Procedure III

For 4X4 lamps flashing with one or a combination of DTCs P1838, P1846, P1850, P1854, P1858, P1866 and P1867 stored in the GEM, perform the following repair procedure:

1. Verify that DTCs P1838, P1846, P1850, P1854, P1858, P1866 and/or P1867 are present in the GEM. Then clear all stored DTCs and cycle the ignition key (on-off-on). Monitor contact plate A, B, C, and D PIDs using an NGS Tester while the transfer case is in 4X4 AUTO and 4X4 LOW mode. Verify that the contact plate PIDs correspond to appropriate 4WD positions (4X4 AUTO - "COCC", 4X4 LOW - "0C0C" where "C" is Closed and "0" is Open).

2. Refer to the following Steps 2a, 2b, 2c for PID diagnostics:

a. (Upstream Check) If the contact plate PIDs DO NOT correspond to the set 4WD position, check for continuity (open or short) in the contact plate circuit (on the vehicle side) of the 1999 Explorer/Mountaineer Workshop Manual, Section 308-07A, per Pinpoint Tests B40-B54. Visually inspect all terminal pins, crimps, and connectors closely. If there are problems with the wiring, repair all wiring concerns as necessary and proceed to Step 4.

b. (Downstream Check) If the contact plate PIDs DO NOT correspond to the set 4WD position and the wiring/connector checks out OK, measure the resistance on the transfer case shift motor contact plates while the 4WD is in 4X4 AUTO and 4X4 LOW position. Refer to Figure 1 for the Connector C201 pin-out chart to measure the transfer case shift motor contact plate resistance as follows:

^ To measure the contact plate "A" resistance, measure between C201 - Circuit 771 (P/Y) and C201-10 Circuit 762 (Y/W).

^ For contact plate "B" resistance, measure between 0201-1 Circuit 770 (W) and C201-10 Circuit 762 (Y/W).

^ For contact plate "C" resistance, measure between C201-9 Circuit 764 (BR/W) and C201-10 Circuit 762 (Y/W).

^ For contact plate "D" resistance, measure between C201 -13 Circuit 763 (O/W) and C201-10 Circuit 762 (Y/W).

Resistance less than 1.25 Ohms is considered "Closed". Resistance greater than 5100 Ohms is considered "Open". If the resistance on any one of the contact plates is between 1.25 and 5100 Ohms, replace the shift motor. Also, if the resistance check on the shift motor contact plate A, B, C, and D DO NOT correspond to "COCC" in 4X4 AUTO and "OCOC" in 4X4 LOW, replace the shift motor with a new Transfer Case Shift Motor (XL2Z-7G360-AA). Proceed to Step 3.

c. If the contact plate PIDs DO correspond to the set 4X4 position, replace the shift motor with a new shift motor. Proceed to Step 3.

3. (ON Left Hand Drive Vehicles ONLY! NOT applicable to Right Hand Drive Vehicles) Install a new 4X4 Jumper Wiring Harness (XL2Z-7A786-AC) that goes from underneath the driver seat to Connector 0201 on the transfer case. Proceed to Step 4.

4. Test drive to see if the condition returns. Pull DTCs from the GEM module and confirm that no DTCs exist. Clear DTCs from GEM module (even if there are no DTCs available) and cycle ignition.