Mitsubishi 1989 Galant, Service Manual

Page: 1006 / 1273

ACTIVE-ELECTRONIC CONTROL SUSPENSION Troubleshooting
Operation
The front air-supply valves are switched ON
for air supply to the left and right strut air springs
during attitude control and during vehicle-height
justment upward.
Diagnostic
If there is damage or disconnection of the heavy-line
circuit, or a malfunction of an output transistor
within the ECU, the alarm light illuminates, and
Usually, and during air exhaust, these valves are
OFF (closed).
Note that a check valve is provided in these valves in
order to prevent reverse flow of the air.
control is as described in the table below.
Note that the malfunction-detection circuit is the
same for the rear air-supply valves.
Diagnostic No.
Attitude control
Damping force
control
Vehicle-height
control
HIGH
Switch acceptance
SPORT AUTO SOFT
51 Control stop Held at MEDIUM
Control stop
Not accept
Actuator compulsory activation
The front air-supply valves are activated by the
following.
Applicable operation
0 8 Vehicle herght upward adjustment
I
09 Rolling control (left turn)
Rolling control (right turn)
ECU terminal voltage {when connector is connected)
Terminal
No
Signal
T e r m i n a l
voltage
21 Front valve
activation signal
When the front air-supply valves are ON (open)
When the front are OFF (closed) o v
During fail-safe (for solenoid valve power source relay switch o v
Battery positive voltage
Checking the front air-supply valve activation circuit (with the connector disconnected)
T e r m i n a l C o n n e c t i o n d e s t i n a t i o n o r M
e a s u r e m e n t
No. measured part
Tester connection
Check condition Standard
21 Front air-supply valve 21 -ground
Constantly
Approx.
Troubleshooting hints (mechanical malfunctions)
Malfunction
mode
Malfunction probable cause Malfunction Note
Stuck in the cannot be supplied in because
l
The front vehicle-height will not increase.
OFF (closed) the valve
IS
stuck in the OFF (closed)
l
Insufficient control of rolling and braking dive
position
due to corrosion, freezing, etc
l
The front vehicle-height decreases after rolling
caused by penetration control.
Stuck in the Air supply cannot be stopped
ON (open)
The front vehicle-height increases and the body tilts
because the valve is stuck in the ON
to one side
(open) due to freezing,
etc. caused by penetratron.
Air leakage at Valve seat
IS
worn,
l
When left as is, the front increases. Diagnostic
the
l
The front vehicle-height downward adjustment
output
seat
frequency increases.
leakage
Wear, etc of the O-ring, etc.
l
When left as the front vehicle-height decreases.
Very slight leakages can-
to
l not be detected Such
atmosphere
Air is not accumulated in the high-pressure tank.
l
The compressor is activated too frequently.
leakage is detected a long
afterward by a decre-
ase of the vehicle height
TSB Revision