Ben Owner/Technician Minnesota Posted Latest
2016 Ford F-150 Lariat 3.5L (G) 6-spd (6R80) — 1FTFX1EGXG⦁⦁⦁⦁⦁⦁⦁
Truck Is Mechanicaly in 4X4 While the Mode Selector Switch Is in 2H
This Truck came in with the customer stating that he thought the brakes were dragging. He also said that there was a rubbing and jerking feeling while turning. Took a short test drive and it is clear that the truck is in 4X4. No code for the 4X4 are present, ran pinpoint test L and it concludes that the TCCM is faulty. I'm having a hard time just throwing a module at it since i don't clearly understand this t-case operation. it has the torque on demand t-case which according to service data uses an electronic clutch to engage the 4x4. I can't seem to find and testing procedures for the T-case itself. If for example the clutch has failed and “welded itself together” it wouldn't matter what the TCCM commanded it to do it would always provide full power to the front drive shaft. The concern was noticed since someone has previously removed and capped off the vacuum source to the IWE system so the truck has a “live” front axle.
The only other thing of note is that there is a pending code for the pedal position switch D/E. I have tested the throttle pedal and it is faulty and will be replaced. I read in service data the the TCCM use inputs including the throttle pedal to determine how it engages the clutch, however it is un clear if the faulty pedal would cause a default 4x4 engagement.
I would appreciate any thoughts any one may have on this.
Thanks,
Ben
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AiDN AI Assistant
California
AiDN
This is a reply from an experimental AI-powered advisor. It is important to exercise caution, verify information from multiple sources, and make informed decisions based on the prevailing circ*mstances.
Ben, since you've already run pinpoint test L and suspect the TCCM, it's critical to ensure that the transfer case itself isn't mechanically stuck in 4HI before replacing any modules. Since the truck has a torque-on-demand transfer case, the clutch mechanism inside the transfer case could indeed be the issue if it has failed and is causing constant engagement.Here’s a step-by-step approach you…
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Chris Technical Support Specialist
New Jersey
Chris
If you disconnect the TCCM, it cant command it on, check for operation with TCCM disconnected
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Trent Technician
Pennsylvania
Trent
Two things: first of all, if you restored the vacuum system to the IWE's, then it would go into 2WD mode even if the front driveshaft is spinning. Right? Also, I believe the test for the transfer case 4x4 clutch would be if the TCCM is commanding it on or off and the actuator is receiving a signal or moving then the fault would lie with the transfer case itself.
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Dan Owner/Technician
Texas
Dan
… Ben … see if the front hubs HOLD VACUUM after the engine is shut off… they should… and when rotating just the wheels (key off) they should NOT spin the axles. (gas motor off).… Hobbs
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Ben Owner/Technician
Minnesota
Ben Update
I tested the IWE system from the vac solenoid to the IWE's no leaks found with the smoke machine and everything holds vacuum. the section of line from the vacuum canister to the truck vacuum system had be previously removed rendering the IWE's in the always locked position. Replaced that set of lines and tested, IWE's are now working as designed. I took a sample of the oil from the T-Case and it…
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Chris Owner/Technician
Maryland
Chris
Ben, ford had a tsb on some of these vacuum IWE f150s. In the tsb they tell you to block off the vacuum lines because the system was so problematic and unreliable.The main issue with the iwe system is partial engagement & the noise that makes due to vacuum leaks or low vacuum. I’ve disabled the vacuum on several of them with no ill effects. Pull the line off at the knuckle & install a…
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