Suzuki sq-416-420-625 Service Manual page 504

7E-2 DIFFERENTIAL (FRONT)
4WD CONTROL SYSTEM
When the 4WD switch is turned ON by shifting the transfer shift lever, ECM (PCM) (G16 and J20 engine models)
or 4WD controller (H25 engine model) actuates (energizes) the air pump assembly. Then positive pressure is sent
from the air pump assembly to the actuator installed to the differential case and causes the axle lock clutch and
the free axle hub in the differential case to be engaged, resulting in the 4WD mode. Only when running in the 4WD
mode, front axles are joined to differential case, and they become free when 2WD mode is used (or when transfer
shift lever is shifted to N position), thereby reducing the power loss.
1. 4WD switch
2. Transfer
3. Blank
4. Blank 10. Free axle hub
5. ECM or PCM 11. 4WD indicator lamp
6. Glove box
7. Air pump assembly
8. Actuator
9. Axle lock clutch