ABS Trifecta - troubleshooting questions

[wpoll]

Often the ABS module faults are caused by the fine wires that connect the pins on the external connector to the internal circuit board failing. The same fault occurs on the M57TU glow plug controller. In the case of the glow plug controller, it's easy/cheap to replace the entire module (no coding etc.) - but it's not so easy with the ABS module.

Damage to the fine connecting wires is caused by a combination of heating/cooling cycles and vibration.

[andrewwynn]

Aka "bond wires" and they are welded not soldered so very difficult to DIY repair.

[c-bass]

Those wires look very 80s. I appreciate every time I see old school electronics how you can see a human soldered all those components and everything is so big.

Wonder why they chose to go that route, looks like old school tech mixed with

[andrewwynn]

Machine robot welding for speed equals faster equals cheaper. They just under estimated the required bond wire size or didn't engineer in enough stress relief.

In Navy Electronics school they taught us to put a 270° curl into through hole components if the holes are close to the end of the resistor etc. So smart and greatly improves reliability.



Those are from a nasa website showing some stress relief for soldering designs (I couldn't find the 270°; that's for when the through hole is too close to the ends you would have to make too sharp of bend.


If Bosch simply put a tiny zigzag into the bond wires we wouldn't be having this conversation.

They prob programmed the bond wires to be tight to not vibrate but everything ever is a spring they just changed the frequency while adding stress to the ends.

[c-bass]

Originally Posted by andrewwynn

Machine robot welding for speed equals faster equals cheaper. They just under estimated the required bond wire size or didn't engineer in enough stress relief.

In Navy Electronics school they taught us to put a 270° curl into through hole components if the holes are close to the end of the resistor etc. So smart and greatly improves reliability.



Those are from a nasa website showing some stress relief for soldering designs (I couldn't find the 270°; that's for when the through hole is too close to the ends you would have to make too sharp of bend.


If Bosch simply put a tiny zigzag into the bond wires we wouldn't be having this conversation.

They prob programmed the bond wires to be tight to not vibrate but everything ever is a spring they just changed the frequency while adding stress to the ends.

Very interesting.

I don't know much about electronic components or design and my soldering skills are fairly basic but I've always enjoyed messing around or trying to fix small electronics.

[Clavurion]

On this video you can see how the machine does wire bonding with ultrasonic welding.

They can be repaired by soldering with copper wire but you need special solder like Alusol and more heat than typical solder. Not recommended if you are not familiar with this.

https://www.youtube.com/watch?v=Nxum...l=ACtronicsLTD

[andrewwynn]

Perfect video to showcase the issue

[Henrym3]

You should check the pressure switch pressure when static ignition on engine off. Should read 0 bar if it doesn’t the light will be on. Then press brake pedal and should raise accordingly. If not as above then change the pressure switch.


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[Ozzy474]

All thank you for your comments and Merry Christmas! Wanted to follow up on some additional troubleshooting from yesterday.

1) through INPA, I verified the handbrake functions correctly, this isn't the issue.

2) completed the replacement of the front right (passenger) wheel speed sensor which occasionally threw a plausibility error, but as pointed out earlier in the thread the "brake" light in the gauge cluster was illuminated as "red" and not "yellow". Red typically means ABS module issues and yellow typically means wheel speed sensor issues. As an aside, it was a giant pain replacing the abs sensor. The original sensor was stuck in the hub and so brittle it disintegrated at both the connection to the car's wiring harness and broke off in the hub. Luckily I had a new pigtail connector on hand to replace where the ABS sensor hooks into the car's harness. Then after very carefully drilling out the old ABS sensor, cleaning the hub / magnetic ring, reinstalling the new Febi ABS sensor, I was able to rule out any wheel speed sensor issue. To aid in the troubleshooting I turned the X5 on without plugging in the abs sensor and immediately the Trifecta (with yellow brake light) appeared in the cluster. Makes sense since that's how it should be. I then plugged in the connector, put the wheel back on, lowered the car, and went for a test drive (After clearing the DSC codes). Upon starting the car before setting off, no Trifecta lights, but after putting the car into gear, the Trifecta (with red brake light) appeared.

3) checking the DSC codes once again return the inlet valve error, but no wheel speed errors (and I verified all wheel speed sensors report the same values when moving)

I will check the brake pressure sensor, but I'm pretty sure all signs point to the module at this point - especially thanks to the stubborn inlet valve error. Any other suggestions before I give in and order either a rebuilt or new abs module?

Thanks!

[andrewwynn]

My buddy from Boston has the exact same error I believe. We've been trying to squash the bug for quite a long time.

He's sending me his module to put in my car and see if the code will then show on my car