ABS Trifecta - troubleshooting questions

[Henrym3]

Because this is an ABS post I will relate how my problem was resolved. After diagnostics with a number of faults (can’t remember the codes) I sent my ABS module of to ECU TESTING as it had previously been repaired by them and was under lifetime limited warranty. Got it back saying they couldn’t find a fault but had "tidied it up ". Still had the fault. They asked for the complete pump and module. This came back with no faults. Refitted and still had same fault. They asked for the module again and this time informed me the module was toast and beyond repair?? All of this was free of charge, they sent their own courier. They offered me my original £240 repair cost back (from 2 years previously) or a brand new module which they would upgrade to their standard for an additional £150 but I would have to wait 2 weeks for them to get one. I agreed. Got new module. Same fault. Finally looked at brake pressure and found that static I was getting a reading of 192 bar pressure. Googled the p/n and found the switch was fitted to a number of cars ie Volvo/VW and some others. Went to recycler and got the part from a VW Passat £2 and fitted. Static pressure 0. All warning lights gone. No more problems. I probably didn’t need the new module, but what price some good knowledge. I considered ECU Tuning were more than fair in how they dealt with me.


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[Boston01X5]

Just read this thread, lots of good info. I’m the friend who sent Andrew a module to swap. Been dealing with trifecta since purchasing my X5, have tried numerous things like the OP has. OP hope you get your issue resolved soon, and let us know what solution was. Like you said, trifecta always on drives you crazy after a while lol

[Ozzy474]

@Boston01X5 - yes, will definitely post a resolution once (assuming if) I can get this resolved. I read through another thread where someone had a similar issue as mine (no Trifecta on until the car is put into gear and moves a few feet), the explanation in that thread was that apparently the X5 does an abs system check in roughly the first 50 feet of travel. This explains why my Trifecta only appears after beginning to move the X5 rather than immediately upon start up. That must mean the system thinks everything is fine until it actually tries to engage the ABS system / module at which point it detects a problem (e.g. inlet valve error). Is your issue also a valve error?

@Henrym3 - do you happen to remember what error you had? Was it by chance a valve error?

[andrewwynn]

I think that the error is valve relay error. I think it's a bond wire problem but at the age of these things could easily be solid state error.

[Henrym3]

Originally Posted by Ozzy474

@Boston01X5 - yes, will definitely post a resolution once (assuming if) I can get this resolved. I read through another thread where someone had a similar issue as mine (no Trifecta on until the car is put into gear and moves a few feet), the explanation in that thread was that apparently the X5 does an abs system check in roughly the first 50 feet of travel. This explains why my Trifecta only appears after beginning to move the X5 rather than immediately upon start up. That must mean the system thinks everything is fine until it actually tries to engage the ABS system / module at which point it detects a problem (e.g. inlet valve error). Is your issue also a valve error?



@Henrym3 - do you happen to remember what error you had? Was it by chance a valve error?

Yes it was valve errors, should have kept notes but got so pissed off with sending things back and forward. To be honest I was getting desperate as all the experts were telling me there was no faults. In the end it was so simple you always wonder why the hell you didn’t check that first. To be fair I hadn’t read anywhere about pressure testing, just seen it listed on my Foxwell and then thought it didn’t seem right to be getting massive pressure without the engine running. Took a wild assed guess and changed the pressure switch.


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[Boston01X5]

Originally Posted by Henrym3

Yes it was valve errors, should have kept notes but got so pissed off with sending things back and forward. To be honest I was getting desperate as all the experts were telling me there was no faults. In the end it was so simple you always wonder why the hell you didn’t check that first. To be fair I hadn’t read anywhere about pressure testing, just seen it listed on my Foxwell and then thought it didn’t seem right to be getting massive pressure without the engine running. Took a wild assed guess and changed the pressure switch.


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When I saw this post a few minutes ago I went outside and hooked up Foxwell and brake pressure reads just fine. 0-40 Bar. I was hoping this was the cause of my trifecta but wasn’t that lucky. Thanks for the tip though. Definitely worth taking a minute and ruling that out since it’s so easy.

[Clavurion]

Originally Posted by Henrym3

Yes it was valve errors, should have kept notes but got so pissed off with sending things back and forward. To be honest I was getting desperate as all the experts were telling me there was no faults. In the end it was so simple you always wonder why the hell you didn’t check that first. To be fair I hadn’t read anywhere about pressure testing, just seen it listed on my Foxwell and then thought it didn’t seem right to be getting massive pressure without the engine running. Took a wild assed guess and changed the pressure switch.

So you are talking about the pressure sensor at the back of hydraulic block?



Some info regarding the pressure sensor.

https://www.pss-autosoft.net/diagram...-3450-005C.htm

[Clavurion]

Valve errors can be caused by failed valve itself on the hydraulic block (very rare), coil driving the valve (rare) or components on the control module driving the coil (most common). Unfortunately in many cases the base problem has been failing internal ground wiring on the module (same type welded wiring as for wheel speed sensors) which when abruptly cutting power eventually causes component failure which many refurbishing companies deem beyond repair.

[Henrym3]

Yep, that’s the one on the back.


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[Henrym3]

That’s an interesting read. Didn’t know any of that. So is ignorance bliss or I just got lucky? I find it amazing that there is no tolerance in the test pressure. Below 80bar it’s the switch above it’s the pump.
Just as an add, there was very little loss of fluid when I changed the switch although I had the replacement one ready to put in straight away. I also bled the brakes again


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