ABS 045 - Left Rear Sensor Bad Output

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coors66

Member
Sep 17, 2012
12
0
Philly
I've been throwing ABS fault 045 "left rear sensor low output" for a few days.

This afternoon, after clearing the code and replacing the sensor - it returned. This time as "left rear sensor Bad Output". I Swapped the sensor with a known good one from my parts truck And the first bump I hit after install during a "test drive" the "four Amigos" illuminated again. Same code, 045, "left rear sensor bad output".

It seems every time I hit a bump in the road (after clearing the code) the ABS TC HDC and Brake light illuminate.
I'm stumped...

I performed a resistance test on the replacement sensor prior to installing, I think it read roughly 1020 ohms. In the limits of specified range. I think optimal range is within ~950 - ~1120 ohms. The reading bounced around a bit as I tapped the sensor against metal...

What should I be looking for?

* trace wire back to SLABS - inspect for ground faults along chassis?
* bad wheel hub? What makes up the hub? A bearing and casing? I don't believe the bearing is worn.
* fault at connector at SLABS unit?
 
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discostew

Well-known member
Sep 14, 2010
7,735
1,026
Northern Illinois
I think you probably have a bad hub.There is a overlay harness available that runs from the connector all the way to the slabs ecu. Make sure you have the new sensor seated properly and the o ring didn't get out of place
and keep the sensor out of the hole.
 
rovercanus

rovercanus

Well-known member
Apr 24, 2004
9,651
246
I hate it when I agree with Stew. Even though it is yummy on a cold winters day.
 
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coors66

Member
Sep 17, 2012
12
0
Philly
Thanks for the help fellas. Who knows if the sensors are Hall Effect or Magnetic?

There is a theory,
Hall Effect ABS sensors on some models is triggered by tiny magnets with in the wheel bearing oil seal - degradation of the wheel bearing and its' integral seal can caused loss of signal from the sensor.

Before I sell off a kidney to fund the purchase a new hub assembly I want to be as sure as possible the hub/bearing is failing up he ABS signal. Unfortunately, I don't have waveform/lab scope at my disposal...
 
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coors66

Member
Sep 17, 2012
12
0
Philly
I'm 99.9% certain these are magnetic sensors. Regardless, I believe the theory above holds true. Off to carve out my Kidney...
 
jymmiejamz

jymmiejamz

Well-known member
Dec 5, 2004
6,008
361
35
Los Angeles, Ca
Before doing the overlay or replacing the hub, I would cut out the connector in the wheel well and hard wire the sensor to the harness. The overlay harness just eliminates that connector. I've fixed a bunch like this.
 
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coors66

Member
Sep 17, 2012
12
0
Philly
jymmiejamz said:
Before doing the overlay or replacing the hub, I would cut out the connector in the wheel well and hard wire the sensor to the harness. The overlay harness just eliminates that connector. I've fixed a bunch like this.
Click to expand...

I should have listened...

Replaced hub (Britpart - came w/ new sensor), cleared the code(s) ECU 1590 and SLABS 045. Drove for approximately 45 miles without issue going through all types of driving; Highway speeds, hard braking, left and right turns down suburba streets, down bumpy alleys etc...

All seemed fine so headed home - then, driving down my street...the 4 Amigos light up.

Anyone ever experience or hear about certain brake pads causing nuisance ABS issues?
 
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coors66

Member
Sep 17, 2012
12
0
Philly
After three days of driving I think I have it sorted. I found the ABS connector not fully seated. I remember having a helluva time fully seating it during install. I gues I said to myself, " that's good enough", leaving a micro gap between the connectors. Apparently, not.

I disconnect and reconnected the connector this time making sure to leave no gap. It's been fine.

Award goes to Stew
 
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