Before I payout for a second hand ABS ECU, someone has suggested checking the speed sensor on the back wheels.

Is there a guide for this as I do not know what I am looking for or how to check it.

rajveer.sandhu wrote on 24. Aug 2011 at 09:48:

Before I payout for a second hand ABS ECU, someone has suggested checking the speed sensor on the back wheels. Is there a guide for this as I do not know what I am looking for or how to check it.

The ABS sensors are the speed sensors. Can't remember specifically which sensor is used, ISR it was on a front wheel  :-/.

Isn't the speed signal on autobox used for auto cars?


If its a post 1998 car, it will be the ECU.

Well, on my car, the speedo follows the speed of the drivetrain and rear wheels during times of "limited traction". :-X

I'd be surprised if the autobox speed sensor was used as it'd have to communicate the speed via CAN to the ABS ECU and then there's the diff ratio which would have to be coded into one of the ECUs. More likely to use a combination of ABS wheel sensor inputs IMHO.

I think the ABS ECU will still generate a speed signal with failed sensors. As long as it's getting a signal from somewhere. So, agreed - the most likely cause is a failed ABS ECU.