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Ford F-150 1998 Workshop Manual
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Ford F-150 1998 Workshop Manual

Transfer case—esof
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1998 F-150/250 Workshop Manual
SECTION 308-07A: Transfer Case — General Information
DIAGNOSIS AND TESTING
Transfer Case—ESOF
Refer to Wiring Diagrams Cell 34, Electric Shift Control for schematic and connector information.
Refer to Wiring Diagrams Cell 20, Starting System for schematic and connector information.
Refer to Wiring Diagrams Cell 59, Generic Electronic Module for schematic and connector information.
Special Tool(s)
73 Digital Multimeter or equivalent
105-R0051
New Generation STAR (NGS) Tester or equivalent
418-F048 (007-00500)
Vacuum Pump or equivalent
416-D001 (D83L-7059-A)
Electrical Shift on the Fly (ESOF) Vacuum Schematic
4WD Tables
Table 1 — 4WD Mode Switch Input Resistances
http://www.fordtechservice.dealerconnection.com/pubs/con...
Page 1 of 74
1998 F-150/250 Workshop Manual
Procedure revision date: 12/04/2002
1/11/2011

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Summary of Contents for Ford F-150 1998

  • Page 1 1998 F-150/250 Workshop Manual Page 1 of 74 SECTION 308-07A: Transfer Case — General Information 1998 F-150/250 Workshop Manual DIAGNOSIS AND TESTING Procedure revision date: 12/04/2002 Transfer Case—ESOF Refer to Wiring Diagrams Cell 34, Electric Shift Control for schematic and connector information. Refer to Wiring Diagrams Cell 20, Starting System for schematic and connector information.
  • Page 2 1998 F-150/250 Workshop Manual Page 2 of 74 Mode Switch Position Resistance (Ohms) 2-Wheel Drive 4100-3700 4WD HIGH 1050-1150 4WD LOW 380-340 Table 2 — Transfer Case Shift Relays Outputs HI-to-LO LO-to-HI Mode GROUND BATTERY 4 HIGH to 4 LOW BATTERY GROUND 4 LOW to 4 HIGH GROUND GROUND Brake Motor...
  • Page 3 1998 F-150/250 Workshop Manual Page 3 of 74 GEM Diagnostic Trouble Code (DTC) Index Description Caused By Action B1302 Accessory Delay Relay Coil Open or Short to Ground (Only REFER to Section 501-11. Set if Battery Saver Relay Has No Faults) B1304 Accessory Delay Relay Coil Short to Power REFER to Section...
  • Page 4 1998 F-150/250 Workshop Manual Page 4 of 74 P1810 4-Wheel Drive LO Indicator Short to Power GO to Pinpoint Test P1812 4-Wheel Drive Mode Select Switch Open or Short to Power GO to Symptom Chart. P1815 4-Wheel Drive Mode Select Switch Circuit Short to Ground GO to Symptom Chart.
  • Page 5 1998 F-150/250 Workshop Manual Page 5 of 74 PARK_SW Headlamp Control Input Switch ON, OFF PLATE_A Transfer Case Contact Plate Switch A OPEN, CLOSED PLATE_B Transfer Case Contact Plate Switch B OPEN, CLOSED PLATE_C Transfer Case Contact Plate Switch C OPEN, CLOSED PLATE_D Transfer Case Contact Plate Switch D OPEN, CLOSED...
  • Page 6 1998 F-150/250 Workshop Manual Page 6 of 74 Transfer case mechanism. Digital transmission range (TR) sensor. Circuitry. The Front Axle Is Not Engaging Properly (Transfer Case Motor Movement OK) 4x4 solenoid. GO to Pinpoint 4x2 solenoid. Test Vacuum motor. Circuitry. Vacuum lines.
  • Page 7 1998 F-150/250 Workshop Manual Page 7 of 74 REPLACE the fuse(s). CLEAR the DTCs. TEST the system for normal operation. If the fuse(s) fail again, CHECK for a short to ground. REPAIR as necessary. A3 CHECK CIRCUIT 1052 (T/BK) FOR VOLTAGE Fuse Junction Panel C243 Measure the voltage between fuse junction panel C243-11, circuit 1052 (T/BK), and ground.
  • Page 8 1998 F-150/250 Workshop Manual Page 8 of 74 If DTC B1342, REPLACE the GEM; REFER to Section 419-10. CLEAR the DTCs. TEST the system for normal operation. If DTC P1804, GO to Pinpoint Test If DTC P1806, GO to Pinpoint Test If DTC P1808, GO to Pinpoint Test If DTC P1810, GO to...
  • Page 9 1998 F-150/250 Workshop Manual Page 9 of 74 Monitor the GEM PID 4WDSGEM. Place the mode switch in the 2H position. Does the GEM PID indicate 2WD? GO to A9. GO to A11. A9 CHECK THE 4WD MODE SWITCH — MONITOR THE GEM PID 4WDSGEM (4H) Place the mode switch in the 4H position.
  • Page 10 1998 F-150/250 Workshop Manual Page 10 of 74 Mode Switch C230 Place the mode switch in the 2H position. Measure the resistance between the mode switch terminal 2 and terminal 3. Is the resistance between 3700 and 4100 ohms? GO to A12. REPLACE the mode switch;...
  • Page 11 1998 F-150/250 Workshop Manual Page 11 of 74 REPLACE the mode switch; REFER to Section 308-07B. CLEAR the DTCs. TEST the system for normal operation. A13 CHECK THE 4WD MODE SWITCH — 4L Place the mode switch in the 4L position. Measure the resistance between the mode switch terminals 2 and 3.
  • Page 12 1998 F-150/250 Workshop Manual Page 12 of 74 Is the resistance greater than 10,000 ohms? GO to A16. REPAIR circuit 780 (DB). CLEAR the DTCs. TEST the system for normal operation. A16 CHECK CIRCUIT 780 (DB) FOR SHORT TO POWER Measure the voltage between GEM C241-8, circuit 780 (DB), and ground.
  • Page 13 1998 F-150/250 Workshop Manual Page 13 of 74 REPLACE circuit 682 (DB). CLEAR the DTCs. TEST the system for normal operation. A18 CHECK CIRCUIT 682 (DB) FOR SHORT TO GROUND Multi-Function Switch C259 Measure the resistance between mode switch C230-2, circuit 682 (DB), and ground. Is the resistance greater than 10,000 ohms? GO to A19.
  • Page 14 1998 F-150/250 Workshop Manual Page 14 of 74 Is the axle disconnect working properly? EXIT the active command mode; GO to GO to Pinpoint Test A21 CHECK THE FRONT DRIVESHAFT ENGAGEMENT Place the mode switch in the 4H position. Verify the front and rear driveshafts both spin. Is the transfer case locking the front driveshaft to the rear driveshaft? GO to A22.
  • Page 15 1998 F-150/250 Workshop Manual Page 15 of 74 A24 CHECK THE TRANSFER CASE SHIFT RELAYS COIL ACTIVATION — MONITOR THE GEM PIDS MTR_CCW AND MTR_CW Monitor the GEM PIDs MTR_CCW and MTR_CW while triggering the GEM active command CW/CCW ON. Do the GEM PIDs MTR_CCW and MTR_CW indicate ON---? GO to A25.
  • Page 16 1998 F-150/250 Workshop Manual Page 16 of 74 Is the resistance less than 5 ohms? GO to A28. REPAIR circuit 781 (O/LB). CLEAR the DTCs. TEST the system for normal operation. A28 CHECK CIRCUIT 782 (BR/W) FOR OPEN Measure the resistance between transfer case shift relays C221-8, circuit 782 (BR/W), and GEM C241-16, circuit 782 (BR/W).
  • Page 17 1998 F-150/250 Workshop Manual Page 17 of 74 GEM C241 Measure the voltage between transfer case shift relays C221-8, circuit 782 (BR/W), and ground. Is any voltage indicated? REPAIR circuit 782 (BR/W). CLEAR the DTCs. TEST the system for normal operation. GO to A31.
  • Page 18 1998 F-150/250 Workshop Manual Page 18 of 74 A33 CHECK THE VOLTAGE TO THE ELECTRIC SHIFT MOTOR — MOTOR ON Transfer Case Assembly C201 Trigger the GEM active command CW/CCW to ON. Measure the voltage between transfer case assembly C201-14, circuit 778 (O), and ground; and between transfer case assembly C201-15, circuit 777 (Y), and ground.
  • Page 19 1998 F-150/250 Workshop Manual Page 19 of 74 Trigger the GEM active command CW/CCW to OFF. Measure the voltage between transfer case assembly C201-14, circuit 778 (O), and ground; and between transfer case assembly C201-15, circuit 777 (Y), and ground. Are the voltages greater than 10 volts? GO to A36.
  • Page 20 1998 F-150/250 Workshop Manual Page 20 of 74 Are the resistances less than 5 ohms? RECONNECT the transfer case assembly. GO to GO to A40. A38 CHECK CIRCUIT 777 (Y) FOR OPEN Measure the resistance between transfer case shift relays C221-7, circuit 777 (Y), and transfer case assembly C201-15, circuit 777 (Y).
  • Page 21 1998 F-150/250 Workshop Manual Page 21 of 74 Measure the resistance between transfer case shift relays C221-1, circuit 57 (BK), and ground. Is the resistance less than 5 ohms? REPLACE the transfer case shift relays. CLEAR the DTCs. TEST the system for normal operation.
  • Page 22 1998 F-150/250 Workshop Manual Page 22 of 74 REPAIR the transfer case (7A195) or shift motor assembly; REFER to Section 308-07B. CLEAR the DTCs. TEST the system for normal operation. GO to A42. A42 MONITOR THE GEM PID PLATE_A FOR OPEN Transfer Case Assembly C201 Trigger the GEM active command PLATE POWER to ON.
  • Page 23 1998 F-150/250 Workshop Manual Page 23 of 74 GEM C241 Measure the resistance between transfer case assembly C201-5, circuit 771 (P/Y), and ground. Is the resistance greater than 10,000 ohms? REPLACE the GEM; REFER to Section 419-10. CLEAR the DTCs. TEST the system for normal operation.
  • Page 24 1998 F-150/250 Workshop Manual Page 24 of 74 Is any voltage indicated? REPAIR circuit 771 (P/Y). CLEAR the DTCs. CYCLE the ignition OFF then ON. TEST the system for normal operation. GO to A47. A47 CHECK CIRCUIT 762 (Y/W) FOR SHORT TO POWER Measure the voltage between GEM C241-12, circuit 762 (Y/W), and ground.
  • Page 25 1998 F-150/250 Workshop Manual Page 25 of 74 GO to A51. GO to A50. A50 CHECK THE CIRCUIT 770 (W) TO THE CONTACT PLATE SWITCH B — MONITOR THE GEM PID PLATE_B Connect a jumper wire between transfer case assembly C201-10, circuit 762 (Y/W), and C201-1, circuit 770 (W).
  • Page 26 1998 F-150/250 Workshop Manual Page 26 of 74 Is the resistance less than 5 ohms? GO to A53. REPAIR circuit 770 (W). CLEAR the DTCs. CYCLE the ignition OFF then ON. TEST the system for normal operation. A53 CHECK CIRCUIT 770 (W) FOR SHORT TO POWER Measure the voltage between transfer case assembly C201-1, circuit 770 (W), and ground.
  • Page 27 1998 F-150/250 Workshop Manual Page 27 of 74 Monitor the GEM PID PLATE_C. Does the GEM PID PLATE_C indicate CLOSED? REMOVE the jumper wire; GO to GO to A57. A56 CHECK CIRCUIT 764 (BR/W) FOR SHORT TO GROUND GEM C241 Measure the resistance between transfer case assembly C201-9, circuit 764 (BR/W), and ground.
  • Page 28 1998 F-150/250 Workshop Manual Page 28 of 74 GO to A58. REPAIR circuit 764 (BR/W). CLEAR the DTCs. TEST the system for normal operation. A58 CHECK CIRCUIT 764 (BR/W) FOR SHORT TO POWER Measure the voltage between transfer case assembly C201-9, circuit 764 (BR/W), and ground.
  • Page 29 1998 F-150/250 Workshop Manual Page 29 of 74 GEM C241 Measure the resistance between transfer case assembly C201-13, circuit 763 (O/W), and ground. Is the resistance greater than 10,000 ohms? REPLACE the GEM; REFER to Section 419-10. CLEAR the DTCs. TEST the system for normal operation.
  • Page 30 1998 F-150/250 Workshop Manual Page 30 of 74 REPAIR circuit 763 (O/W). CLEAR the DTCs. CYCLE the ignition OFF then ON. TEST the system for normal operation. REPLACE the GEM; REFER to Section 419-10. CLEAR the DTCs. TEST the system for normal operation.
  • Page 31 1998 F-150/250 Workshop Manual Page 31 of 74 Is the voltage greater than 10 volts? REPLACE the fuse junction panel. CLEAR the DTCs. TEST the system for normal operation. REPAIR circuit 1052 (T/BK). CLEAR the DTCs. TEST the system for normal operation. B4 CHECK THE IGNITION STATES —...
  • Page 32 1998 F-150/250 Workshop Manual Page 32 of 74 If DTC P1812, GO to If DTC P1815, GO to If DTC P1819, GO to If DTC P1820, GO to Pinpoint Test If DTC P1822, GO to Pinpoint Test If DTC P1824, GO to Pinpoint Test If DTC P1826, GO to Pinpoint Test...
  • Page 33 1998 F-150/250 Workshop Manual Page 33 of 74 Does the GEM PID indicate 2WD? GO to B9. GO to B11. B9 CHECK THE 4WD MODE SWITCH — MONITOR THE GEM PID 4WDSGEM (4H) Place the mode switch in the 4H position. Does the GEM PID indicate 4WDHGH? GO to B10.
  • Page 34 1998 F-150/250 Workshop Manual Page 34 of 74 Measure the resistance between mode switch terminals 2 and 3. Is the resistance between 3700 and 4100 ohms? GO to B12. REPLACE the mode switch. REFER to Section 308-07B. CLEAR the DTCs. TEST the system for normal operation.
  • Page 35 1998 F-150/250 Workshop Manual Page 35 of 74 Measure the resistance between the mode switch terminals 2 and 3. Is the resistance between 340 and 380 ohms? GO to B14. REPLACE the mode switch. REFER to Section 308-07B. CLEAR the DTCs. TEST the system for normal operation.
  • Page 36 1998 F-150/250 Workshop Manual Page 36 of 74 Is the resistance greater than 10,000 ohms? GO to B16. REPAIR circuit 780 (DB). CLEAR the DTCs. TEST the system for normal operation. B16 CHECK CIRCUIT 780 (DB) FOR SHORT TO POWER Measure the voltage between GEM C241-8, circuit 780 (DB), and ground.
  • Page 37 1998 F-150/250 Workshop Manual Page 37 of 74 Is the resistance greater than 10,000 ohms? GO to B19. REPAIR circuit 682 (DB). CLEAR the DTCs. TEST the system for normal operation. B19 CHECK CIRCUIT 682 (DB) FOR SHORT TO POWER Measure the voltage between GEM C239-21, circuit 682 (DB), and ground.
  • Page 38 1998 F-150/250 Workshop Manual Page 38 of 74 BPP Switch C252 Measure the voltage between BPP switch C252, circuit 10 (LG/R), and ground. Is the voltage greater than 10 volts? GO to B22. CHECK fuse junction panel 13 (15A). REPLACE if necessary. If fuse junction panel 13 (15A) is OK, REPAIR circuit 10 (LG/R).
  • Page 39 1998 F-150/250 Workshop Manual Page 39 of 74 Verify the GEM PID CLTCHSW displays ACTIVE. Verify that the GEM PID CLTCHSW indicates notACT when the transmission is in any position other than NEUTRAL or PARK. Do the GEM PIDs display correctly? GO to B24.
  • Page 40 1998 F-150/250 Workshop Manual Page 40 of 74 Verify the GEM PID NTRL_SW displays notNTRL. Connect a jumper wire between digital TR sensor C182-7, circuit 57 (BK), and C182-8, circuit 463 (R/W). Does the GEM PID NTRL_SW indicate NTRL? REPLACE the digital TR sensor; REFER to Section 307-01A Section 307-01B.
  • Page 41 1998 F-150/250 Workshop Manual Page 41 of 74 Is the resistance less than 5 ohms? GO to B29. REPAIR circuit 676 (PK/O). CLEAR the DTCs. TEST the system for normal operation. B29 CHECK CIRCUIT 679 (GY/BK) FOR OPEN Fuse Junction Panel C243 Measure the resistance between VSS C186, circuit 679 (GY/BK), and fuse junction panel C243-21, circuit 679 (GY/BK).
  • Page 42 1998 F-150/250 Workshop Manual Page 42 of 74 REPLACE the vehicle speed sensor; REFER to Section 303-14. CLEAR the DTCs. TEST the system for normal operation. REPLACE the fuse junction panel. CLEAR the DTCs. TEST the system for normal operation. B31 CHECK THE CONTACT PLATE SWITCHES —...
  • Page 43 1998 F-150/250 Workshop Manual Page 43 of 74 Does the GEM PID PLATE_A not indicate OPEN? GO to B34. GO to B33. B33 CHECK CIRCUIT 771 (P/Y) TO THE CONTACT PLATE SWITCH A — MONITOR THE GEM PID PLATE_A Connect a jumper wire between transfer case assembly C201-5, circuit 771 (P/Y), and C201- 10, circuit 762 (Y/W).
  • Page 44 1998 F-150/250 Workshop Manual Page 44 of 74 Is the resistance less than 5 ohms? GO to B36. REPAIR circuit 771 (P/Y). CLEAR the DTCs. TEST the system for normal operation. B36 CHECK CIRCUIT 771 (P/Y) FOR SHORT TO POWER Measure the voltage between transfer case assembly C201-5, circuit 771 (P/Y), and ground.
  • Page 45 1998 F-150/250 Workshop Manual Page 45 of 74 Is the resistance less than 5 ohms? GO to B39. REPAIR circuit 762 (Y/W). CLEAR the DTCs. CYCLE the ignition OFF then ON. TEST the system for normal operation. B39 MONITOR THE GEM PID PLATE_B FOR OPEN Monitor the GEM PID PLATE_B.
  • Page 46 1998 F-150/250 Workshop Manual Page 46 of 74 Is the resistance greater than 10,000 ohms? REPLACE the GEM; REFER to Section 419-10. CLEAR the DTCs. TEST the system for normal operation. REPAIR circuit 770 (W). CLEAR the DTCs. CYCLE the ignition OFF then ON. TEST the system for normal operation.
  • Page 47 1998 F-150/250 Workshop Manual Page 47 of 74 REPAIR circuit 770 (W). CLEAR the DTCs. CYCLE the ignition OFF then ON. TEST the system for normal operation. REPLACE the GEM; REFER to Section 419-10. CLEAR the DTCs. TEST the system for normal operation.
  • Page 48 1998 F-150/250 Workshop Manual Page 48 of 74 normal operation. REPAIR circuit 764 (BR/W). CLEAR the DTCs. CYCLE the ignition OFF then ON. TEST the system for normal operation. B47 CHECK CIRCUIT 764 (BR/W) FOR OPEN GEM C241 Measure the resistance between transfer case assembly C201-9, circuit 764 (BR/W), and GEM C241-19, circuit 764 (BR/W).
  • Page 49 1998 F-150/250 Workshop Manual Page 49 of 74 GO to B50. B50 CHECK CIRCUIT 763 (O/W) TO THE CONTACT PLATE SWITCH D — MONITOR THE GEM PID PLATE_D Connect a jumper wire between transfer case assembly C201-10, circuit 762 (Y/W), and C201-13, circuit 763 (O/W).
  • Page 50 1998 F-150/250 Workshop Manual Page 50 of 74 Measure the resistance between transfer case assembly C201-9, circuit 763 (O/W), and GEM C241-18, circuit 763 (O/W). Is the resistance less than 5 ohms? GO to B53. REPAIR circuit 763 (O/W). CLEAR the DTCs. TEST the system for normal operation. B53 CHECK CIRCUIT 763 (O/W) FOR SHORT TO POWER Measure the voltage between transfer case assembly C201-13, circuit 763 (O/W), and ground.
  • Page 51 1998 F-150/250 Workshop Manual Page 51 of 74 GO to C4. GO to C2. C2 CHECK FUSE JUNCTION PANEL FUSE 15 (5A) AND POWER DISTRIBUTION BOX FUSE 22 (50A) Fuse 15 (5A) Fuse 22 (50A) Are the fuses OK? GO to C3. REPLACE the fuse(s).
  • Page 52 1998 F-150/250 Workshop Manual Page 52 of 74 REPAIR ignition circuit(s) (RUN/ACC: circuit 297 [BK/LB], RUN: circuit 1040 [R/LB], START: circuit 32 [R/LB] or circuit 481 [GY/Y] in question. CLEAR the DTCs. TEST the system for normal operation. C5 RETRIEVE THE DIAGNOSTIC TROUBLE CODES (DTCS) Retrieve and Document Continuous DTCs Clear Continuous DTCs GEM On-Demand Self-Test...
  • Page 53 1998 F-150/250 Workshop Manual Page 53 of 74 Does the indicator illuminate correctly? GO to C7. GO to Pinpoint Test C7 CHECK THE LOW LAMP INDICATOR — TRIGGER THE GEM ACTIVE COMMAND LOW LAMP ON Trigger the GEM active command LOW LAMP to ON, then OFF. The LOW indicator should illuminate, then turn off.
  • Page 54 1998 F-150/250 Workshop Manual Page 54 of 74 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.
  • Page 55 1998 F-150/250 Workshop Manual Page 55 of 74 4WD Vacuum Solenoid C180 2WD Vacuum Solenoid C181 GEM C241 Measure the voltage between 4WD vacuum solenoid C180, circuit 605 (R), and ground; and between 2WD vacuum solenoid C181, circuit 145 (GY/BK), and ground. Is any voltage indicated? REPAIR the circuit(s) in question.
  • Page 56 1998 F-150/250 Workshop Manual Page 56 of 74 2WD Vacuum Solenoid C181 Measure the voltage between 4WD vacuum solenoid C180, circuit 294 (W/LB), and ground; and between 2WD vacuum solenoid C181, circuit 294 (W/LB), and ground. Are the voltages greater than 10 volts? GO to C17.
  • Page 57 1998 F-150/250 Workshop Manual Page 57 of 74 REPLACE the 2WD vacuum solenoid. CLEAR the DTCs. TEST the system for normal operation. C19 CHECK CIRCUIT 145 (GY/BK) FOR OPEN GEM C241 Measure the resistance between GEM C241-2, circuit 145 (GY/BK), and 2WD vacuum solenoid C181, circuit 145 (GY/BK).
  • Page 58 1998 F-150/250 Workshop Manual Page 58 of 74 Is the resistance greater than 10,000 ohms? REPLACE the GEM; REFER to Section 419-10. CLEAR the DTCs. TEST the system for normal operation. REPAIR circuit 605 (R). CLEAR the DTCs. TEST the system for normal operation. C23 CHECK THE VACUUM AT THE 4WD AND 2WD VACUUM SOLENOIDS Verify the vacuum (with the engine running) at the feed lines on the 2WD and 4WD vacuum solenoids.
  • Page 59 1998 F-150/250 Workshop Manual Page 59 of 74 Trigger the GEM active commands AXLE ENGG and AXLE DSCN to ON. Apply vacuum and verify that the vacuum solenoids are open. Are the solenoids open? RELEASE the applied vacuum. GO to REPLACE the vacuum solenoid(s) in question.
  • Page 60 1998 F-150/250 Workshop Manual Page 60 of 74 GO to D2. D2 CHECK FUSE JUNCTION PANEL FUSE 15 (5A) AND POWER DISTRIBUTION BOX FUSE 22 (50A) Fuse 15 (5A) Fuse 22 (50A) Are the fuses OK? GO to D3. REPLACE the fuse(s). CLEAR the DTCs. TEST the system for normal operation. If the fuse(s) fails again, CHECK for a short to ground.
  • Page 61 1998 F-150/250 Workshop Manual Page 61 of 74 Retrieve and Document Continuous DTCs Clear Continuous DTCs GEM On-Demand Self-Test Are any DTCs recorded? If DTC B1342, REPLACE the GEM; REFER to Section 419-10. CLEAR the DTCs. TEST the system for normal operation. If DTC P1804, GO to If DTC P1806, GO to If DTC P1808, GO to...
  • Page 62 1998 F-150/250 Workshop Manual Page 62 of 74 If the PID displays OFFO-G and lamp stays on continuously, GO to If the PID displays OFFO-G and the lamp does not illuminate, REFER to Section 413-01A. D7 CHECK THE GEM FOR SHORT TO GROUND GEM C241 Is the lamp still illuminated? GO to D8.
  • Page 63 1998 F-150/250 Workshop Manual Page 63 of 74 GEM C241 Measure the voltage between: 4x4 HIGH: GEM C241-9, circuit 210 (LB), and ground. 4x4 LOW: GEM C241-10, circuit 975 (BR/Y), and ground. Is any voltage indicated? REPAIR circuit 210 (LB) and/or 975 (BR/Y). CLEAR the DTCs. TEST the system for normal operation.
  • Page 64 1998 F-150/250 Workshop Manual Page 64 of 74 GEM On-Demand Self-Test Are any DTCs recorded? If DTC B1342, REPLACE the GEM; REFER to Section 419-10. CLEAR the DTCs. TEST the system for normal operation. If DTC P1804, GO to Pinpoint Test If DTC P1806, GO to Pinpoint Test If DTC P1808, GO to...
  • Page 65 1998 F-150/250 Workshop Manual Page 65 of 74 Trigger the GEM active commands AXLE ENGG to OFF and AXLE DSCN to ON. Spin one front tire and the other front tire should not spin. Is the axle disconnect working properly? The 4x4 system is working properly.
  • Page 66 1998 F-150/250 Workshop Manual Page 66 of 74 Is any voltage indicated? REPAIR circuit 976 (O). CLEAR the DTCs. TEST the system for normal operation. REPLACE the GEM; REFER to Section 419-10. CLEAR the DTCs. TEST the system for normal operation. E7 CHECK THE ESOF CLUTCH RELAY COIL CIRCUIT —...
  • Page 67 1998 F-150/250 Workshop Manual Page 67 of 74 E9 CHECK THE ESOF CLUTCH RELAY Check the ESOF clutch relay; refer to Component Test. Is the ESOF clutch relay OK? GO to E10. REPLACE the ESOF clutch relay. CLEAR the DTCs. TEST the system for normal operation. E10 CHECK CIRCUIT 976 (O) FOR SHORT TO GROUND GEM C241 Measure the resistance between ESOF clutch relay connector pin 2, circuit 976 (O), and...
  • Page 68 1998 F-150/250 Workshop Manual Page 68 of 74 Transfer Case Assembly C201 Trigger the GEM active command SHFT CLCH to ON. Measure the voltage between transfer case assembly C201-16, circuit 779 (BR), and ground. Is the voltage greater than 10 volts? GO to E13.
  • Page 69 1998 F-150/250 Workshop Manual Page 69 of 74 ESOF Clutch Relay Transfer Case Shift Relays C221 Measure the voltage between ESOF clutch relay connector pin 5, circuit 779 (BR), and ground. Is any voltage indicated? REPAIR circuit 779 (BR). CLEAR the DTCs. TEST the system for normal operation. REPLACE the ESOF clutch relay.
  • Page 70 1998 F-150/250 Workshop Manual Page 70 of 74 Is the resistance less than 5 ohms? REPLACE the ESOF clutch relay. CLEAR the DTCs. TEST the system for normal operation. REPAIR circuit 779 (BR). CLEAR the DTCs. TEST the system for normal operation. E17 CHECK THE TRANSFER CASE SYNCHRONIZATION Raise and support the vehicle.
  • Page 71 1998 F-150/250 Workshop Manual Page 71 of 74 turning the ignition switch to START. Monitor the GEM PID IGN_GEM while turning the ignition switch through the START, RUN, OFF, and ACC positions. Do the PID values agree with the ignition switch positions? GO to F2.
  • Page 72 1998 F-150/250 Workshop Manual Page 72 of 74 GEM C267 Fuse Junction Panel C243 Measure the voltage between fuse junction panel C267 terminal 4, and ground; and between fuse junction panel C267 terminal 16, and ground. Are the voltages greater than 10 volts? GO to F8.
  • Page 73 1998 F-150/250 Workshop Manual Page 73 of 74 Is the resistance greater than 10,000 ohms? REPLACE the fuse junction panel. CLEAR the DTCs. TEST the system for normal operation. REPAIR circuit 1052 (T/BK). CLEAR the DTCs. TEST the system for normal operation. F7 CHECK THE FUSE JUNCTION PANEL Fuse Junction Panel C243 Measure the resistance between fuse junction panel C243 terminal 11 and fuse junction panel...
  • Page 74 1998 F-150/250 Workshop Manual Page 74 of 74 Measure the resistance between GEM C239-14, circuit 875 (BK/LB), and ground. Is the resistance less than 5 ohms? REFER to Section 418-00. REPAIR circuit 875 (BK/LB). CLEAR the DTCs. TEST the system for normal operation. F10 CHECK THE FUSE JUNCTION PANEL FOR SHORT TO GROUND Measure the resistance between fuse junction panel C267 terminal 4, and ground.

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F-250 1998