Help Needed Dtc 1378 - F-Series & SuperDuty Diesel Forums

pstockman · 01-22-2012, 09:13 PM

DTC 1378 on 05 F350 6L. FICM replaced in December. Truck started fine this morning. Parked for an hour wouldn't start. Initial code P041 indicated Cam sensor. Disconnected batteries as fault seemed spurious but it was still there. Replaced cam position sensor. Code cleared. No start. Tried a couple of times and got DTC 1378 FICM supply voltage low. I have an Edge after market chip and controller.

Any suggestions as best place to go from here? Check out connections at FICM? Check relay? (Any idea which relay to check?) Disconnect the Edge system? Thanks in advance.

DaveBen · 01-22-2012, 11:00 PM

FICMs go bad at about 120,000 miles, or so. You probably need a new FICM or at least a rebuilt one. I did the new Ford FICM in mine. Sorry, no quick fix after the CPS.

Dave

bismic1 · 01-28-2012, 08:39 PM

P1378 is for supply voltage IIRC (Logic Power).

Check out the batteries and alternator.

FYI:
P1378: Low FICM logic power. System detects less than 7 volts. Could be low batteries, loose connections (or excessive circuit resistance), bad relay

01-22-2012, 09:13 PM	#1
pstockman SDD Junior Member Join Date: Jan 2012 Location: Waldorf, MD Posts: 1 Thanks: 1 Thanked 0 Times in 0 Posts	Dtc 1378 DTC 1378 on 05 F350 6L. FICM replaced in December. Truck started fine this morning. Parked for an hour wouldn't start. Initial code P041 indicated Cam sensor. Disconnected batteries as fault seemed spurious but it was still there. Replaced cam position sensor. Code cleared. No start. Tried a couple of times and got DTC 1378 FICM supply voltage low. I have an Edge after market chip and controller. Any suggestions as best place to go from here? Check out connections at FICM? Check relay? (Any idea which relay to check?) Disconnect the Edge system? Thanks in advance.

01-22-2012, 11:00 PM	#2
DaveBen SDD Senior Member Join Date: May 2005 Location: Ukiah, California Posts: 7,866 Thanks: 127 Thanked 505 Times in 488 Posts	FICMs go bad at about 120,000 miles, or so. You probably need a new FICM or at least a rebuilt one. I did the new Ford FICM in mine. Sorry, no quick fix after the CPS. Dave __________________ 2004 F-350 Regular cab with 6.0, Torqshift, 4X4, and just about all of the rest of the options. I added Guages, Satellite Radio, Air Horns, and a coolant filter. Bilstein shocks. Battery Desulphater that really works. Installed Jimmi Jammers. Pictures here: http://community.webshots.com/user/dbennett48 Completely Stock. I had a Detroit Diesel 8V92TA in a KW dump truck in 1980. That sucker would put out 425 hp but would never out pull a CAT.

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01-28-2012, 08:39 PM	#3
bismic1 SDD Member Join Date: Aug 2008 Location: Texas Posts: 92 Thanks: 2 Thanked 13 Times in 12 Posts	P1378 is for supply voltage IIRC (Logic Power). Check out the batteries and alternator. FYI: P1378: Low FICM logic power. System detects less than 7 volts. Could be low batteries, loose connections (or excessive circuit resistance), bad relay