P1027 not ABS what next?

Post by **precopster** » 30 Oct 2012, 05:01

I have been battling a speed sensor fault on the '99 V70 project car for a couple of months now.

To give some history this V70 has a 850 '96 four speed with the speed sensor from the original 'box. So it should work OK. Everything I've read until now tells me I should be fine with the older gearbox as long as I use the '99 speed sensor.

The ABS unit is fine and has been swapped into the 2000 V70 and doesn't give any problems. As soon as the car reaches speed of say 35-40mph the speed sensor fault comes back. It shows as a DTC transmission code when read with a generic scanner. When read with Vida it's ECM-530D and two TCM codes 0023 and 0087 relating to speed sensor signal not present and too high. Should I get a new speed sensor or is there something I'm missing?

Sure would appreciate any thoughts or leads on this one as I've booked it in for next Monday at a specialist that usually takes $$$$ for sneezing in his direction (though I do trust these guys) and right now things are tough here.

Post by **jimmy57** » 30 Oct 2012, 08:16

Did you change both speed sensors to have both from original box on the trans in car now?

Post by **precopster** » 30 Oct 2012, 14:37

Didn't know there were 2 sensors. Only swapped the one up on top of the trans behind PNP right up close to the firewall. Where's the other located?

OK just had a look at the old gearbox and I can see the second one. The penny is now dropping....

Post by **precopster** » 30 Oct 2012, 14:59

It looks easier to cut and solder the 2nd one in because it's wired into the PNP connector, though this would give me a chance to swap the entire assembly out and clean the original PNP out (which has 160k miles)

The PNP in the car now only has 65k miles so I could leave it for a while if I solder.

Post by **precopster** » 10 Nov 2012, 01:58

There's the correct speed sensor on the right for a '99 V70 and on the left the 850 speed sensor. The PNP connector splits into 4 sections so each switch can be wired in independantly. That speed sensor has the yellow wires.

I cleared the P1027 code and took her for a spin. No more codes!!

Thanks so much jimmy. I wouldn't have thought of another speed sensor without your input.