LEMON Manuals: Even more car manuals for everyone
Home >> Ford >> 2000 >> Excursion 7.3 F, 4WD >> Repair and Diagnosis >> Transmission >> Transfer Case >> Four-Wheel Drive Systems (ESOF) - Excursion & F250-F550 Super Duty >> Diagnostic Tests >> Test C: Front Axle Not Engaging Properly

Test C: Front Axle Not Engaging Properly

  1. Retrieve DTCs

    Turn ignition off. Connect NGS tester. Retrieve and document continuous DTCs. See RETRIEVING DIAGNOSTIC TROUBLE CODES  under DIAGNOSIS & TESTING. Clear continuous DTCs. Retrieve on-demand DTCs. See GEM ON-DEMAND SELF-TEST  under DIAGNOSIS & TESTING. If DTCs are retrieved, go to appropriate step(s). See DTC-TO-TEST STEP INDEX  table. If no DTCs are retrieved, go to next step.
    DTC-TO-TEST STEP INDEX

    DTC Go To Test Step
    P1832  2
    P1834  5
    P1876  5
    P1877  7

  2. Check Circuit 295 (Light Blue/Pink Wire) For Voltage To PVH Solenoid

    Turn ignition off. Disconnect PVH solenoid 3-pin connector. Turn ignition on. Measure voltage between center PVH solenoid terminal No. 2 (Light Blue/Pink wire) and ground. If voltage is more than 10 volts, go to next step. If voltage is 10 volts or less, repair Light Blue/Pink wire. Clear DTCs and retest system.

  3. Check Circuits 145 (Gray/Black Wire) & 605 (Red Wire) For Short To Voltage

    Turn ignition off. Disconnect PVH solenoid connector. Turn ignition on. Measure voltage between ground and Red wire terminal at PVH solenoid connector. Measure voltage between ground and Gray/Black wire terminal at PVH solenoid connector. If voltage is present, repair suspect circuit for short to voltage. Clear DTCs and retest system. If voltage is not present, go to next step.

  4. Check Circuits 145 (Gray/Black Wire) & 605 (Red Wire) For Short To Ground

    Measure resistance of Gray/Black wire between PVH solenoid and ground, and then between Red wire and ground. If resistances are more than 10 k/ohms, go to next step. If resistances are 10 k/ohms or less, repair appropriate circuit. Clear DTCs and retest system.

  5. Check Circuits 145 (Gray/Black Wire) & 605 (Red Wire) For Open

    Disconnect GEM C240C connector (22-pin). Measure resistance of Gray/Black wire between PVH solenoid and GEM connector C240C (22-pin) terminal No. 7. See Figure. Measure resistance of Red wire between PVH solenoid and GEM 22-pin connector terminal No. 6. If resistances are less than 5 ohms, go to next step. If resistances are 5 ohms or more, repair appropriate circuit. Clear DTCs and retest system.

  6. Check PVH Solenoid Coils

    Measure resistance between terminal No. 1 (Red wire) and No. 3 (Gray/Black wire), and then between terminal No. 2 (Light Blue/Pink wire) and No. 3 at PVH solenoid. If resistance is 45-55 ohms, go to step  27. If resistance is not 45-55 ohms, replace PVH solenoid. Clear DTCs and retest system.
    7. NOTE: The following steps require the use of a vacuum gauge accurate to within 0.1" Hg.

  7. Check Engage Vacuum To Right Knuckle
    Place hublocks in AUTO position. Raise and support vehicle. Start engine and let idle. Place mode switch in 2WD position. Wait 15 seconds. Disconnect vacuum line at right front knuckle and install vacuum gauge in-line. Disconnect vacuum line at left front knuckle and plug line. Place mode switch in 4X4 HIGH. Check vacuum reading for 45 seconds. If vacuum reading is more than 10" Hg, go to next step. If vacuum reading is 10" Hg or less, go to step  17.

  8. Check Disengage Vacuum To Right Knuckle

    Place mode switch in 2WD position. Check vacuum reading for 15 seconds. If vacuum reading is 5.8-7.3" Hg, go to next step. If vacuum reading is not as specified, go to step  18.

  9. Check Mechanical Engagement At Right Axle

    Remove vacuum gauge and reconnect right vacuum line. Place mode switch in 4X4 HIGH. Wait one minute. Rotate right front wheel one revolution while observing right axle shaft and "U" joint. If axle shaft and "U" joint rotate, go to next step. If axle shaft and "U" joint do not rotate, go to step  20.

  10. Check Mechanical Disengagement At Right Axle

    Place mode switch in 2WD position. Rotate right front tire 1 revolution while watching right axle shaft and "U" joint. If axle shaft and "U" joint do not rotate, go to next step. If axle shaft and "U" joint rotate, go to step  20.

  11. Check Engage Vacuum To Left Knuckle

    Remove plug from left vacuum line and install vacuum gauge. Disconnect vacuum line at right front knuckle and plug line. Place mode switch in 4X4 HIGH. Check vacuum reading for 45 seconds. If vacuum reading is more than 10" Hg, go to next step. If vacuum reading is 10" Hg or less, check vacuum harness for damage or obstruction. Repair as necessary. Clear DTCs and retest system.

  12. Check Disengage Vacuum To Left Knuckle

    Place mode switch in 2WD position. Check vacuum reading for 15 seconds. If vacuum is 5.8-7.3" Hg, go to next step. If vacuum is not as specified, check vacuum harness for damage or obstruction. Repair as necessary. Clear DTCs and retest system.

  13. Check Mechanical Engagement At Left Axle

    Remove vacuum gauge and reconnect left vacuum line. Place mode switch in 4X4 HIGH. Wait one minute. Rotate left front wheel one revolution while observing left axle shaft and "U" joint. If axle shaft and "U" joint rotate, go to next step. If axle shaft and "U" joint do not rotate, go to step  20.

  14. Check Mechanical Disengagement At Left Axle

    Place mode switch in 2WD position. Rotate left front wheel one revolution while observing left axle shaft and "U" joint. If axle shaft and "U" joint do not rotate, go to next step. If axle shaft and "U" joint rotate, go to step  20.

  15. Check Left Wheel For Vacuum Leaks

    Turn ignition off. Disconnect left wheel vacuum line from fitting at wheel. Attach hand vacuum pump to knuckle fitting and tee in vacuum gauge between knuckle and pump. Pump hand pump until 20" Hg is reached. Rotate left wheel for 30 seconds while observing vacuum gauge. If vacuum leak exceeds .5" Hg in 30 seconds, go to step  25. If vacuum leak does not exceed .5" Hg in 30 seconds, go to next step.

  16. Check Right Wheel For Vacuum Leaks

    Reconnect left wheel vacuum line to wheel fitting. Disconnect right wheel vacuum line. Attach hand vacuum pump to knuckle fitting and tee in vacuum gauge between knuckle and pump. Pump hand pump until 20" Hg is reached. Rotate right wheel for 30 seconds while observing vacuum gauge. If vacuum leak exceeds .5" Hg in 30 seconds, go to step  25. If vacuum leak does not exceed .5" Hg in 30 seconds, system is operating normally. Test is complete.

  17. Check Manifold Vacuum

    Reconnect all vacuum lines. With engine idling, disconnect vacuum harness from PVH solenoid. Connect vacuum gauge to reservoir output line at PVH solenoid connection. If vacuum reading is more than 10" Hg, go to next step. If vacuum reading is 10" Hg or less, repair vacuum supply as necessary. Clear DTCs and retest system.

  18. Check PVH Solenoid Output In 2WD

    Reconnect vacuum harness to PVH solenoid so only reservoir output line is connected. Connect vacuum gauge to solenoid output port. Start engine. Place mode switch in 4X4 HIGH position. Wait 45 seconds. Place mode switch in 2WD position. If vacuum reading is 5.8-7.3" Hg, go to next step. If reading is not as specified, replace PVH solenoid. Clear DTCs and retest system.

  19. Check PVH Solenoid Output in 4X4 HIGH

    Start engine. Place mode switch in 4X4 HIGH position. Wait 45 seconds. If vacuum reading more than 10" Hg, check vacuum harness for leaks, crimps, restriction, etc. Repair as necessary. Clear DTCs and retest system. If vacuum is 10" Hg or less, replace PVH solenoid. Retest system.

  20. Check For Static Vacuum Leak

    Turn ignition off. Disconnect vacuum line at suspect left or right knuckle. Connect vacuum pump to knuckle fitting and tee in vacuum gauge between knuckle and pump. Pump hand pump until 20" Hg is reached. Observe gauge for 30 seconds. If vacuum leaks less than .5" Hg in 30 seconds, go to next step. If vacuum leaks more than .5" Hg in 30 seconds, go to step  22.

  21. Check For Dynamic Vacuum Leak

    Ensure vacuum remains at 20" Hg. Rotate front wheel for 30 seconds while reading vacuum. If vacuum leaks less than .5" Hg in 30 seconds, replace suspect hublock. Clear DTCs and retest system. If vacuum leaks more than .5" Hg in 30 seconds, go to step  23.

  22. Check For Loose Knuckle Fitting

    Remove vacuum pump and gauge. Ensure knuckle fitting is tightened to 15 ft. lbs. (20 N.m). Reconnect vacuum pump and gauge to knuckle fitting. Pump up vacuum to 20" Hg. If vacuum leaks less than .5" Hg in 30 seconds, go to step  9 for right hublock, or step  13 for left hublock. If vacuum leaks more than .5" Hg in 30 seconds, go to next step.

  23. Check For Hublock Leak

    Remove hublock from suspect wheel. Install seal to close hublock off from vacuum leak. Install vacuum pump and gauge on knuckle vacuum line. Pump up to 20" Hg. If vacuum leaks less than .5" Hg in 30 seconds, go to next step. If vacuum leaks .5" Hg or more in 30 seconds, go to step  25.

  24. Check Hublock Seal

    Remove hublock tool. Reinstall hublock with NEW "O" ring. Install vacuum pump and gauge on knuckle vacuum line. Pump up to 20" Hg. If vacuum leaks less than .5" Hg in 30 seconds, system is operating normally. Clear DTCs and retest system. If vacuum leaks .5" Hg or more in 30 seconds, replace suspect hublock. Clear DTCs and retest system.

  25. Check Knuckle Seal

    Remove hublock from suspect wheel. Remove snap ring and thrust washer. Remove front hub assembly. Install knuckle bore vacuum test tool. Install vacuum pump and gauge on knuckle vacuum line. Pump up to 20" Hg. If vacuum leaks less than .5" Hg in 30 seconds, go to next step. If vacuum leaks .5" Hg or more in 30 seconds, replace knuckle seal. Clear DTCs and retest system.

  26. Check For Leaking Hub

    Reinstall hub assembly with NEW "O" ring. Install vacuum pump and gauge on knuckle vacuum line. Pump up to 20" Hg. If vacuum leaks less than .5" Hg in 30 seconds, reinstall hub assembly and reconnect all disconnect lines. Clear DTCs and retest system. If vacuum leaks .5" Hg or more in 30 seconds, replace hub assembly. Clear DTCs and retest system. If vacuum leak persists, replace suspect hublock. Clear DTCs and retest system.

  27. Check For Correct Module Operation

    Check all connectors for corrosion, pushed out pins and proper seating. Repair as necessary. Connect any disconnected connectors. Operate vehicle and verify if problem is still present. If problem is still present, replace GEM. Clear DTCs and retest system. If problem is not present, system is operating normally. Clear DTCs and retest system.
scientia non olet · About LEMON Manuals