Decoding J1939 Message Identifiers When Extracting Data

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When extracting data from a PACCAR PX-8 or Cummins ISC engine, the following messages appeared on the J1939 CAN bus as documented on this page.

CAN ID PGN PGN Description Frequency Notes
0CF00300 61443 Electronic Engine Controller 2 0.05 Engine Data
0CF00400 61444 Electronic Engine Controller 1 0.02 Engine Data
10EF00FA   Proprietary A   All data were
43 00 00 00 00 00 02 FF
10EFFA00   Proprietary A   All data were
44 00 00 02 58 58 FF FF
18E0FF00   Cab Message 1 1.0 Broadcast: All data were
FF FF FF FF FF FF FF FF
18E0FF28   Cab Message 1 1.0 Broadcast: All data were
FF FF FF FF FF F0 FF FF
18EB00FA   Transport Protocol - Data Transfer Aperiodic There were 5 distinct time blocks of data. This is likely the data dump for PowerSpec
18EBFF00   Transport Protocol - Data Transfer 5 messages every 5 seconds These data were present before in previous logs
18EBFF0F   Transport Protocol - Data Transfer 5 messages every 5 seconds These data were present before in previous log
18EC00FA   Transport Protocol - Connection Management Aperiodic Only a couple bits change. This may be the tool requesting different data.
18ECFA00   Transport Protocol - Connection Management Aperiodic There were 5 distinct time blocks of data. This is likely the data dump for PowerSpec
18ECFF00   Transport Protocol - Connection Management 5.0 Broadcast: All data were
20 22 00 05 FF E3 FE 00
18ECFF0F   Transport Protocol - Connection Management 5.0 Broadcast: All data were
20 13 00 03 FF E1 FE 00
18EEFFFA   Address Claimed 2.0 First Message
86 68 54 01 00 80 00 00
Second Message
23 34 56 01 00 81 00 00

Each in blocks of 5 during the data dumps

18F0000F 61440 Electronic Retarder Controller 1 0.1 All data were
F0 7D 7D FF 0F FF FF FF
18F00100 61441 Electronic Brake Controller 1 0.1 All data were
FF FF FF CF 00 FF FF FF
18F0010B 61441 Electronic Brake Controller 1 0.1 All data were
CF FF F0 FF FF CD FF FF
18FD7C00 64892 Diesel Particulate Filter Control 1 0.5 All data were
F8 83 00 00 C3 0F E3 FF
18FDB300 64947 Aftertreatment 1 Outlet Gas 2 0.5 All data were
DA 24 FF FF FF FF FF FF
18FDB400 64948 Aftertreatment 1 Intake Gas 2 0.5 First Byte Changes
?? 25 FF FF FF FF FF FF
18FEBD00 65213 Fan Drive 1.0 All data were
00 F0 FF FF FF FF FF FF
18FEBF0B 65215 Wheel Speed Information 0.1 All data were
00 00 7D 7D 7D 7D FF FF
18FEC100 65217 High Resolution Vehicle Distance 1.0 All data were
A8 90 42 02 3F 93 42 02
18FECA00 65226 Active Diagnostic Trouble Codes 1.0 All data were
00 FF 00 00 00 00 FF FF
18FEDF00 65247 Electronic Engine Controller 3 0.02 All data were
84 A0 28 7D FB FF FF FF
18FEE000 65248 Vehicle Distance 0.1 All data were
9C 24 17 00 81 24 17 00
18FEEE00 65262 Engine Temperature 1 1.0 Third byte changes
62 FF ?? 29 FF FF FF FF
18FEEF00 65263 Engine Fluid Level/Pressure 1 0.5 All data were
FF FF FF 00 FE 7C FF FA
18FEF000 65264 Power Takeoff Information 0.1 All data were
FF FF FF E0 15 F0 CC FF
18FEF100 65265 Cruise Control/Vehicle Speed 0.1 All data were
FC 00 00 00 00 5D 00 00
18FEF200 65266 Fuel Economy (Liquid) 0.1 Fifth byte changes
00 00 00 00 7? 06 FF FF
18FEF500 65269 Ambient Conditions 1.0 All data were
C8 FF FF FF FF FF FF FF
18FEF600 65270 Inlet/Exhaust Conditions 1 0.5 All data were
FF 00 58 FF FF FF FF FF
18FEF700 65271 Vehicle Electrical Power 1 1.0 Fifth byte changes
FF FF FF FF F? 00 FF FF
18FEFF00 65279 Water in Fuel Indicator 10.0 All data were
FC FF FF FF FF FF FF FF
1CEBFA00   Transport Protocol - Data Transfer Aperiodic There were 5 distinct time blocks of data. This is likely the data dump for PowerSpec
1CEC00FA   Transport Protocol - Connection Management Aperiodic First Four bytes change
?? ?? ?? ?? FF 00 EF 00
1CECFA00   Transport Protocol - Connection Management Aperiodic First four bytes change
?? ?? ?? ?? FF 00 EF 00

The J1939 ID frame format is as follows:

J1939 Format

The Protocol Data Unit (PDU) bits describes the message format according to SAE J1939-21, Section 5.3 and can contain two groups. PDU1 are from 0 to 239 (0x00 to 0xEF) and PDU2 are from 240 to 255 (0xF0 to 0xFF). Messages that have PDU1 format make use of the destination and source address structure of the J1939 message ID. Messages in PDU2 format are intended to be broadcast on the network and use a group extension expand the possibilities on the network.

The highlighted messages are analyzed below:

18EC00FA

J1939 Message ID Structure for 18EC00FA
J1939 Frame Format Priority EDP DP PDU Format (PF) PDU Specific (PS)
[Destination Address]
Source Address (SA)
Parameter Group Number
HEX 1 8 E C 0 0 F A
Decimal 1 8 236 0 250
60416
Binary 1 1 0 0 0 1 1 1 0 1 1 0 0 0 0 0 0 0 0 0 0 1 1 1 1 1 0 1 0
CAN 29 Bit ID Pos. 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

Key Parameters:

Name:

Transport Protocol - Connection Management

Description:

Used for the transfer of Parameter Groups that have 9 or more bytes of data.

Timing:

Aperiodic

 

18EB00FA

J1939 Message ID Structure for 18EB00FA
J1939 Frame Format Priority EDP DP PDU Format (PF) PDU Specific (PS)
[Destination Address]
Source Address (SA)
Parameter Group Number
HEX 1 8 E B 0 0 F A
Decimal 1 8 235 0 250
60160
Binary 1 1 0 0 0 1 1 1 0 1 0 1 1 0 0 0 0 0 0 0 0 1 1 1 1 1 0 1 0
CAN 29 Bit ID Pos. 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

Key Parameters:

Name:

Transport Protocol - Data Transfer

Description:

Used for the transfer of data associated with Parameter Groups that have more than 8 bytes of data.

Timing:

Aperiodic

Notes:

The source address is FA and the destination address is 00. It is likely that the source address of FA corresponds to the Nexiq USB-Link device.

The message 18EFA00 is likely sending messages from the engine controller to the Nexiq.

 

18EEFFFA

J1939 Message ID Structure for 18EEFFFA
J1939 Frame Format Priority EDP DP PDU Format (PF) PDU Specific (PS)
[Destination Address]
Source Address (SA)
Parameter Group Number
HEX 1 8 E E F F F A
Decimal 1 8 238 255 250
61183
Binary 1 1 0 0 0 1 1 1 0 1 1 1 0 1 1 1 1 1 1 1 1 1 1 1 1 1 0 1 0
CAN 29 Bit ID Pos. 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

Key Parameters:

Name:

Address Claimed

Description:

Message used to claim an address for a Controller Application.

Timing:

Aperiodic

Notes:

The source address is FA and the destination address is FF. It is likely that the source address of FA corresponds to the Nexiq USB-Link device and the destination address is to all (i.e. a broadcast message).

1CEBFA00

J1939 Message ID Structure for 1CEBFA00
J1939 Frame Format Priority EDP DP PDU Format (PF) PDU Specific (PS)
[Destination Address]
Source Address (SA)
Parameter Group Number
HEX 1 C E B F A 0 0
Decimal 1 C 235 250 0
60410
Binary 1 1 1 0 0 1 1 1 0 1 0 1 1 1 1 1 1 1 0 1 0 0 0 0 0 0 0 0 0
CAN 29 Bit ID Pos. 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

Key Parameters:

Name:

Transport Protocol - Data Transfer

Description:

Used for the transfer of data associated with Parameter Groups that have more than 8 bytes of data.

Timing:

Aperiodic

Notes:

The source address is 00 (likely the engine controller) and the destination address is 250 (likely the Nexiq). These are the lowest priority messages and the data from ECM is being transferred with these IDs.

Transport Protocols

Section 5.10 of SAEJ1939-21 discusses how messages are transmitted over the CAN network if they are larger than 8 bytes. Each message will have a sequence number and 7 bytes of data. The last message in the sequence will transmit FF for each unused byte.