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Brian, Auto Service Technician
Category: Ford
Satisfied Customers: 1227
Experience:  5 years Ford Technical Hotline/Service Engineer. 2005 Ford Master Cert. Automotive Technology degree
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How do I know if the IWE solenoid is working correctly?

Customer Question

How do I know if I need to replace the hub and or actuator on a 2004 ford f150 non-heritage 4x4. I replaced the driver side hub and actuator hoping it would fix the 4x4, but now the passenger side makes a grinding noise when I try to use the 4x4. The vaccum solenoid seems to be operating correctly, but how can I be sure?

Submitted: 8 years ago.
Category: Ford
Expert:  Brian replied 8 years ago.

Test for vacuum at the lockout (IWE integrated wheel end), there should not be vacuum at the lock out when in 2wd and there should be vacuum when in 4wd, if you check both sides and there is vacuum on both sides the lockout (IWE integrated wheel end) is likely bad.
A Ford dealer can scan the 4x4 system for codes, which may reveal the tell-tale codes for the solenoid. There is a TSB (Technical Service Bulletin) saying to replace the solenoid. The new part is updated to prevent water from getting into the vacuum lines and causing blockages. You can disconnect the lines at the solenoid and at the wheel end and blow the lines out with compressed air. Water may have entered the Integrated Wheel End IWE, and damaged it. So the passenger side may need to be replaced too.
TSB 06-8-15

FORD:2004-2006 F-150
LINCOLN:2006 Mark LT


Some 2004-2006 F-150 and 2006 Mark LT 4X4 vehicles built before 4/24/2006 may exhibit a noise in*****from the front Integrated Wheel Ends (IWE) and/or the 4X4 system being inoperative. The IWE solenoid may have ingested water and passed it to the IWE system causing water contamination in the vacuum portion of the system. A shorted IWE solenoid can set the codes C1979 and C1980. If either code is present, the 4WDH light will be inoperative.


Use the following Service Procedure to check and repair the 4X4 system.


  1. Replace the IWE solenoid. Torque the new design bracket and solenoid to 62 lb-in (7 N-m). It will be necessary to remove the vacuum lines from each IWE down at the wheels to check for water being present.
    1. If no water is present at the vacuum line at the IWE, install the new solenoid with bracket. Reconnect all vacuum hoses.
    2. If water is present allow it to drain from the vacuum lines. Then follow the updated procedure outlined in 2006 Workshop Manual (WSM) on-line version, Section 308-07A, Pin Point Tests B21 and B22. These tests checks IWE leak rates with vacuum and will remove any residual water from the IWE. Reconnect all vacuum hoses.
  2. If the IWE looses vacuum quicker than specification. Refer to WSM, Section 204-01B for normal diagnostic procedures.
6L3Z-9E441-AIWE Solenoid

Description and Operation info:

Integrated Wheel End (IWE) System

The integrated wheel end (IWE) system consists of the:

  • Vacuum reservoir
  • IWE solenoid
  • IWEs (spring loaded vacuum hubs)
  • Vacuum hoses
  • Check valve

The IWE system uses vacuum hubs that engage or disengage the front wheel hubs from the front halfshafts.

The IWE solenoid receives engine vacuum from the vacuum reservoir.

When the four wheel drive system is in 2H mode, 4X4 control module (PCM) supplies a ground path to the IWE solenoid to apply vacuum to the integrated wheel ends (disengaging the front hubs from the front halfshafts). In 4WD mode, the 4X4 control module (PCM) does not supply the ground path to the IWE solenoid, vacuum is not applied to the integrated wheel ends and an internal spring keeps the front hubs engaged to the front halfshafts.

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What it boils down to is this: The solenoid is probably bad, and water has probably damaged that IWE on the passenger side. Check the lines, get the water out and make sure that the lines and the IWE's hold vacuum by using a vacuum pump connected at the solenoid to test everything, or connect it at the IWE's to test them individually. Repair any leaks in the lines as needed.

Customer: replied 8 years ago.

I checked for vacuum where the line meets the actuator in 2wd and there is, when I put in 4wd high the vacuum is gone. So I'm assuming I need to replace the actuator and possibly the hub.

Expert:  Brian replied 8 years ago.

Yes, it sounds like the actuator solenoid is working to control vacuum, but it may have allowed water in over time, damaging the IWE at the hub. You can test the ability of the IWE to hold vacuum by connecting it to a hand held vacuum pump. If vacuum leaks down fast compared to your new one on the driver side, it will need to be replaced.
Even though the actuator solenoid is working, I would replace it to prevent future problems. The fact that the TSB is out there basically means there was a definite problem with the original part, and the new part should be significantly improved for a definite long term fix.

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Customer: replied 8 years ago.

Thanks for the information. I will order the new solenoid, hub, and actuator.