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Old 06-15-2009, 04:02 PM
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bluebee bluebee is offline
Seek to understand,^Value
Location: San Jose, California
Join Date: Mar 2008
Posts: 25,236
Mein Auto: 02 BMW 525i M54 auto 130K
Originally Posted by 540iman View Post
Mine swung up to just a hair over 4 VDC with full brake pressure. it was about .4VDC with no brake applied.
OK. Let's get back on track. This thread is about two things:
1. How one would, in general, debug ABS issues (mostly this updated post)
2. My particular saga (which follows & updates the diagnostic procedure in #1 above)

- ABS/BRAKE/DSC lights are still lit (so I have not solved anything yet)
- All four wheel sensors tested good (thanks 540iman for the definitive tests!)
- Diagnostic tools first indicated a Bosch "114 Pressure Sensor Offset"
- Now they implicate a BMW "81 Einlassventil : vorne links (inlet valve, front left)"
- I ordered the pins to test the brake pressure sensor (but I don't think it's that anymore 'cuz the diagnostic tools no longer implicate it).
- Nobody seems to know what an "inlet valve, front left" is, let alone how to test it.

- I plan on testing the brake pressure sensor and reporting the results (thanks for your comparison results!)
- I hope to locate the "inlet valve, front left" and test it (somehow)
- If both test good, I plan on sending my ABS control module out for a rebuild

So, the main unanswered questions is ...

What is an "inlet valve, front left" and how does one test it?

NOTE: I'm googling for the following and tracking down the references:
"inlet valve, front left" bmw abs

It looks like it might be an abnormal solenoid valve circuit(s) in the ABS control module or hydraulic unit. Apparently test voltage must be 0V with valves off and 12V with valve on (the inlet and outlet valves are active for short times only during ABS modulation).

Last edited by bluebee; 06-16-2009 at 11:13 AM.
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