5036989 JOHNSON CLAMP, SWITCH LEAD

control
Fast idle control
Idle speed control
PTO operation
Vehicle speed limiting
Speedometer
Progressive shift
Idle shutdown
Operation of the air inlet heater
Secure idle theft deterrent
Trip data
Maintenance dataThere are three different methods that can be used to obtain the information for the ECM to use for calculating vehicle speed. The ECM can calculate vehicle speed by either of the following means:
The ECM monitors the signal from a vehicle speed sensor in pulses per kilometer (mile). The vehicle speed sensor is connected to the vehicle speed input circuit (terminals 32 and 33 of the ECM). This is the "Vehicle Speed Calibration" option.
The ECM receives a message over the J1939 data link from the transmission ECU that indicates revolutions per kilometer (mile) of the transmission output shaft. This is the "Vehicle Speed Cal (J1939-Trans)" option.
The ECM receives a message over the J1939 data link from the Anti-lock Brake System (ABS) that contains information about the wheel speed. This is the "Vehicle Speed Cal (J1939-ABS)" option.Each of these methods require a specific calibration number to be programmed into the ECM to calculate vehicle speed.For the "Vehicle Speed Calibration" option that uses the vehicle speed sensor, the ECM must know the number of pulses that are produced by the vehicle speed sensor during each kilometer (mile) of travel by the vehicle. In order to find the number of pulses that are produced by the sensor, multiply the tire size by the axle ratio. Multiply the number that was obtained in the previous calculation by the number of teeth on the output shaft that is used by the sensor to obtain the pulses.For the "Vehicle Speed Cal (J1939-Trans)" option, the ECM must know the number of times that the output shaft revolves per kilometer (mile) of travel by the vehicle. This can be calculated by one of the following methods:
Divide the pulses per kilometer (mile) of the sensor on the transmission output shaft by the number of teeth on the transmission output shaft.
Multiply the axle ratio by the number of revolutions per kilometer (mile) of the tire.For the "Vehicle Speed Cal (J1939-ABS)" option, the ECM must know a calibration number. The number is calculated by dividing the actual tire revolutions per kilometer (mile) by the tire revolutions per kilometer (mile) that is programmed into the ABS.The ECM calculates vehicle speed by converting the vehicle speed signal to kilometers per hour (km/h) or to miles per hour (mph). The conversion factor is customer programmable and the conversion factor is stored in pulses per km (PPKM) or pulses per mile (PPM).The variable for the tire revolution could be affected by changing from bias ply tires to radial tires and vice versa. Also, changing to radial tires that have a low profile could affect the variable for the tire revolution. This result may change the actual vehicle speed which could result in performance complaints or in complaints about fuel consumption. If the configuration of the tire has been changed, determine the new variable for the tire revolution. Enter the new value in pulses per km (PPKM) or in pulses per mile (PPM). The preferred method is obtaining the data from the individual tire manufacturers for the specific tire that is being used.Note: The ECM speedometer signal is set to 18,600 pulses per km (PPKM) or to 30,000 pulses per mile (PPM). For "GM Truck Manufacturer" configurations, the output of the speedometer is set to 2,485 PPKM (4,000 ppm). This setting cannot be changed. All speedometers that are driven by the ECM output (J1/P1 terminal 36 and terminal 37) must match the fixed output of the ECM for proper operation.
Use Caterpillar Electronic Technician (ET) to Determine the Configuration for the Vehicle Speed Input to the ECM.
Establish communication between the Caterpillar Electronic Technician (ET) and the ECM.
Access the "Configuration Parameter List". View the "Vehicle Speed Parameters". Determine if the vehicle is configured to use the "Vehicle Speed Calibration" option, the "Vehicle Speed Cal (J1939-Trans)" option, or the "Vehicle Speed Cal (J1939-ABS)" option. Proceed to Test Step 2 if the vehicle is configured to use the "Vehicle Speed Calibration" option.Proceed to Test Step 3 if the vehicle is configured to use the "Vehicle Speed Cal (J1939-Trans)" option.Proceed to Test Step 4 if the vehicle is configured to use the "Vehicle Speed Cal (J1939-ABS)" option.
Calculate Pulses Per Kilometer (Mile)