Mitsubishi Eclipse. Technical Information Manual (1994) — part 69
ABS
INITIAL CHECK FUNCTION
The ECU always performs an initial check on the
ABS system with the on-board diagnostic function.
1. Initial Check Operation
(1) When the ignition key is placed in the ON posi-
tion, the power is supplied to the ABS-ECU,
and the ABS-ECU starts a diagnostic sequence.
During the diagnostic period, the ABS valve
relay stays in the “OFF” state and the warning
light continues to light.
(2) Then, the ABS-ECU forces the ABS valve relay
into the “ON” state and executes diagnostic test
mode of the ABS valve relay to detect an ON
or OFF failure.
(3) All the solenoid valves are caused to be ON
and OFF to make sure that the valves are not
sticking.
If it detects an error, it illuminates the warning light,
and disables the ABS system.
(4) If the engine starts and the ignition key is re-
turned to the “ON” position, the ABS-ECU power
supply is resumed, and initial checks in (1)
through (3) are performed again.
(5) When the initial checks are satisfactorily com-
pleted, the ABS becomes ready for operation.
NOTE
An operation check for the motor relay and the motor
is performed when the vehicle is put in motion after
starting the engine. This check is performed only
once whenever the ignition switch is turned “ON”.
START
Ignition key
ACC
ABS-ECU
power supply
.
ABS
warning light
ABS valve
relay
Solenoid ON
valve
OFF
ABS
FAIL-SAFE FUNCTION
Should a failure occur in the ABS system, the
ECU isolates the system to retain the vehicle’s ordi-
nary braking function, thus assuring a high measure
of safety.
l
If the ABS-ECU determines that the system
is defective as the result of diagnostic test mode,
DIAGNOSTIC FUNCTIONS
To facilitate inspection of the ABS system, the
ECU offers the following facilities:
l
Diagnostic trouble code output and erasure
l
Actuator test
All of the items described above can be checked
by the scan tool.
Scan Tool
ABS Interface
The scan tool function is entered by connecting
the scan tool to the data link connector. At this time,
it causes the ABS warning light to light, drives
the valve relay to interrupt control of the solenoid
valves in the HU, and restores the ordinary brak-
ing mode.
the vehicle must be stopped, and the ignition should
be OFF.
The ABS scan tool mode is entered when you select
the ABS system on the scan tool. In this mode,
diagnostic output, data list output and actuator test
functions are available. During an actuator test, how-
ever, the ABS warning light illuminates and anti-lock
control is inhibited to prevent ABS operation when
a brake is temporarily inactivated during the actuator
Scan tool
Wheel speeds of 0 km/h (0 mph), parked
mode entry
tion
condition
Check harness of scan tool connected to data
link connector of vehicle
ABS system selected by control switch of scan
tool (Specified serial data received)
NOTE
No communications with the ABS-ECU can be made by con-
necting the scan tool while the vehicle is in operation [wheel
speeds not 0 km/h (0 mph)].
ABS
Diagnostic Trouble Codes
Conditions detected as a result of diagnosis are
associated with a total of 14 codes including that
for normal state, and the codes are stored in the
volatile memory.
Even if the ignition key is placed in the “OFF”
tion, the contents of the memory are not cleared,
as the memory remains powered by a backup power
These codes are readable by connecting the scan
When the scan tool is not used, they are also
able with a voltmeter which deflects in a pattern
unique to each code.
1. Diagnostic items, diagnostic codes and detection condition
Detection
Code No. display
Inspection item
on Scan tool
Diagnostic content
tions
A B
Front right wheel speed sensor
Front left wheel speed sensor
Rear right wheel speed sensor
Open circuit or short in wire
x x
Rear left wheel speed sensor
Wheel speed sensor system
Abnormal output signal
X
21
G sensor
Broke wire in G sensor or OFF mal-
function
X
Stop light switch system
Open circuit or ON malfunction
X
41
Front left solenoid valve
No response to solenoid valve drive
42
Front right solenoid valve
signal
X
43
51
55
No fault code
displayed
Rear solenoid valve
Valve relay
Motor relay or Motor
ABS-ECU
(The system is in order)
Current value in both valves is differ-
ent when in same mode
X
Valve relay OFF failure
x x
Motor relay OFF failure and motor
drive failure
X
ABS-ECU internal failure (program
maze, etc)
Detection conditions
A: During system check immediately after staritng
B: During operation
DRIVE-CONTROL COMPONENTS ABS
NOTE
The ABS-ECU can detect only an open circuit from the moment the ECU power supply is ON.
The ABS-ECU lights the ABS warning light when it detects an open circuit, but it does not immediately store
the trouble code in memory and does not cause the system to shut down.
When an open circuit is detected, the trouble code is stored in memory and the system caused to shut down
when the vehicle starts and the wheel speed reaches 6 km/h (4 mph) (the first acceleration after the
has
been placed in the ON state).
Troubles other than an open circuit cannot be detected until the wheel speed reaches 6 km/h (4 mph). When
the ABS-ECU detects any of these troubles, it causes the system to shut down and simultaneously lights the
ABS warning light.
The shut down
time varies with the wheel speed as described below.
First start after engine start:
l
When the wheel speed is less than 10 km/h (6 mph), the system shuts down 60 seconds later.
l
When the wheel speed is 10 km/h (6 mph) or more, the system shuts down immediately.
Restart:
l
When the wheel speed is less than 20 km/h (12 mph), the system shuts down 60 seconds later.
l
When the wheel speed is 20 km/h (12 mph) or more, the system shuts down immediately.
When the ABS-ECU detects a wheel speed sensor error during ABS control, it causes the system
to come down and simultaneously lights the ABS warning light after ABS control.
The ABS-ECU takes more than 15 minutes from when it detects an error to when it determines that the fault
has occurred.
The ABS-ECU makes an initial check on the motor relay and motor when the wheel speed reaches 6 km/h
(4 mph) for the first time after engine start. If anything wrong is detected, it causes the system to shut down
and simultaneously lights the ABS warning light.
Нет комментариевНе стесняйтесь поделиться с нами вашим ценным мнением.
Текст