JLG 1350SJP Service Manual - Manual (Page 208)

SECTION 3 - CHASSIS & TURNTABLE
3-162 – JLG Lift – 3121142
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 audible
warning or illuminate secondary warning lamp, disable
adaptive fueling correction for remainder of key cycle, rec-
ommend power derate 2 and low rev limit to reduce possi-
ble engine damage and/or overspeed condition
• Non-emissions related fault
Random Access Memory is located within the microprocessor
and can be read from or written to at any time. Data stored in
RAM include DTCs (when fault configuration is set to "Battery
Power Retained"), adaptive fuel learn tables, octane adapta-
tion table, misfire adaption tables, and closed loop fuel multi-
pliers. 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.
RAM
ECM
Microprocessor