Ford Expedition 2003 Workshop Manual page 17

2003 Expedition/Navigator Workshop Manual
Lift and support the vehicle off the ground until the front tires can be spun freely. Refer to
Section 100-02.
NOTE: The engine is required to be at idle during the following steps to supply the vacuum
required for the hublocks to engage and disengage.
Start engine and allow to idle.
Place the shift selector into 2H mode.
Spin the tires.
Are the hub locks engaged?
E2 CHECK FOR GROSS VACUUM LEAK
Set the heater control to FLOOR.
Check heat output at defroster vents.
Is the heater mode selector stuck at DEFROST?
E3 CHECK FOR VACUUM LEAK IN FRONT AXLE HUB LOCK SYSTEM
Disconnect the vacuum line at the IWE solenoid (located on the firewall behind the battery).
Connect the vacuum pump to the vacuum supply line.
Apply a vacuum of 20 inches of mercury to the hublock vacuum for 30 seconds.
Is a vacuum leak greater than 25 mm (1 in) Hg/minutes indicated?
E4 CHECK FOR VACUUM LEAK IN RIGHT FRONT AXLE HUBLOCK
Disconnect and plug the vacuum line at the RF hublock.
Apply a vacuum of 20 inches of mercury directly to RF hublock assembly.
Monitor the hublock vacuum for 30 seconds.
Does the RF hublock leak down at a rate less than 1 inHg/minute?
E5 CHECK FOR VACUUM LEAK IN LEFT FRONT AXLE HUBLOCK
Disconnect and plug the vacuum line at the LF hublock.
Apply a vacuum of 20 inches of mercury directly to the LF hublock.
Monitor the system vacuum for 30 seconds.
Does the LF hublock leak down at a rate less than 1 inHg/minute?
E6 CHECK FOR VACUUM LEAK IN VACUUM LINES
Connect the vacuum pump to the vacuum supply line. Cap off the vacuum delivery line at both
actuators.
Apply a vacuum of 20 inches of mercury to the hublock vacuum system.
Monitor the system vacuum for 30 seconds.
Is a vacuum leak greater than 1 inHg/minute indicated?
E7 CHECK FOR CORRECT FOUR-WHEEL DRIVE CONTROL MODULE OPERATION
Ignition OFF.
Disconnect all four-wheel drive control module connectors (C3184a and C3184b) and the
transfer case connector (C350).
Check for:
corrosion
pushed-out pins
Connect all four-wheel drive control module connectors (C3184a and C3184b) and the transfer
case connector (C350), and make sure that they seat correctly.
Operate the system and verify the concern is still present.
Is the concern still present?
PINPOINT TEST F: DTCS C1979/C1980 — IWE SOLENOID CIRCUIT FAILURE/IWE SOLENOID SHORT TO BATTERY
F1 CHECK CIRCUIT 605 (RD) FOR SHORT TO BATTERY
Disconnect: IWE Solenoid C1157.
Disconnect: Four Wheel Drive (4WD) Control Module C3184b.
Measure the voltage between IWE solenoid C1157 pin 2, circuit 605 (RD) harness
side and ground.
Is voltage present?
F2 CHECK CIRCUIT 605 (RD) FOR SHORT TO GROUND
Measure the resistance between IWE solenoid C1157 pin 2, circuit 605 (RD) harness
http://www.fordtechservice.dealerconnection.com/pubs/content/~WS3J/~MUS~LEN/20/S...
Test Step
Yes
GO to E2.
No
GO to Pinpoint Test D.
Yes
REPAIR or INSTALL a new vacuum supply hose or
vacuum reservoir as necessary. REFER to
00.
No
GO to E3.
Yes
GO to E4.
No
GO to E7.
Yes
GO to E5.
No
INSTALL a new hublock. REFER to
Yes
GO to E6.
No
INSTALL a new hublock. REFER to
Yes
REPAIR or INSTALL a new vacuum supply hose or
tube as necessary.
No
GO to E7.
Yes
INSTALL a new four-wheel drive control module.
No
The system is operating correctly at this time. Concern
may have been caused by a loose or corroded
connector.
Result / Action to Take
Yes
REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
No
IF DTC C1979, GO to F2 .
If DTC C1980, INSTALL a new four wheel drive (4WD) control
module. REFER to Four Wheel Drive (4WD) Control Module
this section. REPEAT the self-test.
Yes
Page 17 of 18
Section 412-
Section 205-03.
Section 205-03.
in
1/22/2010