1998 S70 Speedometer and odometer quit

marcusheard · Post by **marcusheard** » 21 Aug 2013, 22:10

Hi, my speedometer and odometer stopped working. I replaced a steering knuckle last year and the knuckle was not from a 1998 as advertised on Ebay, so my abs sensor did not match.

However I installed the knuckle anyway since I accidentally destroyed that abs sensor while removing my old knuckle. To this day that front knuckle is missing an ABS sensor - I replace that sensor when I have time to pull that incorrect knuckle off.

I road with my ABS TRACS light on for several months without any problems, until I took my car in for a state inspection sticker. Upon leaving the shop I noticed my speedometer and odometer failure.

Before I spend $220 on a new ABS module, I'm wondering if any other parts can cause such symptoms - its a little suspicious that my problem began after leaving a repair shop. I opened my ABS module and the contacts looked decent, I soldered a few anyway, and my speedometer and odometer is still out of service.

Thanks for any advice

Post by **Matty Moo** » 22 Aug 2013, 04:52

The abs system uses both front wheel sensors to determine the speed of the car. It will still do it with only one wheel sensor but once you lose the signal from both it stops. You lost one automatically with the knuckle swap and the other dropped out from either the module being at fault or the sensor.

When you solder it, you have to hit both power pins feeding the abs pump and the bulk of the smaller 21 pins.

marcusheard · Post by **marcusheard** » 24 Aug 2013, 18:14

ok, I just installed a rebuilt ABS module that I purchased on ebay for $100, and my speedometer and odometer are still out. I'm moving on to my front wheel sensor next.

Does anyone know the ohms resistance for an ABS sensor on a 1998 S70? I'm thinking that since I only have one sensor connected up front (on passenger side), that one sensor must have gone bad (or there is a loose wire).

Thanks for any assistance

Post by **Matty Moo** » 24 Aug 2013, 19:30

You would be ahead of the game by repairing your unit properly, fixing the sensor and going from there.

marcusheard · Post by **marcusheard** » 01 Sep 2013, 11:38

ok, after attempting to unplug my front wheel sensor from its harness the wires simply disintegrated - the sockets inside of the harness are practically glued in place by scale and residue. I just ordered a used sensor still in its harness for $35 and it will arrive next week. The last owner lived in Ohio, so its safe to say that my old car has been exposed to a lot of road salt.