User Manual

NexLink NL102PLUS User Manual
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2.2.2 DTCs for J1587/J1708 and J1939
This section explains the basic elements of fault codes for J1587/J1708 and
J1939 data bus protocols, how to view these codes on NL102P, and what they
mean. Each fault code on NL102P contain three distinct pieces of information,
as described below.
J1587/J1708 fault codes consist of the following, in this order:
 Subsystem Identifier (SID) – Indicates what function on the ECU has failed.
 Failure Mode Indicator (FMI) – Indicates in what way the function failed.
 Occurence (OC) – Indicates the occurence times of fault codes.
J1939 fault codes consist of the following, in this order:
 Suspect Parameter Number (SPN) – Indicates what function on the ECU
has failed.
 Failure Mode Indicator (FMI) – Indicates in what way the function failed.
 Occurence (OC) – Indicates the occurence times of fault codes.
2.3 J1708/J1587/J1939
SAE J1708, SAE J1587 and SAE J1939 are automotive diagnostic protocol
standard developed by the Society of Automotive Engineers (SAE).
SAE J1708
SAE J1708 is a standard used for serial communications between ECUs on a
heavy duty vehicle and also between a computer and the vehicle. With respect
to Open System Interconnection model (OSI), J1708 defines the physical layer.
Common higher layer protocols that operate on top of J1708 are SAE J1587
and SAE J1922.
SAE J1587
SAE J1587 is an automotive diagnostic protocol standard developed by the
Society of Automotive Engineers (SAE) for heavy-duty and most medium-duty
vehicles built after 1985. The J1587 protocol uses different diagnostic
connectors. Up to 1995, individual OEMs used their own connectors. From
1996 to 2001, the 6-pin Deutsch-connector was standard. Beginning in 2001,
most OEMs converted to the 9-pin Deutsch. Some OEMs still use the 6-pin
Deutsch. It has mostly been used for US made vehicles, and also by Volvo.