Ford Expedition 2003 Workshop Manual page 13

2003 Expedition/Navigator Workshop Manual
connector (C350).
Check for:
corrosion
pushed-out pins
Connect all 4WD control module connectors and the transfer case connector and make sure
they seat correctly.
Operate the system and verify the concern is still present.
Is the concern still present?
PINPOINT TEST D: THE VEHICLE DOES NOT SHIFT BETWEEN AUTO/4WD HIGH AND 4WD LOW MODES CORRECTLY
D1 REVIEW THE FOUR-WHEEL DRIVE (4WD) CONTROL DIAGNOSTIC TROUBLE CODES
Connect the scan tool.
CARRY OUT the 4WD control module self-test.
Are any DTCs retrieved?
D2 CHECK THE DIGITAL TRANSMISSION RANGE (TR) SENSOR
CARRY OUT the instrument cluster module self-test.
Are any DTCs retrieved?
D3 CHECK BRAKE PEDAL SWITCH PID
Monitor the ABS module brake input switch status PID.
Step on the brake pedal.
Does the brake input switch status PID indicate active?
D4 CHECK WHEEL SPEED SENSOR INPUTS
Monitor the ABS module wheel speed sensor inputs.
Do the wheel speed sensor inputs indicate 0 kph (0 mph)?
D5 CHECK THE MODE SELECT SWITCH (MSS)—MONITOR THE 4WD CONTROL
MODULE PID 4WD_SW
Ignition ON.
Monitor the 4WD control module PID: 4WD_SW while selecting each of the positions on
the mode select switch (MSS).
Do the 4WD control module PID values agree with the MSS positions?
D6 CHECK THE MSS — ALL POSITIONS
Disconnect: MSS C284.
Measure the resistance between MSS terminals 2 and 3 while rotating the switch through
all positions. Refer to the following chart:
MSS Position Resistance
A4WD 264.33 - 269.67
4WD HIGH 128.7 - 131.3
4WD LOW 61.38 - 62.62
2WD HIGH 616.9 - 623.1
Are all the resistances within the specified values?
D7 CHECK CIRCUITS 682 (DB) AND 780 (DB) FOR A SHORT TO POWER
Disconnect: 4WD Control Module Connector C3184b.
Ignition ON.
Measure the voltage between 4WD control module connector C3184b pin 10, circuit 682
(DB) and ground.
http://www.fordtechservice.dealerconnection.com/pubs/content/~WS3J/~MUS~LEN/20/S...
Test Step
INSTALL a new 4WD control module. CLEAR the
DTCs. REPEAT the self-test.
No
The system is operating correctly at this time. Concern
may have been caused by a loose or corroded
connector. CLEAR the DTCs. REPEAT the self-test.
Result / Action to Take
Yes
If DTC B2105, B2106, C1979 or C1980 are retrieved,
Pinpoint Test B. If DTC P1812 is retrieved, GO to
P1849, P1853, P1857, P1861 or P1867 are retrieved, GO to
D10 . If DTC U1900, U1950, U2023, U2306 or U2226 is
retrieved, REFER to Section 418-00. For all other DTCs, GO
to D2 .
No
GO to D2.
Yes
Section 413-01.
No
GO to D3.
Yes
GO to D4.
No
REFER to Section 206-09.
Yes
GO to D5.
No
REFER to Section 206-09.
Yes
GO to D7.
No
GO to D6.
Yes
GO to D7.
No
INSTALL a new MSS. REFER to Mode Select Switch (MSS)
in this section. CLEAR the DTCs. REPEAT the self-test.
Yes
REPAIR the affected circuit(s). CLEAR the DTCs. REPEAT
the self-test.
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GO to
D5 . If DTC
1/22/2010