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abs module

Help, Advice and DIY Tutorials on Volvo's extremely popular car line -- Volvo's 1990s "bread and butter" cars -- powered by the ubiquitous and durable Volvo inline 5-cylinder engine.

1992 - 1997 850, including 850 R, 850 T-5R, 850 T-5, 850 GLT
1997 - 2000 S70, S70 AWD
1997 - 2000 V70, V70 AWD
1997 - 2000 V70-XC
1997 - 2004 C70

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jsloden
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Year and Model: 1998 C70 coupe
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abs module

Post by jsloden »

I have a 98 c70 coupe with tracs. I purchased am abs module about 2 or 3 months ago from ebay that was supposedly repaired. I installed in in the car and the speedometer and odometer started working but the abs and tracs lights were still on. Anyway, contacting the seller did no good and I was just happy to be able to tell how fast I was going again. Anyway, I noticed a local wrecking yard had a 98 s70 with tracs today so I grabbed the abs module from it. Same story, Speedometer and odometer still work, but the abs and tracs lights are still on. Is there anything that will turn both of those lights on but still allow the speedometer and odometer to work perfectly fine?

Thanks

jeffsws
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Post by jeffsws »

Did you drive the car after installing the abs unit? I think the car does a self diagnose test around 10 mph. Last year I had to disconnect the ABS connector at the wheel, when connecting it again the light did not turn off until I drove the car later.

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RickHaleParker
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Post by RickHaleParker »

You may actually have a defect in one of the ABS wheel speed sensors. Use VOL-FCR or 850 OBD-II to read then clear the codes and see what comes back.
1998 C70, B5234T3, 16T, AW50-42, Bosch Motronic 4.4, Special Edition package.
2003 S40, B4204T3, 14T twin scroll AW55-50/51SN, Siemens EMS 2000.
2004 S60R, B8444S TF80 AWD. Yamaha V8 conversion
2005 XC90 T6 Executive, B6294T, 4T65 AWD, Bosch Motronic 7.0.

jsloden
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Post by jsloden »

I actually tore the wiring for the front abs sensor when I was doing the front suspension with it disconnected I was not even getting a speedometer reading. I will take them all off and clean them though. Maybe that will help.

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jsloden
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Post by jsloden »

Ok, I cleaned the abs sensors. Before when I would take a turn while braking you could feel a vibration in the pedal like the abs was kicking on. It wouldn't matter what speed I was going. I took all of the abs sensors off and cleaned them. The car drives much better. The abs doesn't kick on any more. The lights are still on though. Anyone got any ideas?

Thanks

Matty Moo
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Post by Matty Moo »

A solid 25% of my core returns come back with stored codes that show actual lone open circuits on wheel sensors, low/high voltage codes and missing/blown fuses.

Take a 20 year old car and remember that the only wires that move when the car moves are the wheel speed sensor circuits. MOST of those wires break INSIDE the sheath so a visual shows they are good.
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http://www.midwest-abs.com
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1996 850 Platinum Wagon. ARD Green Tune, OBX.-Gone
1998 s70 ARD tune, EST exhaust, SE/R interior.
1999 s70 Plain Jane.
2000 s70 GLT
2014 Ram
2012 Jeep Wrangler Unlimited

jsloden
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Post by jsloden »

So I should check for voltage and each wheel sensor. I'm guessing only one wire will have voltage going to it since it works like a loop? I guess I can check the rear ones where they plug into the main harness? I checked the fuses and they were good.

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Matty Moo
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Post by Matty Moo »

If you tore one of the front wires doing suspension work then there is your problem. If you repaired it and used butt connectors that's still the problem.

You're checking for continuity to see a complete circuit.
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http://www.midwest-abs.com
Simplycleanpowerwash.com

1996 850 Platinum Wagon. ARD Green Tune, OBX.-Gone
1998 s70 ARD tune, EST exhaust, SE/R interior.
1999 s70 Plain Jane.
2000 s70 GLT
2014 Ram
2012 Jeep Wrangler Unlimited

jsloden
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Year and Model: 1998 C70 coupe
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Post by jsloden »

Nope, no butt connectors. Soldered them back together. By the way, the module wasn't supposedly rebuilt by you Matty. It was supposedly rebuilt by BBA. I just wish they stood behind their products as well as you do. They wouldn't do a return because I didn't purchase it from them. It still has their sticker right on it. But that doesn't really appear to be my problem anyway I suppose.

scot850
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Post by scot850 »

I had a nightmare with my 2000 V70 NA project. Had random failure lights coming on on the dash. Couldn't identify the root cause. Pulled another unit from PnP and fitted it. It turned out to be faulty also, but at least there was only one failure mode and it was repeatable. Bought a Matty Moo rebuilt unit (at least my third) and it worked great. If you are getting the exact same error messages from the car (and yes you have to get them pulled somehow) then it is probably unlikely the ABS module itself. Can be rust on the reluctor rings on the axle ends that the abs sensors use to operate. Rust can cause then to also crack which will cause issues with errors.

At this point I would suggest finding a way to get the code(s) read so you have a better chance of finding the root issue.

Neil.
2000 V70 R - still being an endless PITA
2006 XC70
2003 Toyota 4Runner V8 Limited
2015 Kia Sportage EX-L
1993 850 GLT -Sold
1998 V70 XC - Sold
1997 Volvo 850 SE NA - Went to niece in California - Sold
2000 V70 SE NA - New project and test bed - Sold

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