can speed sensor be connected to ABS and ECU ?

I want to use to ABS speed sensors (from all 4 wheels) and to connect it to the ECU (haltech elite 2500).

The ABS unit is an old ATE 91BB which is a standalone system.

Was thinking to attached each each speed sensor to SPI input (SPI 1 to 4 on the pic attached) and also to connect the speed sensors to the ABS system itself (same speed sensor will be use to send info to the ECU and ABS system).

Any idea is this will work and will be safe and accurate as much as this old system can be?

Hello Nadav,

Piggybacking ABS WSS can cause issues with the function of the ABS, so I don't recommend it if you intend on keeping the ABS. What vehicle are you working on?

ford sierra cosworth

Does the transmission have an output speed sensor? If it does that can be used for the speed signal. Otherwise a driveshaft collar & speed sensor or GPS speed input could be used. Alternatively you could contact Haltech & see what they suggest with regards to using an ABS WSS. There is an RPM drop, per gear, that can be used for gears detection in the Haltech software but I don't know how that will work with heel'n'toe downshifts.

It seems quite a few people have connected up this way without issue, though I don't personally like it as could affect abs function. Assuming the sierra has variable recluctor sensors, vr+ would tee off to your spi while vr- to sensor ground.

I've used a cheap vr to hall sensor converter for my project (just 1 front plus gearbox output) which does not affect abs function, so that option also exists. The best option I found no longer ships to Aus though so I will be trying for myself connecting the tee'd off ABS vr sensor on my bros front wheel for basic speed based functions... Spi's are too precious to waste on 4 wheel traction control imho lol.