C10
CHECK THE FRONT DRIVESHAFT DISENGAGEMENT
NOTE:
When 4WD is disengaged, the front driveshaft may spin due to viscous drag in the
transfer case, especially if cold. If this occurs, the front driveline can easily be stopped.
Disengage 4WD. Only the rear driveshaft should spin.
Does only the rear driveshaft spin?
Yes
GO to
C11
.
No
GO to
Pinpoint Test A
.
C11
CHECK THE FRONT AXLE AND THE FRONT DRIVESHAFT DISENGAGEMENT
Trigger the GEM active commands AXLE ENGG to OFF and AXLE DSCN to ON.
Spin one front tire. The other front tire should not spin.
Is the axle disconnect working properly?
Yes
The 4WD system is working properly.
No
GO to
C12
.
C12
CHECK 4WD AND 2WD VACUUM HUB SOLENOID CIRCUITS — MONITOR THE GEM PIDS 4WDSOL AND 2WDSOL
Monitor the GEM PIDs 4WDSOL and 2WDSOL while triggering the GEM active commands
AXLE ENGG and AXLE DSCN to ON.
Does the GEM PID 4WDSOL indicate ON--- and the GEM PID 2WDSOL indicate ON---?
Yes
GO to
C13
.
No
If PID displays ON-B-, GO to
C14
.
C13
CHECK 4WD AND 2WD VACUUM SOLENOIDS — MONITOR THE GEM PIDS 4WDSOL AND 2WDSOL
Monitor the GEM PIDs 4WDSOL and 2WDSOL while triggering the GEM active commands
AXLE ENGG and AXLE DSCN to OFF.
Does the GEM PID 4WDSOL indicate OFF--- and GEM PID 2WDSOL indicate OFF---?
Yes
GO to
C23
.
No
If the GEM PIDs display OFFO-G, GO to
C16
.
C14
CHECK CIRCUITS 145 (GY/BK) AND 605 (R) FOR SHORT TO POWER
Page 54 of 74
1998 F-150/250 Workshop Manual
1/11/2011
http://www.fordtechservice.dealerconnection.com/pubs/con...