825267 Mercury RETAINER-REED

Test Step 1. Use the Caterpillar Electronic Technician (ET) to Determine the Configuration for the Vehicle Speed Input to the ECM
Ensure that the keyswitch is in the OFF position.
Connect Cat ET to the cab data link connector.
Access the "Configuration Parameter List". Determine the "Vehicle Speed Parameters" that is currently used by the ECM. Expected Result:The ECM is configured to one of the following options:"Vehicle Speed Calibration" "Vehicle Speed Cal (J1939-Trans)""Vehicle Speed Cal (J1939-ABS)"Results:
"Vehicle Speed Calibration" - The ECM is configured for the "Vehicle Speed Calibration" option. Proceed to Test Step 2.
"Vehicle Speed Cal (J1939-Trans)" - The ECM is configured to use the "Vehicle Speed Cal (J1939-Trans)" option. Proceed to Test Step 3.
"Vehicle Speed Cal (J1939-ABS)" - The ECM is configured to use the "Vehicle Speed Cal (J1939-ABS)" option. Proceed to Test Step 4.Test Step 2. Calculate Pulses Per Kilometer (Mile)
Calculate pulses per kilometer (PPKM) or pulses per mile (PPM). PPKM = K X Ra X N.PPM = M X Ra X N.K - This symbol represents the tire revolution per kilometer. This is a constant that is divided by the tire's load radius (static).M - This symbol represents the tire revolutions per mile. This is a constant that is divided by the tire's load radius (static).Ra - This symbol represents the rear axle ratio. The rear axle ratio can typically be found on the housing of the rear axle or on the specification sheet for the vehicle.N - This symbol represents the number of chopper teeth on the transmission drive shaft. The magnetic pickup sensor is mounted in order to generate a signal for each tooth that rotates past the sensor. The number of chopper teeth is usually 16. Some transmissions have 11 tooth chopper wheels.
Use Cat ET to enter pulses per km (PPKM) or pulses per mile (PPM) into the ECM. Expected Result:The value that is calculated is within the valid range of the ECM.Results:
OK - The ECM accepts the value that has been calculated. Once the value is entered, verify that the ECM is accurately measuring vehicle speed. Proceed to Test Step 5.
Not OK - The value that is calculated is not within the valid range of the ECM.Repair: The ECM will not accept the value that has been calculated. There is a problem with your calculation. Repeat this test step using careful calculations.STOPTest Step 3. Calculate the Revolutions Per Kilometer (Mile) of the Transmission Output Shaft
The correct value for the revolutions per kilometer (mile) of the transmission output shaft must be entered for the "Vehicle Speed Cal J1939-Trans" setting. If this value is unknown, either of the following calculations can be used to obtain the correct setting:
Divide the pulses per kilometer (mile) of the sensor on the transmission output shaft by the number of chopper teeth on the chopper wheel that is on transmission drive shaft.
Multiply the axle ratio by the number of revolutions per kilometer (mile) of the tire.
Use Cat ET to enter the calculated value into the ECM. Expected Result:The value is within the valid range of the ECM.Results:
OK - The ECM accepts the value that has been calculated. Once the value is entered, verify that the ECM is accurately measuring vehicle speed. Proceed to Test Step 5.
Not OK - The value that is calculated is not within the valid range of the ECM.Repair: The ECM will not accept the value that has been calculated. There is a problem with your calculation. Repeat this test step using careful calculations.STOPTest Step 4. Calculate the Tire Revolution Per Kilometer (Mile)
The correct calibration number must be entered for the "Vehicle Speed Cal J1939-ABS" setting. If this value is unknown, the following calculation can be used to obtain the correct setting. Divide the actual tire revolution per kilometer (mile) by the tire revolution per kilometer (mile) that is broadcast by theABS system.For example, the actual tire revolution per kilometer (mile) could equal 400 revolutions per kilometer (mile). The tire revolution per kilometer (mile) that is broadcast by the ABS system could equal 500 revolutions per kilometer (mile).The formula would be 400 / 500 = 0.800.Therefore, 0.800 would be the value that would be entered into the ECM for the actual tire revolution per kilometer (mile).
Use Cat ET to enter the calculated value into the ECM. Expected Result:This value is within the valid range of the ECM.Results:
OK - The ECM accepts the value that has been calculated. Once the value is entered, verify that the ECM is accurately measuring vehicle speed. Proceed to Test Step 5.
Not OK - The value that is calculated is not within the valid range of the ECM.Repair: The ECM will not accept the value that has been calculated. There is a problem with your calculation. Repeat this test step using careful calculations.STOPTest Step 5. Check the Speedometer CalibrationDetermine the speedometer's vehicle speed calibration setting.Note: The ECM can only provide a signal at 18,600 pulses per kilometer (30,000 pulses per mile).Expected Result:The speedometer is calibrated to 18,600 pulses per kilometer (30,000 pulses per mile).Results:
OK - The speedometer is correctly calibrated.Repair: Once the value is confirmed, verify that the speedometer is accurately reporting the vehicle speed.STOP
Not OK - Repair: Reprogram the speedometer to the correct setting for the pulses per kilometer (mile). Verify that the speedometer is accurately reporting the vehicle speed.STOP