Early-build 2004 Randomly Losing FICM_SYNC

mchan68 · April 9, 2011

Why does all the bullshit have to happen on a Friday afternoon? I got one here, that stalls randomly due to losing FICM_SYNC. There was a later caibration update for the PCM (3U7A-12A650-FTH). During attempt to reprogram, the PCM and TCM took, but the FICM portion failed. This vehicle appears to have the original FICM in it. FICM_M voltage at 48.5 volts under all conditions? Anyone else ever seen one like this before? If so, what was the repair? When the concern happens, it sets a U0105.

joshbuys · April 9, 2011

FICM_SYNC indicates the FICM is receiving cmp/ckp data from the PCM. If FICM_SYNC is dropping out, but SYNC still says yes, I would suspect a harness issue. Try wiggling the harnes near the FICM on top of the intake manifold, press it down against the manifold. I've seen several where the harness was chaffed and if pressed against the manifold would shut the engine off.

Mikill · April 11, 2011

^^^^What he said and also check the connectors on the drivers side for any loose connections.

mchan68 · April 11, 2011

A new FICM it is, for the win!!! 49.5 FICM_M voltage on the new FICM to boot!!! This one was particularly difficult for me to condemn the FICM due to FICM_M, L and V voltages that were within specs even during the concern. After some wiggling and close inspection of wiring, unable to recreate the symptom, I remembered having a tester to plug in. Sure enough plugging in the tester caused the symptom to disappear. I just find it odd that that code sets is when the FICM just goes off line, but yet I can still read voltages. Oh well, live and learn I guess.