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Sorry, my mind was all over the place last night and I was frozen to the bone.
It is cranking no start. I went out again this morning and plugged in Forscan and here is the screen shot of live data. It does show RPM and it has a code for the Crankshaft Sensor Circuit.
2 things I noticed, first is with the key left on the injector clatter kept going and then the speed was increasing more and more. This must be the latest strategy version to "warm up" the injectors (its 23f outside right now). Didn't have that before. Second, my voltage is low, didn't realize I had worked the batteries that hard before shipping the PCM off, its connected to the battery charger now.
Talked with FICMRepair.com and as always they are super helpful. I need to go probe wires now. Blake said if there is no Crank/Cam Sync, then there will not be a FICM sync (I believe this has been said before) and he believes since it popped a P0335-60 code "Crankshaft Position Sensor Circuit A" that I need to probe those wires. He said it is the center PCM connector 1381C
Crankshaft Sensor:
Pin 30 (dark blue) positive
Pin 41 (orange w/ grey stripe?) ground
300-450 ohms on the sensor when probing from the pins with the full length of the wire
300-400 ohms on the sensor when probing the sensor directly
Back probing the wires when cranking should show 1-5v AC
Camshaft Sensor:
Pin 31 (red) positive
Pin 43 (orange) ground
800-1100 ohms on the sensor when probing from the pins with the full length of the wire
800-1000 ohms on the sensor when probing the sensor directly
Back probing the wires when cranking should show 0.5-1v AC
The wires themselves should be 0 to 3 ohms
Pin 42 is the bare ground wire which splices and wraps both connector lead under the foil wrapping and that should ohm out to infinite when probed to the chassis.
So, this is what I am going to do.... tomorrow when it's above freezing. If anyone has more wiring diagrams and could point me to them or post them here, it'd be really appreciated.
Unplugged the 1381c connector from the PCM, just to be safe also pulled the FICM relay, and did key off engine crank probing the Crankshaft Position Sensor pins and then the Camshaft Position Sensor pins. Both read correct hertz and AC voltage, perfectly in range of what I was told to look for and based on @bismic nice write up I found over on the Powerstroke forum. Was really scratching my head at this point and thought why not plug everything back in and try starting one more time. Put everything back in place and it fired up immediately. While it was running I pushed and pulled on all wires from the backside of the 1381c connector all the way across the engine, jiggling the CMP wires and the CKP wires. Idling smooth. I turned it off and restarted it. Turned it off and moved it in the driveway. Going for a test drive now. It is 44f today, will see if it starts tomorrow morning when its supposed to be in the low 20s. Here are screenshots of Forscan while it was running.
Last edited by misterpeanut; Feb 7, 2026 at 02:20 PM.
The contacts all looked clean and dry. 2 or 3 weeks ago when I found that chaffed wire that I fixed, I sprayed all 3 PCM connectors with CRC Electrical Contact Cleaner, nothing came out, but some say it somehow cleans the metal for better contact.
No new codes, everything looks good to be honest. I'll report back if anything comes up again.
It's frustrating it's "fixed" without definitively finding the "issue". It's driving and running perfectly now... as it was before.
The connectors and the pins in them are notoriously finicky. You wouldn't be the first problem solved by a pin getting moved around by plugging/unplugging. That's why I asked about messing with the FICM connectors, the angle they're at they can be hard to fully seat both locking tabs and that cause cause weird intermittent disconnects between pins and the module.
I have thought the same thing and I will find out soon.
After it mysteriously started on Saturday, it drove great ... until we were stranded Sunday night after the Super Bowl. It started twice, first time it ran for 10 seconds and shut off, cranked multiple times and after messing with the 1381c it started another time and ran for about 30 seconds and then it just shut off. When it shuts off it's a clean stop like someone turned off the key. Got it towed home. Just wanted to share... that 6.7l Cummins in the tow truck sure was powerful and smooth.
Tuesday we "fixed" the problem and bought my wife a 2021 BMW X3. She is as happy as a lark. We both love the Excursion, but who can love that unreliability.
So now the Excursion is sitting in the driveway, and of course it starts just fine. I had it sitting there running for over an hour as I looked over every inch of the harness I could see and touch without loosing fingers in the fan or belt. No matter what I did, I could not get it to cut out. The Engine Wire Harness and FICM Harness are coming off and being inspected on the bench, and now I can take the time to do it thoroughly without the stress of having it running in time for her to drive to work. I can definitely see there are places the Wire Harnesses are pulled super tight and I see visible wear on the outside.
I'll report back with what I find. Might be a few weeks though.
Regarding the engine wire harnesses ... any suggestions. Is it OE only (if I can find it) or are there aftermarket solutions you guys have found to be trustworthy? I see ProSourceDiesel has a lot of offerings.... ?
By the way, tried starting it multiple times and it only cranks at this point.
