Referencing an old thread:



I have a 2004 6.0 and have had various FICM issues in the past. All have been easily fixed using the online repair (first couple of times) and using Ed at ficmrepair.com more recently.

I currently am running on 7 cylinders and the ficm is putting out some crazy voltages (read by SCANGAUGE 2).

FICM Vehicle Power, should be 12V, shows 192V
FICM Logic Power, should be 12V, shows 192V
FICM Main Power, should be 48V, shows 120V.

Anyone ever seen this before? Once I noticed this, I sent the FICM into Ed and he stated it was a 1 in 200 or 1 in 300 issue, very rare. He repaired the damaged board (excellent service and support as always) and was very fair on price. I then put it back in the truck and within seconds had the same problem. May not have fried the board though, just still running on 7 and outputting the crazy voltages.

Ed had me check several things, I did most of the items below.

(1) Most likely cause was alternator, I had mine bench tested several places, all tested good. 140Amp FORD version, replaced voltage regulator anyway to be safe.

(2) Second most likely cause was FICM input power harness (The "C" connector). I should have checked harder into this, but electrical problems are a little outside of my capabilities sometimes. I punted.

(3) Least likely of the three, but still worth checking was the batteries. I had both tested, one 3 year old battery tested just below the spec... ~600CCA, so I replaced it. Other battery was only 6 months old and tested ~900CCA. Together that is plenty of CCA so I doubt it had anything to do with the damage. Also, it seems more likely this would have caused the more classic low voltage in the 48V circuit, not the crazy high Volts.

If anyone has seen such before, I'm in need of some ideas to limit my search.

Thanks!
Brian

 

This is the thread I tried to link as a reference.

https://www.ford-trucks.com/forums/1...m-voltage.html

 

Crazy would be exact, am I missing something here? 19.2 volt instead of 192 volts?

 

If the alternators rectifier is toast, it would do that... feeds the truck a higher voltage. Check that.

 

Not an electrical here, I had the voltage regulator on the output of the alternator replaced. Is this the same thing as the "rectifier" mentioned?

On the voltage, It reads 192, not 19.2. I double and triple checked my programming of the variables in the scan-gauge. I also verified from multiple online sources that the programming was correct.

 

Also, this might be relevant, I checked with Key on (never started) and I can see the high voltages without the alternator running. Again, not an electrical guy.

 

I would find another way to test the FICM voltage. Either another obd tool or check it direct with volt meter. Do any of your buddies have a 6.0? If so plugged your SG II into there truck. My guess is yours SG II is buggered up. Have you had it checked for codes?

 

The only two places in the truck that could make voltage are
The Alternator and the FICM. Well there are other things but
they are all so small in the amount that we won't count them.
A defective diode rectifier can pass on some very high voltages.
But you said Key O Engine Off and that points at the SGII being
a issue.



Sean <BR>

6.0L Tech Folder

 

SGII is bad. I probed the 48V pin on the access port of the FICM this morning and Key-on produced 48.5V. SGII showed over 100V.

Now I'm chasing an injector harness issue or a failed injector.... I'm going to get another gauge to determine which cylinder is misfiring and go from there.

Thanks for the help.

 

Been said already but you need to verify the SGII on some other vehicle.
The PCM could also be having issues.


Sean <BR>

6.0L Tech Folder