Diagnose ABS problem

[WpgDSMer]

My ABS light started to come on a while ago, intermittently. It is now on all the time, and my ABS is not working. I tried to read the trouble codes, but could not get any. I had the dealer look at it twice, and they could not read any codes. I tried one more time, but still could not read any. I've owned the car for a long time (10 yrs) and the last time this happened (when I first got it) it turned out to be the ABS ECU (it was a warranty thing, so I didn't look to closely into it).
An ABS ECU from the dealer is very expensive, so I want to make sure that's it. I've gone through the Voltage check, and the harness resistance check, and I'm getting some strange values. Could anyone look at this and see what they think the issue might be? It looks like a few things, which makes me think it might be the ECU, but the bad harness values worry me (since the ABS ECU isn't attached when you check those).

Voltage Check (with ignition on)
terminal 2 - 12.33v (should be battery voltage) OK - Relay Power Supply (output)
terminal 6 - 2.48v (should be 2.3-2.7v on level ground) OK - G sensor (input)
terminal 17 - 0.01v (should be battery voltage) - FL(RR) solenoid valve (output)
terminal 18 - 12.35v (should be battery voltage) OK - Ignition switch (input)
terminal 22 - 0v (should be battery voltage) - Valve relay monitor (input)
terminal 23 - 11.33v (should be 1v or less) - Diagnostic communication (input/output)
terminal 24 - 11.13v (should be approx 12) OKish - Diagnostic selection (input)
terminal 25 - 0.80v (should be battery voltage) - ABS warning light (Output)
terminal 29 (ignition off, stoplight switch off) - 0v (should be 1.5v or more) - Stop light switch (input)
terminal 35 - 0v (should be battery voltage) FR(RL) solenoid valve (output)

Wire Harness resistances
terminal 5 - ground : 19k ohm (should be 0) Motor Monitor
terminal 9 - ground: 0 ohm (should be 0) OK - ABS-ECU ground
terminal 10-11 : 1.138k ohm (should be 1.0 to 1.2k ohm) OK - RL sensor
terminal 20 - ground: not continuous (should be 0) G sensor ground
terminal 26-2: 80 ohm (should be approx 50) Motor relay
terminal 27-2: 105 ohm (should be approx 100) OK - Valve relay
terminal 30-28: 1.107k ohm (should be 1.0 to 1.2k ohm) OK - RR Sensor
terminal 32-15: 1.137k ohm (should be 1.0 to 1.2k ohm) OK - FL sensor
terminal 33-31: 1.101k ohm (should be 1.0 to 1.2k ohm) OK - FR sensor
terminal 34-ground: 0 ohm (should be 0) OK - ABS ECU ground

So there are lots of items that don't seem to match the normal values.
It looks like there is an issue with the valve (or relay at least), possibly the motor, the diagnostic voltages are out, and something with the G sensor ground (even thou the voltage, terminal 6, reads OK). I have DSMLink V2 running on the car, so I'm not sure if that would mess with the diagnostics port for ABS (I don't think so, but not sure).

None of the wire connections look burnt, and all seem to have a good crimp. I've taken out the ABS ECU and opened the case. None of the components look bad (not burnt or loose) and there are no traces that look bad. I have some pics of the inside of the ECU if anyone wants to see them.

Anyone have an idea?

 

[1LE]

Usually it's just a flaky wheel sensor. However, there's an TSB for wiring harness corrosion in the driver's side front wheelwell that can lead to ABS failure, did you do that TSB yet?

 

[WpgDSMer]

Usually it's just a flaky wheel sensor. However, there's an TSB for wiring harness corrosion in the driver's side front wheelwell that can lead to ABS failure, did you do that TSB yet?

I haven't seen the TSB for that. I'm going to see if I can get a hold of a different ECU to try it out and see if that's the issue.
If you have a link to that TSB I'd like to see it. Otherwise I'll just take a look at the wiring up there and see if there is anything I can find.

 

[1LE]

Unfortunately, it's been a few years since I saw the TSB and inspected my wiring there. A couple quick googles didn't turn it up. Not sure exactly how I found it in the first place, but I believe it was some website that had lists of recalls AND TSBs for all kinds of cars. Came across it while working on a melted wiring repair and I just happened to already have that section of harness pulled out, so I inspected the junction per the TSB (my ABS has never worked consistently since I've owned the car). I had no signs of the corrosion that the TSB warned of, so I just sealed it up and put it back.

All I can recall right now is that it involved some wiring in the driver's side front wheel well, right up in the fender, somewhere between the "middle" and the firewall. Pain in the rear to get at (but I had no choice as I was replacing melted parking/gauge power wiring anyways), and mine was perfectly fine, but I guess enough cars had the problem there to make it worth a TSB... Given the pain that it is, I'd save it as your last resort...

Never did get my ABS fixed, my wheel sensors are so heavily rusted in place I gave up at that point as I was going to break lots of stuff trying to get them out for testing. I've got a switch inline with power to the ABS computer and just leave it "off" all the time. I'd rather *know* I don't have ABS than wonder if it's going to work or not...