Procedure II

For 4X4 lamps flashing with one or a combination of DTCs P1836, P1837, P1874, and P1875 stored in the GEM, perform following repair procedure:

1. Verify that DTCs P1836, P1837, P1874, and/or P1875 are present in the GEM. Then clear all stored DTCs and cycle the ignition key (on-off-on). Place the 4WD mode switch in 4X4 AUTO position. Monitor TRA_FSP and TRA_RSP Parameter Identification Displays (PIDs) using an NGS Tester at 80 km/h (50 mph) steady state driving. Verify that the two PIDs, TRA_FSP and TRA_RSP, are within 2-3 km/h (1-2 mph) of one another during steady state driving.

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

a. (Upstream Check) If the two PIDs are NOT within 2-3 km/h (1-2 mph), check for continuity (open or short) in the speed sensor circuit on the vehicle side of Connector C201, 1999 Explorer/Mountaineer Workshop Manual, Section 308-07A, per Pinpoint Tests A33-A38. 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 two PIDs are NOT within 2-3 km/h (1-2 mph) and the wiring/connector checks out OK, measure the resistance on the front and rear speed sensors (on the transfer case side of Connector C201). Refer to Figure 1 for the Connector C201 pin-out chart to measure the speed sensor resistance as follows:

^ For the front speed sensor, measure between C201-4 Circuit 236 (BK/LG) and C201-8 Circuit 359 (GY/R).

^ For the rear speed sensor, measure between C201-2 Circuit 772 (LB) and C201-6 Circuit 359 (GY/R).

Replace all speed sensors with resistance less than 1,000,000 (1.0 Mega) Ohm. Service part numbers for the new speed sensors are: XL2Z-7F293-BA (front speed sensor) and XL2Z-7F293-AA (rear speed sensor). Proceed to Step 3.

c. If the two PIDs are within 2-3 km/h (1-2 mph), replace only the appropriate speed sensor per stored DTC in GEM. For vehicles with P1836 DTC, install a new Front Speed Sensor (XL2Z-7F293-BA). For vehicles with P1837 DTC, install a new Rear Speed Sensor (XL2Z-7F293-AA). 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 that goes from underneath the driver seat to Connector C201 on the transfer case. The service part number for the new 4X4 Jumper Wiring Harness is XL2Z-7A786-AC. Proceed to Step 4.

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