User manual

144 of 148
J1939 DIAGNOSTIC TROUBLE CODES
Active DTC parameters will be updated and synchronized with front panel GSC400 display.
Previously active DTC parameters will remain active even after they are read from the
registers. Parameters can only be cleared once power is cycled to GSC400 controller or a
shutdown is initiated.
(Note: In one byte,Bit7 is MSB,Bit0 is LSB )
40114
Active DTC lamp
status and reserved
lamp status
0~65536
R
The High byte of 40114 holding
register
Bit 7~6 malfunction indicate lamp
status
Bit 5~4 red stop lamp status
Bit 3~2 amber warning lamp status
Bit 1~0 protect lamp status
Low byte reserved for lamp status
40115
Active DTC No. 1
(Each DTC code will
be stored in 2 holding
register, High Byte of
the first register is
Byte 1, Low byte is
byte 2, high byte of
second register is
byte 3, Low Byte is
Byte 4). See right
column for more
information.
0~65536
R
(DTC was defined in SAE J1939-73)
UCMU: Bit7 of Byte 4. SPN Conversion
Method bit. If CM = 0 below applies,
else see below the table.
SPN: SPN is 19 bits value, the MSB
of SPN is spn18, and the LSB of SPN
is spn0. Data range is from 0 to
524,287. Bit7~Bit5 of the byte 3 is
spn18~spn16, Bit7~Bit0 of the byte 2
is spn15~spn8, and the Bit7~Bit0 of
byte 1 is spn7~spn0.
FMI: FMI is 5 bits value; data range is
from 0 to 31. It is the Bit4~Bit0 of byte
3.
OC: OC is 7 bits value; data range is
from 0 to 126. It is the Bit6~Bit0 of the
byte 4.
40116
0~65536
R
40117 ~
40126
Registers 40117 to 40126 not shown. They
contain Active DTC No. 2 to 6 and are in the
same format as above.
40180
Previous Active DTC
lamp status and
0~65536
R
Bit 8~7 malfunction indicate lamp
status
Bit 6~5 red stop lamp status