SCREW 2839121 - Caterpillar

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(1) Laser Beam (2) Laser Receivers
Verify that the laser beam is striking the laser receivers.Expected Result:The laser beam is striking the laser receivers.Results:
YES - The laser beam is striking the laser receivers. Proceed to Test Step 6.
NO - The laser beam is not striking the laser receivers.Repair: Adjust the transmitter in order to ensure that the laser beam is striking the laser receivers. Perform the valve calibration again.STOPTest Step 5. CHECK THE MACHINE VOLTAGE
Disconnect the wire harness from the laser receiver.
Measure the voltage between pin "A" and pin "F".Expected Result:The voltage is machine voltage.Results:
YES - The voltage is machine voltage.Repair: Repair the laser receiver or replace the laser receiver. Repeat the calibration procedure.STOP
NO - The voltage is not machine voltage. Proceed to Test Step 8.Test Step 6. CHECK THE RESISTANCE OF THE CAN CIRCUIT
Illustration 2 g01379685
Place the key start switch and the disconnect switch in the OFF position.
Take the following measurement at the connector for the right or the left sensor harness. Measure the resistance between contact C (wire L854-YL) and contact D (wire L855-GN).Expected Result:The resistance measurement is 60 6 ohms.Results:
YES - The resistance measurement is 60 6 ohms. Proceed to Test Step 8.
NO - The resistance measurement is NOT 60 6 ohms. Proceed to Test Step 8.Test Step 7. CHECK THE CAN TERMINATION RESISTORS.
Place the key start switch and the disconnect switch in the OFF position.
Disconnect the 3-pin connector for all four of the termination resistors.
Measure the resistance between contact A (wire L854-YL) and contact B (wire L855-GN) for all four resistors. Note the resistance.Expected Result:The resistance measurements are 120 12 ohms.Results:
YES - The resistance measurements are 120 12 ohms. Reconnect the resistors. Proceed to Test Step 8.
NO - One or all resistance measurements is NOT 120 12 ohms. Repair: Replace the termination resistor(s) that did not measure 120 12 ohms.STOPTest Step 8. CHECK THE WIRING HARNESS OF THE LASER RECEIVER
Disconnect the wiring harness from the laser receiver.
Use the multimeter probes in order to measure the resistance from each contact in one end of the harness to the same contact in the opposite end of the harness.
Check for shorts between the contacts for the CAN data link. Check for shorts to power and ground.Expected Result:The resistance is less than 5 ohms.Results:
NOT OK - The resistance is greater than 5 ohms. There is an open in the machine harness.Repair: Repair the harness or replace the harness.STOP
OK - The resistance is less than 5 ohms. The harness circuit is correct. Repair: Reconnect the wire harnesses and repeat the calibration procedure. If the diagnostic code is not active at this time, the initial diagnostic code may have been caused by a poor electrical connection or a short at one of the harness connectors that was disconnected and reconnected. If the diagnostic code continues to occur, contact your technical communicator for a possible consultation with Caterpillar.STOP