Hello all,

I've searched all the f150 forums for symptoms similar to what is going on with mine and haven't found anything. I believe this could be a unique situation so I am asking. I have read all the IWE and 4x4 threads I could find so I have educated myself a bit.

Here is what is going on. Flashing 4x4 hi and lo lights, 4x4 will not engage at all. I have purchased new iwe solenoid and transfer case motor but have not installed. I had my mechanic take a look. He is reporting that the PCM is not sending any 4x4 signals to any of the components. He believes that the PCM was replaced with either the wrong model or one which the 4x4 hardware is broken.

He did not find any problems with the TC, iwe system, or the switch. It's not a shady shop, I believe that they are telling me what they are finding. However, I'm thinking it could possibly be something they are not thinking of that is preventing the PCM from doing it's job in 4x4. I'm going to install the parts I have this weekend and see what happens. Everything else on the truck works perfectly and it runs great in 2wd mode.

If I cannot get anything figured out, I suppose the best thing to do is get a new PCM. However because the PCM was replaced I do not know which model to get, it appears as if I have 3 choices for 2006 FX4's with 4x4. Can this be figured out by VIN? Should I take it to a dealership and become broke with a 900$ PCM plus reprogramming?

 

Until I got to the PCM part of the story I would've bet on the shift motor. Its not IWE related, that won't throw a code. Your timeline is not clear. Did you just recently get this truck and it had this preexisting condition? How did the mechanic determine the PCM had been replaced? To my knowledge the VIN is required to order one.

 

I picked the truck up two weeks ago, I was aware it wouldn't engage 4x4 but everything else was in good shape so I figured I could solve it.

I'm not seeing any dtc codes, just flashing 4x4 hi/lo every two minutes or so. Basically, he was theorizing that PCM was replaced at some point recently. I might pull the PCM out and check the numbers on it, I didnt think to do that. Kinda went with what I was told today from mechanic. Thanks for the reply, it's got me thinking to check that out.

However, It appears to me that it was a f150 fan that had money to take care of it, so I don't think he would of done something like that. Judging from the mods that were done to it and it's condition. Good tires, good shocks, upgraded brakes, HID Kit, spray in bed liner, engine/transmission are perfect, gotts mod on intake. All the right things seem to have been done, it was cared for and used as a truck should be. It wasn't abused.

If the shift motor is shot electronically, would that throw the PCM into a limp mode where it won't do anything until it reads correct resistance from the Transfer case shift motor? The 4x4 lights start flashing when key is turned to on, not after I start it or try to operate 4x4.

 

Its probably the shift motor.

 

if you have a shift motor already install it and see if it fixes the issue..

 

Going to swap shift motors in the morning and do the IWE solenoid at the same time. Took a look at the PCM numbers, it's the right unit. 6L3A-12A650-BPA DCC0. I believe the mechanic is on crack and garage mechanics are right once again.

If the issue is simply the shift motor, I'm never going to that shop again.

 

do not replace the solonoid and shift motor at the same time.. if one fixes then the other can be returned. check your fuses and relays also .

 

Installed the TC motor, no more flashing 4x4 hi/lo lights. So that was a problem that is now fixed. Started the car, turned the 4x4 switch and nothing happens. New TC motor doesn't make a sound. All the wires from the switch to under the dash all look good. I will look at the fuses asap tomorrow morning, I'm good on car issues today.

I suppose either the mechanic was correct and the pcm is whack, bad switch, or something I'm not thinking of.

I checked the iwe solenoid, it is functioning normal. Getting good vacuum.

 

Final Update: It was the PCM, it would not communicate to the 4x4 systems at all. Just the 4x4 section was completely dead, PCM worked fine everywhere else. I put in a reman unit, everything works as it should, front axle is engaging. I tested 4lo for a few feet, then 4hi for a few blocks in a straight line while it was flooding rain outside. Will test on mud next week so I'm off asphalt.

Thanks for everyone's help and the f150forum resources.

 

Glad you got it figured out. I sure didn't expect the PCM.