JLG 1200SJP Service Maintenance Manual page 218

SECTION 3 - CHASSIS & TURNTABLE
SFC 556- RTI 3 Loss
Key On - Engine Running
System Data Mode
Clear System Fault
Does SFC 556 reset
with engine idling?
No
Fault is intermittent
3-172
Check all power and
ground circuits to ECM
Yes
Are all circuits ok?
No
Repair wiring to
ECM and retest
– JLG Lift –
Yes
Replace ECM with known
good part and retest
3121142