in my fiat punto (51 plate) i had the abs light on constantly. This could simply be down to having a dirt covered ABS sensor or the ABS sensor just being damaged. I paid about £30 for an aftermarket ABS sensor. its a simple fix and shouldn't be too costly.
To change the ABS system on a 1990 Toronado Trofeo, you'll need to locate the ABS unit, typically mounted near the master cylinder or firewall, disconnect the battery, remove the old ABS unit by unplugging electrical connectors and hydraulic lines, then install the new ABS unit by reversing the removal steps. It is recommended to consult a repair manual specific to your vehicle for detailed instructions.
Bring to a shop that has an ABS scanner to determine problem
it could be abs break unit
I have the same truck and year and the same problem and was told that the abs sensor unit needs to be cleaned along with the calipers. I was told to remove the calipers and rotors and sensor unit and clean all of them with a wire brush or sandpaper and that dirt gets in there and gives a false reading causing the abs to activate. The unit is on the left front wheel
Follow the 2 brake lines that lead out of the master cylinder, they run to the ABS unit.
Faulty ABS unit .
Pull the ABS fuse located in the under hood fuse box. Pull the ABS fuse located in the under hood fuse box.
Find the ABS wheel sensor. Loosen the bolts that attach it to the suspension. Remove the bolts that hold the sensor to the wiring. Remove all other bolts. Remove the ABS sensor.
My dealer says the ABS modulator is bad. He is ordering this $1100 part and it should fix the problems. Fortunately it is under warrenty. Without the fix, the ABS will not work.
The ABS pump relay is intergrated into the EHCU (elecro-hydraulic control Unit) and it is not serviceable. If the ABS pump relay is defective, the entire control unit must be replaced.
Either one of the four ABS sensors went bad, or most likely your ABS computer failed and needs to be rebuilt.