1995 Opel Vectra ABS

KURT LORENTZEN

MEMBER
1995 OPEL VECTRA
4 CYL
2WD
MANUAL
300,000 MILES

The ABBS-lamp is continually lit. I have been told by an Opel-man that the ground connection, a rod going into the unit (thick brown wire mounted on the front of the ABS unit) is loose and therefore gone. He told me that I have to exchange the entire unit.
Question1: Can I disassemble the part of the the unit in which the ground-rod goes in? As far as I can read from the wiring diagram, the ground rod connects to one end of some motor(?).
Question 2:I have been told that the electronics counts the number of pulses it receives from each impuls ring at the weels. I cannot believe it does so, 'cause them it would have to keep track of the revolutions of the wheels, too, and I cannot see how it would do that. Can I have a comment on that, please.
The ABS unit is a Bosch.
Yours, Kurt Lorentzen

1 Reply

DAVE H

MECHANIC
13,383 POSTS

ANTI-LOCK BRAKE SYSTEM (ABS)
During normal driving and braking operation, ABS performs by automatically modulating braking pressure during an emergency stop to prevent wheel lock-up. Each Wheel Speed Sensor (sensor) constantly sends an AC signal to Anti-lock Brake Control Module (ABCM). This information is translated to wheel rotation speed. When ABCM determines that wheel lock-up is about to occur, it activates electromagnetic Isolation (ISO) Solenoid Valve (dump valve), located inside Hydraulic Control Unit (HCU), to increase or decrease hydraulic pressure to each wheel. HCU is not serviceable, and must be replaced as an assembly.