Speedometer not working and VSS A code

Mabes101 · Post by **Mabes101** » 20 Nov 2018, 06:02

Hello everyone,

I know there are some related topics to this out there but I haven't been able to find what I'm looking for so maybe time to start from scratch.
Car: 1995 Volvo 850 Turbo
Problem: Speedometer and Odometer on 1995 Volvo 850 cluster do not work. Everything else on cluster does function properly. I am also getting a Vehicle Speed Sensor code A. I threw in a ABS module a few day ago from a JY car and did a hard reset on the car. I don't have an ABS or Tracs light, just the CEL and flashing arrow (Doesn't seem related to PNP switch)

What I am wondering is if I have taken a cluster from another 850 Turbo and swapped into my car, will this also cause a the VSS code and a dead speedometer. I believe the car that the current cluster came from was a 1995 850 Turbo, and clusters look identical. Will the ECU recognize the change and throw the code?

Post by **Ozark Lee** » 23 Nov 2018, 07:19

On a '95 the VSS signal comes from the sensor on the transaxle, not the ABS module. The ABS modules pre-'96 are not typically problematic.

As I recall the sensor is screwed into the transaxle on what could be described as the lower right when you are under the car looking up. Check the wiring to the sensor and, push comes to shove, replace the sensor itself if the wiring is OK.

...Lee

Post by **jimmy57** » 23 Nov 2018, 07:34

That sensor is pointed at the firewall on the absolute rearmost part of transaxle. If you find where the drive axles to wheels insert in to trans, the sensor is on the back of that part of transaxle. One bolt holds it in. It is sealed by an O ring and has a two wire plug. It uses an older style connector with round "bullet" pins on the sensor and socket/sleeve connectors on the wiring harness plug. The socket connectors are covered with an injection molded clear plastic and that plastic can crumble with age and the plastic connector housing no longer is able to assure the connections stay together.
First check is to assure it is plugged in. If in doubt, push the wires toward sensor and see if they move onto pins. If so, then do that and go drive it to see if it is fixed. If that is it then you may have an unused 2 wire plug down by the windshield washer tank and that can be cut and used to splice onto the wires to sensor.
If wires are secure on the sensor then the sensor is the problem and they do have a history of failing.

Mabes101 · Post by **Mabes101** » 24 Nov 2018, 06:09

Thanks everyone,

Upon closer inspection the wiring of the cluster I tried to swap in was a bit different. I threw in the old cluster and sure enough the VSS code is gone and all guages were working again excluding the odometer (chipped gear).