Mid 144 Sid 231 Sae J1939 Control Link; Fault Codes - Volvo TSI Manual

Group 28

MID 144 SID 231 SAE J1939 Control Link

High-speed digital communication between different electronic control units takes place
over the J1939 Control Link; this is used to control vehicle operation. If the J1939 Con-
trol Link fails, the J1587/1708 Information Link serves as a "back-up" control link.
•
Text Messages
In vehicles equipped with diagnostic display, the fol-
lowing message(s) will appear:
•
Instrument Cluster Graphics Display (VN):
SAE J1939 data link
•
Data Link Instrument Cluster (WG, AC, WX):
The Data Link instrument cluster graphics display
used on WG-, AC-, and WX-series vehicles can
display a limited number of text messages. For infor-
mation, see "Data Link Instrumentation," Volvo
Service Publication PV776–381–620SM.
•
VCADS Pro Display:
SAE J1939 data link

Fault Codes

FMI 2
Intermittent or incorrect data.
Conditions for fault code:
•
If the VECU does not receive confirmation for the
messages on the J1939 Control Link, the VECU in-
terprets this as a fault and an fault code is set.
Possible cause:
•
Loose connection.
•
Open circuit in J1939 Control Link wire.
•
Switch resistance and oxidation.
Reaction from the VECU:
•
Fault code is set.
•
Yellow lamp is requested.
Noticeable external symptom:
•
Yellow lamp lights up.
FMI 12
Faulty unit or component.
Conditions for fault code:
•
If the expected messages are not available from a
control unit on the J1939 Control Link, the VECU in-
terprets this as a fault and an fault code is set.
Possible cause:
•
Open circuit in J1939 Control Link wire.
•
Switch resistance and oxidation.
Reaction from the VECU:
•
Fault code is set.
•
Yellow lamp is requested.
Noticeable external symptom:
•
Yellow lamp lights up.
Troubleshooting
231