SUPPORT 2394378 - Caterpillar

System Operation Description:Power Train Data LinksPower train data links are designed to facilitate communication and control between electronically controlled Anti-Lock Brakes (ABS), traction control systems, transmissions, and engines. Typical control would include a momentary reduction of engine rpm and/or of engine torque, that is triggered by a signal from an off-engine control module such as the ABS, the traction control, or the transmission. An off-engine control module is a control module that is not part of the Caterpillar engine control system.Any combination of the following systems may be installed together on a vehicle:
Traction control
Transmission control
ABSThe required components are installed at the OEM when the vehicle is built.Wiring for the power train data link, off-engine control modules, and wiring are installed by the vehicle OEM. Questions that are related to the configuration of the hardware, software, and installation should be directed to the vehicle OEM.The following two power train data links are available:
SAE J1922
SAE J1939The J1922 and J1939 refers to the standard for data link communications of the Society of Automotive Engineers. The ECM has a customer programmable parameter that is called "Powertrain Data Link" which can be programmed to any one of the following options:
J1922
J1939
J1922 and J1939
NoneAnti-Lock Brake Systems (ABS)The "Powertrain Data Link" may be used by an ABS in order to disable the engine retarder when the control system for the ABS determines that the engine retarder should be disabled. This is usually achieved when the ABS is activated.Traction Control SystemsLoss of traction is determined by sensors on the vehicle that are mounted near the wheels. These sensors are also used by the ABS. Typically, a system with traction control includes anti-lock brakes.
Illustration 1 g01072392
Typical configurationTransmission ControlThe following characteristics are determined by a vehicle speed sensor in the transmission:
Transmission shift points
Engine rpm
LoadThe sensors for power train control provide signals to the vehicle control module of the "Powertrain Data Link". The vehicle control module of the "Powertrain Data Link" then communicates with the ECM. The ECM receives a request from the "Powertrain Data Link". The ECM responds by momentarily limiting the following characteristics:
Engine rpm
Torque
Both engine rpm and torqueThe presence of an active J1922 data link circuit can be determined by observing the "Powertrain Status" screen on the Caterpillar Electronic Technician (ET). The status screen will display "Installed" if the proper software is installed in the ECM, and there is no action that is being requested at that time by any of the control modules on the data link.If an action is being requested by one of the vehicle control modules, the display will indicate the control that is making the request (traction control or transmission control) or a combination of the two. Power train control is also displayed in the upper right hand corner of the display status screen. This space is replaced by the low oil pressure indicator, when a condition of low oil pressure exists.J1922 Data LinkSAE J1922 is standard with all software.Note: The circuit for the J1922 data link must be twisted pair wiring. Twisted pair