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
|
| 10EFFA00 |
|
Proprietary A |
|
All data were
|
| 18E0FF00 |
|
Cab Message 1 |
1.0 |
Broadcast: All data were
|
| 18E0FF28 |
|
Cab Message 1 |
1.0 |
Broadcast: All data were
|
| 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
|
| 18ECFF0F |
|
Transport Protocol - Connection Management |
5.0 |
Broadcast: All data were
|
| 18EEFFFA |
|
Address Claimed |
2.0 |
First Message
Second Message
Each in blocks of 5 during the data dumps
|
| 18F0000F |
61440 |
Electronic Retarder Controller 1 |
0.1 |
All data were
|
| 18F00100 |
61441 |
Electronic Brake Controller 1 |
0.1 |
All data were
|
| 18F0010B |
61441 |
Electronic Brake Controller 1 |
0.1 |
All data were
|
| 18FD7C00 |
64892 |
Diesel Particulate Filter Control 1 |
0.5 |
All data were
|
| 18FDB300 |
64947 |
Aftertreatment 1 Outlet Gas 2 |
0.5 |
All data were
|
| 18FDB400 |
64948 |
Aftertreatment 1 Intake Gas 2 |
0.5 |
First Byte Changes
|
| 18FEBD00 |
65213 |
Fan Drive |
1.0 |
All data were
|
| 18FEBF0B |
65215 |
Wheel Speed Information |
0.1 |
All data were
|
| 18FEC100 |
65217 |
High Resolution Vehicle Distance |
1.0 |
All data were
|
| 18FECA00 |
65226 |
Active Diagnostic Trouble Codes |
1.0 |
All data were
|
| 18FEDF00 |
65247 |
Electronic Engine Controller 3 |
0.02 |
All data were
|
| 18FEE000 |
65248 |
Vehicle Distance |
0.1 |
All data were
|
| 18FEEE00 |
65262 |
Engine Temperature 1 |
1.0 |
Third byte changes
|
| 18FEEF00 |
65263 |
Engine Fluid Level/Pressure 1 |
0.5 |
All data were
|
| 18FEF000 |
65264 |
Power Takeoff Information |
0.1 |
All data were
|
| 18FEF100 |
65265 |
Cruise Control/Vehicle Speed |
0.1 |
All data were
|
| 18FEF200 |
65266 |
Fuel Economy (Liquid) |
0.1 |
Fifth byte changes
|
| 18FEF500 |
65269 |
Ambient Conditions |
1.0 |
All data were
|
| 18FEF600 |
65270 |
Inlet/Exhaust Conditions 1 |
0.5 |
All data were
|
| 18FEF700 |
65271 |
Vehicle Electrical Power 1 |
1.0 |
Fifth byte changes
|
| 18FEFF00 |
65279 |
Water in Fuel Indicator |
10.0 |
All data were
|
| 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
|
| 1CECFA00 |
|
Transport Protocol - Connection Management |
Aperiodic |
First four bytes change
|
The J1939 ID frame format is as follows:
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.
