ABS Trifecta - troubleshooting questions

[Ozzy474]

Hello all - I have been troubleshooting the ABS trifecta issue on my 2001 BMW X5 5-speed, and it's about to drive me crazy. Any thoughts would be much appreciated. Below is a summary of what I've currently tried / where I'm at.

Symptoms: DSC light, ABS light on (yellow), brake light on (red) - henceforth known as the "Trifecta"

Circumstances: Weirdly enough - when the car is started there is no Trifecta and I'm able to toggle the DSC switch turning on and off the light in the gauge cluster. However - once I put the car in any forward gear and begin to move, the Trifecta come on immediately. This is consistent and has been like this for months. Very rarely (say once in ~50 starts) when I turn the car on without putting it into a forward gear the Trifecta will appear - only exception is the "brake" light appears yellow in the cluster. At which point it immediately changes to red upon selecting a forward gear.

Troubleshooting methodologies tried and parts replaced:

1) using INPA I initially could not communicate with the DSC module - which I believed signified that it had failed (speedometer and cruise control stopped working at the same time). I sent it off to be rebuilt by Matt Mallory at cheap-abs.com. Upon reinstallation the Trifecta appears as aforementioned above (but cruise / speedometer now function). The failure code that populated in INPA post ABS unit rebuild was an inlet valve error (DSC error code 54 for valve inlet front left).

2) I've lived with this problem for a few months and now have finally had time to tackle it again. I checked again in INPA to see if any new codes in the DSC module had popped up and a few had. Both plausibility codes related to the front right wheel speed sensor and rear left wheel speed sensor. Through INPA, I viewed in real time the wheel speed sensors. All where operating at a consistent speed with no obvious issues.

3) since speed sensors are cheap compared to a new ABS module, I purchased two new speed sensors from ECS Tuning (Febi brand) along with new pigtail connectors where the sensors hook into the car's wiring harness since those are usually brittle with age. Today I replaced the driver rear speed sensor just to rule out the plausibly error and replaced the pigtail. Went for a drive after and the issue still exists, but the plausibility errors hadn't returned to any speed sensor after I had cleared the DSC error codes the first time. The inlet valve error remained.

4) at this point I'm about 99.9% sure the ABS module is faulty and was too far gone to be repaired properly. Since I already have the front right wheel speed sensor, I'm going to go ahead and replace it for the avoidance of any doubt.

Question to the Forum at large:

What are your thoughts? Do you agree it is likely a bad ABS module? Is there a chance it could be the ABS pump that's failed? Through my research I've not found any forum postings where the ABS pump / valve block has failed. Could it be anything else I'm not considering?

Finally the second part to the question is IF it's the ABS module, any recommendations where to source one? I've had trouble locating any new stock (e.g. FCP Euro shows it out of stock, not to mention it's major $$$). Thoughts on trying to find a rebuilt unit? I understand either a new or rebuilt unit will require some coding which isn't an issue for me to handle.

Final parting thought:

If this X5 wasn't such an oddball (5 speed manual with cold weather package / heated steering wheel / rear climate package) I'd consider just leaving things as-is, but I find myself driving it too often and hate staring at the Trifecta. Any thoughts are very much appreciated - thank you in advance!

[andrewwynn]

Talk to the guys at cheap abs. The error you describe is indicative of internal fault exactly the type they repair.

The red brake is the key. Yellow usually means external sensor fault red indicates internal module fault or transfer case fault but I'm not aware of those happening on pre x-drive.

[Ozzy474]

@andrewwynn - thank you for the response. I did have quite a bit of back and forth with them. Ultimately they did refund my repair fee less shipping, but were in the mindset that they had fixed the module, but did acknowledge that in certain circumstances a repaired module could still have an inlet error if it was too damaged. They did fix the communication error with the module though so it definitely was damaged. They mentioned it could be the abs pump causing the error, but that seemed unlikely to me that the abs pump and module would have failed at the exact same time.

Thank you for the clarity on the difference between the yellow and red brake light.

[andrewwynn]

The other reasons for red trifecta: hand brake or low fluid so check those are working properly. I think you mentioned scanner capability that should be able to read the switches.

[andrewwynn]

Coincidentally I have a module with I think the same error headed my way that I'm going to put in my car to rule out an external defect. (looking to have the same error show up when swapping out my working module). Been trying to squash a trifecta that's existed since purchase from a buddy in Boston.

Any other errors like dashboard lights persistent?

[upallnight]

Originally Posted by andrewwynn

Coincidentally I have a module with I think the same error headed my way that I'm going to put in my car to rule out an external defect. (looking to have the same error show up when swapping out my working module). Been trying to squash a trifecta that's existed since purchase from a buddy in Boston.

Any other errors like dashboard lights persistent?

Friends don't sell BMW with problems to a friend.

[andrewwynn]

But friends both with BMW will help the other figure out problems. You misread that. Friend that lives in Boston bought his own X5. When he bought it already had trifecta. The part is coming from Boston not the trifecta car. That is staying in Boston.

[puddinboo]

Are these modules in a spot where they are susceptible to water? Is that why some BMWs have this issue?

2003 BMW X5 E53 M54 engine,253512KM

[andrewwynn]

No: heat. Heat kills and it's too close to the engine. Also too close to the shock of the suspension.

I have had my abs temporarily knocked out from a big puddle but that was a wss connector problem.

[puddinboo]

Heat will do it for sure,and why put it in areas like that,must be a better place to put these modules.

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