Service Manual Manual

SECTION 3 - CHASSIS & TURNTABLE
3-182 – JLG Lift – 3120788
DTC 604- Microprocessor Failure - RAM
• Engine Control Module- Random Access Memory
• Check Condition- Key on
• Fault Condition- Internal ECM microprocessor memory
access failure
• Corrective Action(s)- Illuminate MIL and/or sound audi-
ble warning or illuminate secondary warning lamp, dis-
able adaptive fueling correction for remainder of key
cycle, recommend power derate 2 and low rev limit to
reduce possible engine damage and/or overspeed
condition
• Non-emissions related fault
Random Access Memory is located within the micropro-
cessor and can be read from or written to at any time.
Data stored in RAM include DTCs (when fault configura-
tion is set to "Battery Power Retained"), adaptive fuel learn
tables, octane adaptation table, misfire adaption tables,
and closed loop fuel multipliers. The ECM has checks that
must be satisfied each time an instruction is executed.
This fault will set if the ECM detects a problem accessing
or writing information to RAM and should be configured to
set a power derate 2 and low rev limit to reduce possible
engine damage and reduce possibility of an overspeed
condition. If this fault sets, the ECM will reset itself and log
the code. This fault should be erased by a technician after
diagnostics are performed. The fault should be configured
to never forget and will not self-erase.