ABS Issue Resolved! Topic is solved

Post by **sleddriver** » 22 Mar 2018, 13:04

Sometimes when the code indicates a front, right sensor, it actually IS the front, right sensor.....not the controller!

For years, I've been going around and around with the ABS system. I've previously pulled the controller twice to repair bad solder joints as reported here. Last time I had to enlarge the copper pad area surrounding the two motor pins. I also wire-wrapped both pins at the base to strengthen the joint between PCB and pin. Over time, the ABS warning lamp would illuminate (along with its CEL devil twin P0-455 GROSS EVAP LEAK). I was beginning to think the issue was with the ABS connector itself. Even VADIS reports this can cause issues and recommends zip-tying the whole connector firmly shut. They've even provided a special slot just for this purpose!

Having often read "it's rarely the sensor...it's usually the controller". I took it as so. However, this statement ignores that which connects SENSOR and CONTROLLER: THE WIRING. Specifically the wiring in the wheel well.

I discovered a great pinout of the ABS connector and which wires to check on Mid-West's site: https://www.midwest-abs.com/Troubleshooting.php. Scroll all the way to the bottom for a picture. When using this, you'll have to flip left-for-right as we're probing the connector, not the controller. I used a felt marker so that when I turned the page over, I could still see what-was-what.

Lo & behold, FR showed an OPEN rather than the 1099 Ohms the rest did. Odd that....

I pulled the FR wheel to discover the wiring had been sheared off right at the sensor's red connector! The sled sees no off-road work. How the heck did that happen?? I was able to reuse one of the female 3.5mm protected bullet connectors by wrapping/soldering wire to it, but the other was too short. Thus my posts on obtaining new connectors (viewtopic.php?f=1&t=84719). The next problem was to find out if there actually WAS a connector on the other end of the wiring. I discovered an old thread that had never been answered: viewtopic.php?f=1&t=29272. That answer is no. The wire itself must be cut. Rather than have a splice down inside the wheel well, I added wire to put the splice in the engine compartment. I still needed to verify if this indeed was the solution.

I didn't have to go far, nor very fast, on my test drive to witness the ABS light going out! (Don't need to 'erase' ABS codes like CEL codes).

YES! FINALLY! Sometimes IT IS THE WIRING....

Post by **scot850** » 22 Mar 2018, 15:19

Man you have been fighting that issue for a while! Glad you got a solution finally for it, and very well done sir.

It reminds me of the V70 NA (my 2nd never ending project) and the multiple warning lights. Took a while to get there but eventually through process of elimination, it turned out to be the ABS controller and with a re-built unit from Matty at Mid-West ABS you mention, all was then good.

Now there is just that P0455 issue.......

Neil.

Post by **Matty Moo** » 22 Mar 2018, 18:20

When I test repaired modules I erase the stored codes as I do it. At least 15% show lone open circuit codes which shows an open circuit that isn't a module fault. That doesn't include the modules I test that have every possible code stored since you can't pick actual circuit faults out of those.

They're the only wires on the car that move anytime the car is moving, they wear out.

Post by **sleddriver** » 23 Mar 2018, 17:25

scot850 wrote: ↑22 Mar 2018, 15:19 Man you have been fighting that issue for a while! Glad you got a solution finally for it, and very well done sir......Now there is just that P0455 issue.......

Indeed I have! Holy Cow Meow.....RPITA. The light is STILL off. The dash panel actually looks odd....it's all dark.

And another thing....no CEL = P0455! No CEL period! Can't imagine what I did except mostly drop the tank and swear at it. I finally remembered to remove both battery cables, connect a large R between them and leave it that way for a few hrs. No CEL since.

Thanks for the pat-on-the-back Neil!

Thanks again to Mid-West for the pin-out!

Post by **sleddriver** » 26 Jun 2018, 21:46

scot850 wrote: ↑22 Mar 2018, 15:19 Man you have been fighting that issue for a while! Glad you got a solution finally for it, and very well done sir.

Now there is just that P0455 issue.......

Neil.

Just updated another post regarding P0455. The code hasn't returned since dropping the tank, cleaning and lubricating both fuel level sender & pump gaskets AND lub'ng the o-rings inside that small connector, found on the left side of the tank. Those o-rings were very, very dry.

Since then no more P0455!!! Plenty of time has elapsed for a Evap sys. check, heck multiple times. The dragon is finally DEAD! It took dropping the tank though, something that's never been done since she left the factory in Aug 1997.

Post by **abscate** » 27 Jun 2018, 01:42

Volvo tortures you with the sensor wiring on these cars

Up to 1999, you don’t get connectors on the front sensors

1999, you get a nice easy sensor test point on the strut tower, but the rear sensor is a one piece unit for both wheels that you have to fish tape around the gas tank.

Fugly

viewtopic.php?f=1&t=84246&hilit=Rear+abs+sensor

Post by **oragex** » 27 Jun 2018, 03:45

Not for this model, but on P2 2001 and up the sensor wire to the spindle is extremely fragile. The smallest pull on it will cause the wire to fail and get an ABS light. When removing the sensor (such as while replacing some suspension part), the sensor must be pressed up from underneath with a flat screwdriver once the little bolt is out - any pulling on the wire to remove the sensor from it's socket will result in a cracked wire.

Cookeh · Post by **Cookeh** » 16 Nov 2019, 08:39

sleddriver wrote: ↑22 Mar 2018, 13:04 I pulled the FR wheel to discover the wiring had been sheared off right at the sensor's red connector! The sled sees no off-road work. How the heck did that happen?? I was able to reuse one of the female 3.5mm protected bullet connectors by wrapping/soldering wire to it, but the other was too short. Thus my posts on obtaining new connectors (viewtopic.php?f=1&t=84719). The next problem was to find out if there actually WAS a connector on the other end of the wiring. I discovered an old thread that had never been answered: viewtopic.php?f=1&t=29272. That answer is no. The wire itself must be cut. Rather than have a splice down inside the wheel well, I added wire to put the splice in the engine compartment. I still needed to verify if this indeed was the solution.

Don't suppose you can recall where you spliced it and what you sliced it with? Can it be soldered in?