Honda 2004 Odyssey Service Manual page 1282

General Troubleshooting Information
ABS/TCS Indicators
• If the system is OK, the ABS indicator goes off once
after turning the ignition switch ON (II) without
starting the engine, and then comes on again and
goes off several seconds later after starting the
engine. This occurs because the ABS/TCS control unit
is turned on by the IG2 power source.
• The TCS or ABS indicator comes on when the ABS/
TCS control unit detects a problem in the system.
However, even though the system is operating
properly, the TCS or ABS indicator will come on,
under the following conditions:
• For ABS or TCS Indicator:
– Only drive wheels rotate
– One drive wheel is stuck
– The vehicle goes into a spin
– The ABS continues to operate for a long time
– The vehicle is subjected to an electrical signal
disturbance
• For TCS Indicator:
– The TCS operated when the front brake pad
temperature rises excessively
– The TCS switch is OFF
– One or more of these components are faulty:
Heated oxygen sensor, Manifold absolute pressure
sensor, Crankshaft position sensor, Engine coolant
temperature sensor, Throttle position sensor, Top
dead center sensor 1, Top dead center sensor 2,
Intake air temperature sensor, Exhaust gas
recirculation, Barometric pressure sensor, Idle air
control valve, VTEC pressure switch, Knock sensor,
Fuel supply system, Automatic transaxle, Misfire
detection system of the PGM-FI system
To determine the actual cause of the problem, question
the customer about the problem, taking the above-
listed conditions into consideration:
• When a problem is detected and the ABS or TCS
indicator comes on, there are cases when the
indicator stays on until the ignition switch is turned
OFF, and cases when the indicator goes off
automatically when the system returns to normal. For
ABS DTCs 61 and 62, the indicator goes off
automatically when the system returns to normal. For
all other codes, the indicator stays on until the
ignition switch is turned OFF.
• For ABS DTCs 12, 14, 16, 18, 21, 22, 23, 24, 51, 52 and
53, the ABS indicator goes off when the vehicle is
driven again and the system is OK after the ignition
switch is turned from 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.
• The ABS is not operational when the ABS indicator is
ON; the TCS is not operational when the TCS
indicator is ON.
• When the ABS and TCS indicators are both ON,
troubleshoot the ABS first.
• When the TCS indicator and MIL are both ON,
troubleshoot the PGM-FI system first.
Diagnostic Trouble Code (DTC)
• The memory can hold any number of DTCs. However,
when the same DTC is detected more than once, the
more recent DTC is written over the earlier one.
Therefore, when the same problem is detected
repeatedly it is memorized as a single DTC.
• The DTCs are indicated in ascending number order,
not in the order that they occur.
• The DTCs are memorized in the EEPROM (non-
volatile memory). Therefore, the memorized DTCs
cannot be canceled by disconnecting the battery. Do
the specified procedures to clear the DTCs.
Self-diagnosis
• Self-diagnosis can be classified into two categories:
– Initial diagnosis: Done right after the engine starts
and until the ABS or TCS indicator goes off
– Regular diagnosis: Done right after the initial
diagnosis until the ignition switch is turned OFF
• When a problem is detected by self-diagnosis, the
ABS/TCS control unit shifts to fail-safe mode.
Kickback
The pump motor operates when the ABS is functioning,
and the fluid in the reservoir is forced out to the master
cylinder, causing kickback at the brake pedal.
Pump Motor
• The pump motor operates when the ABS is
functioning.
• The ABS/TCS control unit checks the pump motor
operation during initial diagnosis when the vehicle is
started. You may hear the motor operate at this time,
but it is normal.
Brake Fluid Replacement/Air Bleeding
Brake fluid replacement and air bleeding procedures
are identical to the procedures used on vehicles not
equipped with ABS/TCS. To ease bleeding, start with
the front wheels.
(cont'd)
19-81