Diagnostic Procedure 3
DIAGNOSTIC PROCEDURE 3SYMPTOM: Abnormalities when starting engine
NOTE:
When engine is started, the flow control valve is energized for approx. 10 seconds changing the vehicle height gradually. After this period, the flow control valve is de-energized. The vehicle height is gradually controlled to a level according to the signals from the G sensor and vehicle height sensor.
Accordingly, possible troubles when starting engine are as follows:
1) Abrupt rise in vehicle height (malfunctioning flow control valve),
2) Tilting of vehicle (difference in outputs of G sensors), and
3) Abnormal control signal from control unit.
1) ABRUPT RISE IN VEHICLE HEIGHT
NOTE:
If the flow control valve is seized in the de-energized position, the vehicle may raise immediately after starting the engine. This indicates that the control level of the pressure control valve is set at 5,002 kPa (51 kg/cm2, 725 psi). For about 10 seconds after starting the engine, a sudden change in the supply pressure also causes the control pressure to be increased abruptly to 5,002 kPa (51 kg/cm2, 725 psi). Similar behavior may occur if a disconnection occurs in the flow control valve circuit. In this case, however, the fail-safe function prevents the trouble from occurring.
2) TILTING OF VEHICLE
a) Tilting in fore and aft direction
NOTE:
If front and rear G sensors or lateral G sensors outputs are diflerent, the vehicle position may tilt approx. 10 seconds after starting engine. After some time, the vehicle may recover its level position. This is because, if the outputs of G sensors are not equal, the difference in output causes a change in vehicle position. The amount of control is increased gradually to bring the vehicle to the normal level.
b) Tilting in lateral direction