ANTI-LOCK BRAKING SYSTEM
Fault finding - Dealing with commands
38C
38C - 48V2 MR-372-J84-38C000$792_eng.mif
BOSCH ABS 8.0
Vdiag No.: 0C, 0D, 0E, 0FANTI-LOCK BRAKING SYSTEM
Fault finding - Dealing with commands
CLEARING
RZ001:Fault memory.
This command is used for clearing the computer's stored faults.
ACTIVATION
AC003:
AC004:
AC005:
AC006:Front left-hand wheel solenoid valves.
Front right-hand wheel solenoid valves.
Rear left-hand wheel solenoid valves.
Rear right-hand wheel solenoid valves.
These commands permit a check on the hydraulics of each wheel.
Position the vehicle on a 2-post lift so that the free rotation of the wheels can be checked.
Keep the brake pedal depressed enough to prevent the wheel being tested from being turned by hand (do not brake
so hard that the anti-lock function operates).
Select and confirm the command for the wheel in question (e.g. Left-hand front wheel solenoid valve, etc.).
Turn the wheel concerned by hand: 5 braking/releasing cycles should be detected.
AC013:Wheel speed sensor supply test.
This command is used to check that voltage pulses of approximately 12 V are detected on the faulty
sensor by a multimeter at the terminals of the sensor connector on the computer side.
You must use command AC013 once only.
AC016:Pump motor test.
This command is used to test the pump motor control circuit.
Select command AC016 Pump Motor Test.
The motor must run for 5 seconds.
AC195:Vehicle speed signal.
This command serves to generate a speed other than 0 mph at the computer's vehicle speed wire output
(Track 23) for users of that signal (xenon bulbs, radio, sunroof).
Note:
This command has no visible effect on the dashboard speedometer needle.
–Xenon headlights: Switch on the dipped headlights and run command AC195. Check for slight
variation in the height of the headlight beam while the command is running (the height of the beam is
adjusted to improve visibility according to vehicle speed).
–Radio: Turn on the radio and make sure that the Adjust volume as a function of speed function is
active. Run command AC195. Check that the volume of the sound increases and then decreases
while the command is running.
–Sunroof: This command has no visible effect on the sunroof. This command changes the activation
threshold of the anti-pinch system (the pressure exerted by the sunroof varies with vehicle speed due
to aerodynamic factors).
AC196:Request to switch on hazard warning lights.
This command sends the UCH a request to switch on the hazard warning lights to test their operation
during emergency braking (depending on UCH configuration).
ABS 8.0X84 4.0
MR-372-J84-38C000$792_eng.mif
