coolride

Hi,
I just bought an 03 F150 4.2l 5spd 4x4.
Engine light was on, PO told me it was due to O2 sensors. He gave me 3 of the 4 to replace them.
So here's what I have found do far. Only code in the system P1633, KAM voltage

So after a ton of research and a lot of digging around the truck, I haven't gotten to far. My fuses are all good, relays are working, connections seem good, grounds are clean and intact. Battery has good voltage and connections are good.
I am a little stuck here. I'm wondering if the truck needs a PCM? I found a lot of pinouts for the PCM, but the ones I found aren't specifically for a 2003 F150, they are for 97's or diesels,etc.
Does anyone have a picture of the PCM plug that describes the pin numbers and which one should be the power and ground for the KAM circuit?
Also, this truck had some engine work prior to me buying it. I think it may have been power washed, not sure if water got blown into a connection somewhere shorting it and causing this? Just a thought, no clue if that has happened. The truck does run, it seems to run rich on start up and if you hammer the throttle down quick. It also seems to idle a little high. I can't clear the 1633 code, it comes back as soon as I clear it, truck running or not.
I'm not sure if a better scanner could give me better info? I am using an old one. But I am really wondering if there is a way to test the PCM to see if it is good before I spend more hours looking for a ghost?
Thanks for any help!

Frank_Ford

The PCM is located inside the cab behind the kick plate in front of the passengers door. Under the hood on the passengers side at the firewall you will see a bundle of wires going into a plug. This plug is held by a single bolt that screws into your PCM inside the cab. Unscrew the bolt and pull the plug and this will disconnect your PCM. I would try hosing this plug down with WD 40 to remove any moisture or bad connections. Replug it and see if that fixes your problem. Important note : DISCONNECT YOUR BATTERY BEFORE WORKING ON THE PCM. HANDLE THE PLUG GENTLY AND USE CARE WHEN REMOVING AND REINSTALLING PLUG SO AS NOT TO BEND ANY CONNECTORS.

If you have to remove the PCM, remove the kick plate inside the cab. Remove a latch and two bolts and then remove the PCM. The PCM has all the part numbers you need for a replacement. NOTE: The PCM is the largest of two boxes behind the kick plate. The small one is the control for your air bags. The larger one (about 10" x 8") is the PCM.

Since you just bought this truck, I would not trust that the PCM is the correct one for your truck. In fact, one guess would be that the guy who sold you the truck got rid of it because of the PCM problem. Another guess would be that they cleaned up the engine compartment before selling the truck and they got water where it shouldn't be. To make sure you get the correct PCM, spend some time at FordParts.com. Put in your VIN number and look up your PCM. Compare this to the PCM in your truck.

Final note: Take your time in figuring this out. Look at what is going on with your truck, what work has been done, and don't jump to conclusions or start fixing stuff before you cover your bases. Lots of problems with vehicles and any machine occurs by trying to fix something and then breaking something else.

coolride

Thats a good idea making sure I even have the right PCM. I have already pulled the battery and PCM harness plug. I looked for any sign of damaged wires or corroded pins or anything like that. Everything looked OK, but there was a little bit of dirt , more kind of like dust in the PCM port, and on the plug. Not sure if it got there from age or from a power washer forcing it in there, or worse yet if it was under water?? Hard saying. It seems the guy I got it from knows more than he lets on but I'm done talking to him about it. Maybe my best bet is like you say, pull the PCM, and find out if it is even right for the truck. Somewhere I did run across a list of PCM's by part number for specific years and engine/trans setups. I'm wondering if the truck was flooded. Seems to have dusty looking stuff in weird places, kind of what you'd expect from something that went mudding and got sunk, then washed up? The only reason I say that is because the dusty like stuff is so fine, like powder. Its in the fuse panel, the heater ducts,etc. It could also be just that it lived a while on a dirt road and just got into stuff.
At any rate, whatever happened to it I will never know. But I will look into the PCM part numbers. Maybe it has a V-8 PCM, and it just doesn't like my v-6. And maybe that PCm isn't any good. Any idea if there's a way to bench test the PCM, send it out or whatever? I don't mind buying one if it needs it, just don't want to start changing parts without a little proof of whats wrong. I'd rather take the time to diagnose it so I know it is actually fixed.
And if I replace the PCM, does it need to go to Ford for the Key transponder? Or is that a separate controller that works with the PCM?
Thanks for the help!

Carcrazygts2

KAM errors are caused by a bad PCM. There is other codes stored but a normal scanner will not pick them up. I am certain you also have a P0600 which is a PCM memory allocation error. Only the Ford IDS can pickup a P0600 because where its gets stored.

coolride

If the PCM is toast, can I replace it without messing with the keys? I find people saying you need to reprogram key at Ford, and other people say you can put in a new/used PCM without doing that. If it comes to replacing the PCM, I don't want to disable the truck here in the yard if it needs to be at Ford.

coolride

So I checked the PCK in the truck. I have a 2L3A-12A650-AGC
I looked on Ford, the new replacement is 2L3Z-12A650-BJC
I found one like what I have on ebay, its for a 2002/03 F150 4.2L 5 spd 2WD. My truck is 4wd.
Not sure if the 2 vs 4wd matters in the computer? Maybe the one in my truck is original? I wonder if the part number changed due to updates after the truck was built? Or maybe I just have a junk yard PCM in my truck that may be no good? Makes it run but not right?
Any thoughts?

Carcrazygts2

Still has to be reprogrammed. Have have 2 keys also.

coolride

So what happens if you have only 1 key? I must say I hate this PATS junk. Doesn't seem to be a good way around it though.
I work with a guy who has some friends at Ford. Shop techs. He is going to talk with them today on this truck. See if I am missing something. I am going to re-check the power and grounds in the PCM harness, and after that I am thinking if it all checks out, probably the PCM is finished. I'll get a replacement and change it and have Ford get the key situation dealt with.
I have 2-12V and 1-5.5V lines going into the PCM from the harness, with key in OFF position. Actually, key not in truck at all.
I didn't have the pinout so I didn't know what number pin the hot ones where. so I will need to pull it again to verify now that I know the pin numbers. I will check the ground and the ones I need to have 12V and go from there. If I have power at the required pins and ground is good, I assume it is safe to say the PCM is done right?

Carcrazygts2

Its a internal issue with the PCM.

coolride

I double checked, from what pinout info I found, I have the power and grounds I need at the harness with key off. Pin 55 has full battery power. All grounds show good. Only questionable pin is pin #3. It is a yellow wire w/black stripe. For some PCM's its a ground, like a 97 f150. Some its a VSS signal. Some its a digital TR sensor, or a contactor low current sense return. If it is a ground in a 2003, I have an issue. If its anything else its probably fine. I'm thinking the PCM is the problem. Everything else is testing good at this point. The guy I got it from had to jump start it just before I looked at it. I wonder if he had the cables on wrong or if he hooked up what ever he boosted it with, with the key ON and it popped something in the PCM.
Looks like I need to start shopping for a new PCM.