Oshkosh JLG 1500SJ, Service And Maintenance Manual, Page: 197 / 706

SECTION 3 - CHASSIS & TURNTABLE
3121262 – JLG Lift – 3-147
Diagnostic Trouble Codes
The numeric diagnostic trouble codes assigned to the faults in
this section are cross-referenced to SAE’s "Recommended
Practice for Diagnostic Trouble Code Definitions" (SAE J2012).
While these codes are recommended, the manufacturer may
define their own codes by assigning a new number to the flash
code in the diagnostic calibration. This will assign both the
DTC as displayed in EDIS as well as the flash code output on
the MIL output pin. EDIS may be used to connect to the DGC
ECM via CAN.
CAN
The DGC supports SAE J1939 CAN based diagnostic support.
This includes:
• DM1: Active Diagnostic Trouble Codes
• DM2: Previously Active Diagnostic Trouble Codes
• DM3: Diagnostic Data Clear/Reset of Previously Active
DTCs
• DM4: Freeze Frame Parameters
• DM5: Diagnostic Readiness (bytes 1, 2, and 3 are sup-
ported)
• DM11: Diagnostic Data Clear/Reset For Active DTCs
• DM12: Emissions-Related Active Diagnostic Trouble Codes
• DM19: Calibration Information
All diagnostic trouble codes broadcast over CAN will be SAE
J1939 DM1 and DM2 formatted messages. DGC ECMs are com-
pliant with J1939 OBD-M, supporting the Diagnostic Messages
above as well as user indicators and CAN data defined in the
OBD-M protocol. Faults available for broadcast and their
respective SPN/FMI numbers are dependent on the applica-
tion and engine calibration. There are 4 CAN SPN/FMI lists
available in the DGC software set, contact EControls Inc. for a
list of CAN SPN/FMIs.
The data capture at the occurrence of a fault, known in the
ECM as fault snapshot (FSS), is available upon DM4 request.
The following bytes are supported for DM4 if configured in the
ECM software:
• Byte 1: Freeze Frame Length
• Byte 2-6: SPN, FMI, SPN Conversion Method, and Occur-
rence
• Byte 7: Manifold Absolute Pressure
• Byte 8-9: Engine Speed
• Byte 10: Engine Load (MAP based estimate)
• Byte 11: Engine Coolant Temperature
• Byte 14: # of starts since fault was last active
• Byte 15: Index into FSS_storage table for Fault Snap Shot
retrieval
Resetting active and previously active DTCs is handled
through DM11 and DM3, respectively DM1 and DM2 lamp
indicators are assigned to each fault based on the fault.s diag-
nostic action as defined in the calibration. The lamps are
assigned based on the configuration outlined in Table 3-6.
MIL Output
The MIL output is used to convey fault information to the
equipment operator. The MIL is always on (grounded) when
the system is in a key-on (Vsw), engine-off state. This provides
assurance that the output is functional. If a DTC is logged as
previously-active (historic), the MIL will send a single flash for
the “Blink on-time” every “Blink off-time.”
Table 3-6. J1939 Diagnostic Lamp Configuration
ECI DIAGNOSTIC ACTION J1939 LAMP
MIL MIL
Soft Warning Amber
Hard Warning, Low Rev Limit, Shutdown Red Stop
Power Derate 1 & 2 Protect
Forced Idle
None (use in combination with other
action)