6 COMMUNICATION PROTOCOLS - Wanderlodge Gurus

1 DDEC IV ON-HIGHWAY - EGR APPLICATION AND INSTALLATION6 COMMUNICATION OVERVIEW .. SAE J1587 .. SAE J1922 .. SAE J1939 .. 6-45 All information subject to change without notice.(Rev. 3/05)6-17SA7430503 Copyright 2005 DETROIT DIESEL CORPORATIONCOMMUNICATION PROTOCOLSTHIS PAGE INTENTIONALLY LEFT BLANK6-2 All information subject to change without notice.(Rev. 3/05)7SA743 0503 Copyright 2005 DETROIT DIESEL CORPORATIONDDEC IV ON-HIGHWAY - EGR APPLICATION AND components of the DDEC IV system are the serial COMMUNICATION links SAE J1587, SAEJ1922, and SAE J1939.

2 Using these COMMUNICATION links allows DDEC IV to offer the followingfunctionality:Transmitting sensor information from the ECM via the data link at regular intervals and/orupon request to obtain data and to monitor for failuresSharing information between stand-alone modules used in the system via the data linkSharing engine data with electronic dashboard displays and vehicle managementinformation systems via the data linkTransmitting and performing diagnostic procedures from external instrumentation such asthe hand-held diagnostic data readers or DDDL via the data linkTransmitting customer requested changes to the ECM from external instrumentation viathe data linkTransmitting to the

3 Powertrain the messages assigned to both the engine and thetransmission following industry standard Society of Automotive Engineers (SAE) documents can beused as a reference:SAE J1587,Electronic Data Interchange Between Microcomputer Systems In HeavyDuty Vehicle ApplicationsSAE J1708,Serial Data Communications Between Microcomputer Systems In HeavyDuty Vehicle ApplicationsSAE J1922,Powertrain Control Interface For Electronic Controls Used In Medium AndHeavy Duty Diesel On-highway Vehicle ApplicationsSAE J1939/71,Vehicle Application LayerSAE J1939,Top Layer (Overview)SAE J1939/01,Truck and Bus ApplicationsSAE J1939/11,Physical LayerSAE J1939/21,Data Link LayerSAE J1939/73,Application Layer DiagnosticsTo obtain a copy of the above documents contact the Society of Automotive Engineers (SAE).

4 SAE International400 Commonwealth DriveWarrendale, PA 15096 Attention: PublicationsPhone: (412) information subject to change without notice.(Rev. 3/05)6-37SA7430503 Copyright 2005 DETROIT DIESEL CORPORATIONCOMMUNICATION PROTOCOLSTHIS PAGE INTENTIONALLY LEFT BLANK6-4 All information subject to change without notice.(Rev. 3/05)7SA743 0503 Copyright 2005 DETROIT DIESEL CORPORATIONDDEC IV ON-HIGHWAY - EGR APPLICATION AND J1587 SAE RP J1587 defines the recommended format of messages and data being communicatedbetween microprocessors used in heavy-duty vehicle applications. Circuits 900 (Data Link +)and 901 (Data Link -) as shown on the Vehicle Interface Harness schematic are used as theJ1587 COMMUNICATION link.

5 These circuits also exist in the DDEC six-pin diagnostic connectorfor use with the :ThemaximumlengthfortheSAEJ1587 DataLinkis40m(130ft). FORMATA complete description of the DDEC IV parameters is provided within this section of the IV transmits parametric data at SAE J1587recommended rates in packed message first byte or character of each message is the Message Identification character (MID). TheMID identifies which microcomputer on the serial COMMUNICATION link originated the device in the system originating messages must have a unique MID. The assignment ofMIDs should be based on those listed in SAE RP J1587.

6 The primary MID for DDEC IV is with 12 and 16 cylinders use MID 128 and MID 175. Engines with 20 cylinders useMID 128, MID 175 and MID ProDriver display uses MID 171. Off-board diagnostic tools like hand-held readers shouldbe identified by MID 172. Off-board programming stations like Vehicle Engine ProgrammingStation (VEPS) should be identified by MID182. Messages using MIDsas recommended bySAE RP J1587 will be responded to by the also require identifiers. The subsystem identifier character (SID) is a single bytecharacter used to identify field-repairable orreplaceable subsystems for which failures can bedetected or isolated.

7 SIDs are used in conjunction with SAE standard diagnostic codes defined inJ1587 within identifiers used by DDEC are defined and listed in Table Mode Identifier (FMI)The FMI describes the type of failure detected in thesubsystem and identified by the PID or Identification Character (MID)The MID is the first byte or character of eachmessage that identifies which microcomputer onDDEC 1587 serial COMMUNICATION link originatedthe Identification Character (PID)A PID is a single byte character used in DDEC 1587messages to identify the data byte(s) that identify the parameters Identification Character (SID)A SID is a single byte character used to identifyfield-repairable or replaceable subsystems for 6-1 Identifiers Used by DDECAll information subject to change without notice.

8 (Rev. 3/05)6-57SA7430503 Copyright 2005 DETROIT DIESEL CORPORATIONCOMMUNICATION MESSAGE PRIORITYEach message sent by DDEC is assigned a priority on a scale of 1 to 8, in compliance with themessage priority assignment specified in SAE RP J1708. The most critical message has a priorityof one. The message assignments are listed in Table6-2. All devices transmitting messages acrossDDEC's 1708/1587 Data Link must be prioritized and transmitted in this and 2 Reserved for messages that require immediate access to the and 4 Reserved for messages that require prompt access to the busin order to prevent severe mechanical and 6 Reserved for messages that directly affect the economicalor efficient operation of the and 8 All other messages not fitting into the previous priority 6-2 Message Priority AssignmentsSAE J1587 Parameters Available with DDEC IVDDEC IV supports the J1587 parameter identifiers (PIDs)

9 Listed in Table 6-3 andlisted in Table :Data is transmitted only if the source has been configured for the Fuel Economy Natural Gas248 Total VSG Hours148 Instantaneous Fuel Economy Natural Gas249 Total Engine Revolution149 Mass Flow Rate Natural Gas250 Total Fuel Used229 TotalFuelUsed NaturalGas251 Clock230 TotalIdleFuelUsed NaturalGas252 Date231 Trip Fuel Natural Gas351 Turbo Compressor Inlet Temperature243 Device Identification354 Relative Humidity244 Trip Miles404 Turbo Compressor Out Temperature245To t a l M i l e s411 EGR Differential Pressure247 Total Engine Hours412 EGR Temperature 439 Extended Range Boost PressureTable 6-3

10 SAE J1587 PIDs Provided by DDEC IV6-6 All information subject to change without notice.(Rev. 3/05)7SA743 0503 Copyright 2005 DETROIT DIESEL CORPORATIONDDEC IV ON-HIGHWAY - EGR APPLICATION AND INSTALLATIONPIDD escriptionPIDD escription 109 Coolant Pressure18 Extended Range Fuel Pressure110 Coolant Temperature19 Extended Range Oil Pressure111 Coolant Level20 Extended Range Coolant Pressure113 Engine Governor Droop44 Attention/Warning Indicator Lamps Status121 Engine Retarder Status48 Extended Range Barometric Pressure122 Engine Retarder Percent51 Throttle Position153 High Range Crankcase Pressure52 Engine Intercooler Temperature154 Auxiliary Input & Output Status #262 Retarder Inhibit Status155