Won't Start With Key After FICM Replacement

mchan68 · November 3, 2010

I knew I should've called in sick today. Okay here's a really weird one guys. A truck came in on the hook yesterday as a no-start. Get ready for this. It is a '99 model year truck that SUPPOSEDLY had a 7.3L originally in it (even though the VIN shows it as an 'S' which is a V10 gasser), but the owner and a "mechanic friend" swapped out the drivetrain, including wiring and dash from an '06 6.0L truck. I know, you guys are probably asking WHY in the hell anyone would want a shit litre over a 7.3L.

I go to crank it this morning. The batteries are as flat as can be. So I hook up booster cables to the one battery and a vehicle on one side, and a booster pack to the other battery. At this point, I got my favourite 6.0L no-start PIDs loaded up. Crank it over, and sputters, farts and sneezes like it "tries" to start. All the while, I notice my FICM voltages dropping like dead flies. Soooooo, off I go to grab my tester FICM to plug in. BOOM, she fires up right away. So, off I go to quote a new FICM replace and program.

After some arguing between the owner and the parts department over the price of a new FICM, I finally get the go ahead to replace and program a new one. After programming the new one in with ZERO issues, I try to start it, it won't crank over! WTF? And here's the kicker. With the key in the RUN position, it starts if I jumper it with the jump starter wire, and runs fine (FICM volts all good between 49.5 to 50.0). I also notice the "check gauges" message, "wrench light" remain on while the coolant temp gauge no longer works (even though I get EOT of 226 an ECT of 213 readings, but that's a whole 'nother story).

Anyone ever run into this before?

joshbuys · November 3, 2010

what VIN is stored in the pcm/ficm/tcm? does it have the VIN from the '06 the motor was taken from or does it have the VIN from the '99 truck that now posesses said motor?

mchan68 · November 4, 2010

Figured it out. After programming the new FICM into the truck, for some strange reason, the PCM wouldn't supply the ground on CKT 329 to the starter relay to energize the starter relay. After a brainfart, I borrowed a PCM from a 2006 truck on our lot that I just installed head studs into, and swapped into said truck. Sure enough, the truck fired up right away (and the "check gauges" message as well as the wrench light disappeared). Just for S & G's, I tried to start another PCM reprogram session and it showed the current module calibration level as 4U7A-12A650-BFJ, which if I'm not mistaken is the most current calibration for a late-build 2004 model year truck. I believe for a 2006, it should be 6U7A-12A650-FFE if memory serves me correctly. I guess this also explains the P0487 and P0488 DTCs for the EGR throttle circuits since a 2006 truck doesn't have one.

mchan68 · November 22, 2010

Okay, the guy came back with a PCM he bought from a boneyard. Plugged it in. NO GO. I was able to determine very quickly the PCM he supplied me with is for a 6.8L V10 gasser!!! This I was able to verify quickly be entering in the PCM tag ID# of 6C3A-12A650-CYB. Now, here's the kicker. The PCM he has in his vehicle presently (that now won't supply the ground side circuit to the starter relay when the key is cranked to the START position since the FICM replacement) has a tag ID# of 6C3A-12A650-BZB which tells me that the PCM is in fact originally from a 2006 model year. The question I have is WHY and HOW replacing the FICM would've ended up loading a 2004 model year calibration into it? This time, I "borrowed" a PCM off a 2006 F-550 4x4 that we have on our lot. Sure enough, swapping it in, immediately enables the truck to start with the key. I guess the search continues for another 2006 model year 6.0L F-250/F-350 PCM. Something else that bothers me is why I can't just simply load up As-Built data from any 2006 model year PCM into the existing PCM he has in it right now.