95 850T Limp mode and codes after tranny swap - solved?

850TurboTurtle · Post by **850TurboTurtle** » 21 Sep 2015, 14:45

I put a 96 tranny in my 95 850T, and rigged up a wire pair from the driver's side wheel sensor to the now-unused harness connector which used to plug in behind the pax side axle to some speed sensor for the tranny. Theoretically this would allow my computer to still get speed data from the wheel.

However, now I am getting the following engine codes, and the car has defaulted to limp mode. Also, the ABS light is on:

A1: 2-3-2 Speedometer signal missing

A2: 1-1-1 Well at least the fuel system is happy

A3: 3-1-1 Transmission RPM signal missing

(these two are just instrument cluster codes I believe:)
A7: 1-1-3 Fuel gauge open circuit
1-2-2 Temp sensor interval too long

The wires are soldered in, and well wrapped with e-tape, so no shorts or bad connections. I took a 50/50 chance on polarity, but also was told there was no polarity for these hall sensor connections.

So it looks to me like the odds are the sensor connection is wrong. Does anyone have experience with this tranny swap situation and know what to check first? Thanks, all.

PS - here is the link to the previous thread on swapping these trannies and the speedo sensor jumper wire: https://www.matthewsvolvosite.com/forums ... =1&t=71559

850TurboTurtle · Post by **850TurboTurtle** » 22 Sep 2015, 13:34

Has anyone else out there put a 96 tranny on a 95 engine and had to deal with the speed sensor rewiring? Looking for some ideas. Thanks.

850TurboTurtle · Post by **850TurboTurtle** » 22 Sep 2015, 14:49

I did switch the polarity of the speedometer sensor wires (by desoldering and swapping the patch wires at the driver's side wheel well where they come off the sensor.) I now have speedo and the tranny works without throwing codes. Also, the ABS light has gone off and the brakes seem a little more solid (were a bit spongy before.)

However, the car is running very strangely with a lot of missing and power loss. If I floor it from idle it will not get up past 3500rpm and running roughly. If I don't floor it it will smoothly get up into the redline zone. When driving around the block, when accelerating from a stop, it starts up slowly, gets better, loses power around 20mph, and gets stronger around 40, then drops off again. Just in case anyone else ever looks at this thread with the same symptoms, I'll post the eventual solution.

850TurboTurtle · Post by **850TurboTurtle** » 25 Sep 2015, 19:47

The tranny was just fine: the additional problem was a loose hose in the fuel pump, so it wasn't developing enough fuel pressure (10psi rather than 40). Once that was repaired I tested it and chirped the tires pulling onto the freeway. The TurboTurtle rides again!!

So, the polarity swap on the tranny speedo sensor did the trick after all.

Post by **Ozark Lee** » 26 Sep 2015, 08:04

Great news. I was under the impression that the wheel sensors were analog and thus didn't care about polarity so I will have to file the polarity sensitivity in my memory bank.

...Lee