAN. Is there a specific code or is this it? I would have expected to see Lost Comms with Gearbox or Lost Comms with DDE? It might be there is more guidence in this than we think.

I hope this helps and do please let us know how you get on.

Kind regards

Ben

alila · Post by **alila** » Tue Apr 02, 2019 4:20 pm

I did more testing and now driving with oscilloscope I was able to find much bigger issues. Also on the second test the car light up all possible warning lights and I was able to capture that in the oscilloscope. I wrote more details with screenshots from the testing. Also error codes in the end. PDF file attached.

There are many communication fails on the bus recorded in different ECU units.

Thanks,
Antti

liviu2004 · Post by **liviu2004** » Tue Apr 02, 2019 8:07 pm

So you have an short to plus in the tcm can lines.

alila · Post by **alila** » Wed Apr 03, 2019 7:42 pm

Today I looked at the connector that is attached to transmission case. It was moist on transmission oil. Leakage is not that big as it would drip oil outside of transmission case. Only moist in the connector. Possibly the seal gasget is leaking transmission oil into the connector. Could that small amount of oil cause short inside the connector?

jung cheol an · Post by **jung cheol an** » Thu Apr 04, 2019 3:30 am

Hi friend
As far as I'm concerned, if the ground wire in the transmission computer
It is estimated that power line and can line short circuit
As with the question, it is possible to cause problems by moisture.
Remove the moisture from the connector and run the test
If the same symptom occurs, check the transmission computer or internal wiring

Set the measurement time to 200 ms / sampling rate 5 M or more when measuring with pico
Please measure again.

alila · Post by **alila** » Wed May 08, 2019 1:56 pm

Hi,

Finally I replaced the TCM unit from transmission mechatronics and everything is solved. No more errors and no more spikes in the can bus. Wiring was all OK and the TCM module was broken.

Thanks for all your replys!
Antti

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