In this blog post we talk about the Anti-Lock Brake System (ABS) in your Subaru, ABS Deletes, and how the car is impacted when those signals are removed.
What does ABS stand for?
Anti-lock Brake System. The fastest way to stop a vehicle is to not slide (even if that's not as fun). The best way to do that is to sense if the wheels are going to lock up and release the brakes accordingly (the ABS pulses on/off). We recommend keeping this system intact for most instances because although on the track the driver can modulate for the conditions, the idea that it would be possible to modulate braking in an emergency situation is pretty far fetched.
Why would you do an ABS delete?
The simple answer - because "racecar" or "tucked engine bay". If the goal is racing the car and you want to modulate the brakes, the driver doesn’t want the outside influence of the ABS to have an impact. All of the braking is being done by hand (or by foot LOL). The ABS might come into play when the driver doesn't want it to so the system is removed entirely. Some people also delete the ABS pump for a cooler/cleaner looking engine bay.
ABS and CANbus
When it comes to CANbus, it's best to leave the car as stock as possible. Once needed inputs start being removed from the CAN system, complications occur. The ABS pulls the wheel speed and kicks it out via CAN to the different modules in the car like the ECU, cluster, and body module. Without this wheel speed input, the ECU won't run properly. We recommend keeping the ABS system intact for most cars with CANbus systems.
When it comes to the OEM DCCD system, the ABS inputs are used to identify the wheel speed so the controller can adjust on the fly. To maintain the stock DCCD system, ABS has to function correctly. If using an aftermarket DCCD controller the ABS is not needed.
In older non CANbus cars the transmission gets wheel speed inputs from a direct signal using a gear in the transmission to the ECU/Cluster so they can function just fine without the ABS input. However, If a transmission from a CANBUS car is installed into an older car (think a 2011 STi transmission into a 2004 WRX), a VSSPro is needed to replicate the speed signal using the ABS for a wheel speed signal, that would have been in the transmission that is no longer there. This doesn't actually require the ABS pump to be in there, just a wheel speed sensor to feed the VSSPro the necessary input.
How to get around ABS with a CANbus Car
As mentioned above, in CANbus cars the ABS is pulling the wheel speed information and feeding it to the rest of the car. Without wheel speed, the ECU won’t work properly which makes the logistics of an ABS delete on a CANbus car pretty difficult. For those building a race car in a CANbus equipped chassis and the ABS must be deleted, we suggest a non CANbus ECU or a standalone ECU that does not require these inputs.
There are a few connector types for the ABS system. Click on the image below to purchase the connector you need.