Abs Components General Troubleshooting Information - Honda 2002 Accord Manual

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ABS
General Troubleshooting Information
ABS Indicator
• If the system is OK, the A B S indicator goes off t w o
seconds after t u r n i n g the ignition switch ON (II)
w i t h o u t starting the engine, and then comes on again
and goes off 2 seconds after starting the engine. This
occurs because the ABS control unit is turned on by
the IG2 p o w e r source.
• The ABS indicator comes on when the ABS control
unit detects a p r o b l e m in the system. However, even
t h o u g h the system is operating properly, the ABS
indicator w i l l c o m e on, under the following
conditions:
- Only drive wheels rotate
- One drive wheel is stuck
- Vehicle spins
- ABS continues to operate for a long time
- Signal disturbance
To determine the actual cause of the problem, question
the customer about the problem, taking the above-listed
conditions into consideration.
• When a p r o b l e m is detected and the ABS indicator
comes o n , there are cases w h e n the indicator stays
on until the ignition switch is turned OFF, and cases
w h e n the indicator light goes off automatically w h e n
the system returns to n o r m a l . For DTCs 61 and 62, the
indicator goes off automatically when the system
returns to n o r m a l . For all other codes, the indicator
stays on until the ignition switch is turned OFF.
• For DTCs 12, 14, 16, 18, 2 1 , 22, 23, 24, 51, 52 and 53,
the ABS indicator goes off w h e n the vehicle is driven
again and the system is OK after the ignition switch is
turned f r o m OFF to ON (II). However, if the DTC is
cleared, the CPU resets and the indicator goes off
right after the engine is started if the system is OK.
Diagnostic Trouble Code (DTC)
Self-diagnosis
• Self-diagnosis can be classified into 2 categories:
- Initial diagnosis:
Done right after the engine starts and until the ABS
indicator goes off.
- Regular diagnosis:
Done right after the initial diagnosis until the ignition
switch is turned OFF.
• W h e n a problem is detected by self-diagnosis, the
system:
- Turns the fail-safe relay OFF
- Turns the solenoid valve OFF
- Turns the pump motor OFF
- Turns the ABS indicator ON
Kickback
The m o t o r operates w h e n the ABS is functioning, and
the fluid in the reservoir is forced out to the master
cylinder, causing kickback at the brake pedal.
Pump M o t o r
• The p u m p motor operates when the ABS is
functioning.
• The ABS control unit checks the p u m p motor
operation during initial diagnosis w h e n the vehicle is
started. You may hear the motor operate at this t i m e ,
but it is normal.
Brake Fluid Replacement/Air Bleeding
Brake fluid replacement and air bleeding procedures
are the same as for vehicles without ABS.
To ease bleeding, start w i t h the front wheels.
• If the CPU cannot be activated or the CPU fails, the
ABS indicator comes o n , but the DTC is not
memorized.
• The m e m o r y can hold any number of DTCs. However,
when the same DTC is detected more than once, the
later one is written over the old one.
Therefore, w h e n the same problem is detected
repeatedly, it is memorized as one DTC.
• The DTCs are indicated in the order of ascending
number, not in the order they occur.
• The DTCs are memorized in the EEPROM (non-
volatile m e m o r y ) . Therefore, the memorized DTCs
cannot be canceled by disconnecting the battery.
Do the specified procedures to clear the DTCs.
(cont'd)
19-37