Honda Civic Service Manual page 633

ABS Control Unit
Main Control
The ABS control unit detects the wheel speed based on the wheel sensor signal it received, then it calculates the
vehicle speed based on the detected wheel speed. The control unit detects the vehicle speed during deceleration
based on the rate of deceleration.
The ABS control unit calculates the slip rate of each wheel and transmits the control signal to the modulator unit
solenoid valve when the slip rate is high.
The pressure reduction control has three modes: pressure reducing, pressure retaining, and pressure intensifying.
Self-diagnosis Function
1 . T h e A B S c o n t r o l u n i t i s e q u i p p e d w i t h a m a i n C P U a n d a s u b - C P U . E a c h C P U c h e c k s t h e o t h e r f o r p r o b l e m s .
2. The CPUS check the circuit of the system.
3 . T h e A B S c o n t r o l u n i t t u r n s o n t h e A B S i n d i c a t o r w h e n t h e u n i t d e t e c t s a p r o b l e m a n d t h e u n i t s t o p s t h e s y s t e m .
4. The self-diagnosis can be classified into these two categories:
. l n i t i a l d i a g n o s i s
. R e g u l a r d i a g n o s i s
On-board Diagnosis Function
The ABS can be diagnosed with the Honda PGM Tester.
The ALB Checker cannot be used with this system. For air bleeding and checking wheel sensor signals. use the Honda
PGM Tester. See the Honda PGM Tester user's manual for specific operating instructions.
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