COMMUNICATION PROTOCOLS (CONT’D)

Physical Layer

General

The physical layer and physical signaling of the external test equipment shall be in accordance with ISO 11898-1 and ISO 11898-2, with the following restriction.

Baud rate

Nominal bit rate: 250kbps (500kbps is option)

CAN bit timing

Sample Point = 75% tsync = 1tp, TSEG1 = (7+4)tp , TSEG2 = 4tp

Message Format

J1939-71 Application Layer

[See "APPENDIX B: MESSAGE FORMAT (J1939-71, -73, -21)" on page 20-60-1]

MESSAGE FORMAT (CONT’D)

J1939-71 Application Layer (Cont’d) pgn65188 - Engine Temperature #2 - ET2 -

MESSAGE FORMAT (CONT’D)

J1939-71 Application Layer (Cont’d) pgn65259

MESSAGE FORMAT (CONT’D)

J1939-71 Application Layer (Cont’d) pgn65269 - Ambient Conditions - AMB - pgn65271 - Vehicle Electrical Power - VEP - pgn56320 - Anti-theft Status - ATS -

Transmission Repetition Rate: This message is transmitted in response to an Anti-Theft Request message. This message is also sent when the component abnormal power interruption. In this situation the Anti-Theft Status Report is sent without the Anti-Theft Request.

NOTE:See Figure [Figure 20-30-1] for examples of Anti-theft message transfers. Bit 1 is the right most bit in each byte.

MESSAGE FORMAT (CONT’D)

J1939-71 Application Layer (Cont’d) pgn56576 - Anti-theft Request - ATR -

Transmission Repetition Rate: Transmission of this message is interrupt driven. This message is also transmitted upon power-up of the interfacing device this message.

NOTE:See [Figure 20-30-1] for examples of Anti-theft message transfers. Bit 1 is the right most bit in each byte. For further details the reader is referred to our Development Dept.<R,1,1>

MESSAGE FORMAT (CONT’D)

J1939-71 Application Layer (Cont’d)

Figure 20-30-1

Immobilizer unit

PGN 56320: The E-ECU provides an Anti-Theft Status Report (request Not_valid, appropriate lock status, password valid=false, seed present=false)

Byte1:

E-ECU 11 ** 0000

Byte 2-8: Blank zero

PGN 56576: This is a request for an encryption seed

Byte1: 011 ** 00 *

Byte 2-8: Blank zero

PGN 56320: E-ECU provides the encryption seed

Byte1: ****** 01

Byte 2-8: Encryption seed

PGN 56576: Sends the operator's password (that was entered with the intention to Unlock the E-ECU)

Byte1: 011 ** 01 *

Byte 2-8: Encryption password

PGN 56320: E-ECU provides feedback if the password entered by the operator is a valid password and if the Unlock command was successfully executed

Byte1: 00 ** 01 ** 021756-00E

Byte 2-8: Blank zeros