JLG 450A_AJ Series II Service Manual - Manual (Page 194)

SECTION 3 - CHASSIS & TURNTABLE
3-154 – JLG Lift – 3121290
SFC 556- RTI 3 Loss
Key On - Engine Running
System Data Mode
Clear System Fault
Does SFC 556 reset
with engine idling?
Fault is intermittent
Replace ECM with known
good part and retest
No
Check all power and
ground circuits to ECM
Are all circuits ok?
Repair wiring to
ECM and retest
Yes
Yes
No