324E and 329E Excavators and 329E MHPU Mobile Hydraulic Power Unit Machine Electronic Control System Caterpillar

Illustration 1	g02888579
Schematic of the Laser Catcher circuit

This diagnostic code is associated with the laser receiver. This diagnostic code is active if the laser receiver is not detected on the data link.

Test Step 1. CHECK THE MACHINE HARNESS

1. Verify that the contacts of the two connectors on the machine harness are properly wired. Refer to electrical schematic UENR1517.

Expected Result:

The harness is wired correctly.

Results:

• YES - The machine harness is wired correctly. Proceed to Test Step 2.

• NO - The machine harness is NOT wired correctly.

  Repair: Repair the harness or replace the harness.

  STOP

Test Step 2. CHECK THE RESISTANCE OF THE CAN DATA LINK

1. Place the key start switch and the disconnect switch in the OFF position.

2. Take the following measurement at the harness connector for the laser receiver. Measure the resistance across contact "3" and contact "4". Note the resistance.

Expected Result:

The resistance measurement is 60 (±5) ohms.

Results:

• YES - The resistance measurement is 60 (±5) ohms. Proceed to Test Step 4.

• NO - The resistance measurement is NOT 60 (±5) ohms. Proceed to Test Step 3.

Test Step 3. CHECK THE TERMINATION RESISTOR

1. Disconnect the connector for the termination resistor.

2. Measure the resistance across contact "A" and contact "B" of the termination resistor. Note the resistance.

3. Measure the resistance across contact "C" and contact "D" of the quick disconnect at the laser receiver. Note the resistance.

Expected Result:

The resistance measurement is 60 (±5) ohms.

Results:

• YES - The resistance measurement is 60 (±5) ohms. Proceed to Test Step 4.

• NO - The resistance measurement is NOT 60 (±5) ohms.

  Repair: If the termination resistor did not measure 60 (±5) ohms, then replace the termination resistor.If the measurement at the connector for the termination resistor was not 60 (±5) ohms, replace the harness or repair the harness.

  STOP

Test Step 4. CHECK THE MACHINE HARNESS

1. Disconnect the harness connectors from the ECM.

2. Measure the resistance from contact "J2-45" on the ECM connector to contact "C" on the connector. Note the resistance.

3. Measure the resistance from contact "J2-46" on the ECM connector to contact "D" on the connector. Note the resistance.

Expected Result:

The resistance measurements are 60 (±5) ohms.

Results:

• YES - All of the resistance measurements are 60 (±5) ohms.

  Repair: Contact your technical communicator for a possible consultation with Caterpillar.

  STOP

• NO - One of the resistance measurements are greater than 70 ohms.

  Repair: Repair the harness or replace the harness.

  STOP