AccuGrade® Laser (CB420) Caterpillar

Illustration 1	g01548493

This diagnostic code is associated with an internal problem with one of the AccuGrade - Grade Control System devices. An unknown device is detected.

Test Step 1. CYCLE POWER TO THE SYSTEM

1. Move the "Power/Setup" Switch for the AccuGrade - Grade Control System to the "OFF" position.

2. Turn the keyswitch for the machine to the "OFF" position.

3. Turn the keyswitch for the machine to the "ON" position.

4. Move the "Power/Setup" Switch for the AccuGrade - Grade Control System to the "ON" position.

Expected Result:

The diagnostic code becomes inactive.

Results:

• YES - The diagnostic code becomes inactive. Return the machine to normal operation.STOP

• NO - The diagnostic code is still active. Proceed to Test Step 2.

Test Step 2. CHECK THE HARNESS FOR AN OPEN.

1. Move the "Power/Setup" Switch on the Display for the AccuGrade - Grade Control System to the OFF position.

2. Turn the key start switch and the disconnect switch for the machine to the OFF position.

3. Disconnect the harness from the right knuckle connector.

4. Measure the resistance between pin "B" and pin "F".

Expected Result:

The resistance is less than 5.0 ohms.

Results:

• OK - The resistance is less than 5.0 ohms. The machine harness is correct. Proceed to Test Step 3.

• NOT OK - The resistance is greater than 5000 ohms. The resistance measurement is not correct. There is an open circuit in the machine harness.

  Repair: The open is in wire T745-YL of the machine harness. Repair the machine harness or replace the machine harness.

  STOP

Test Step 3. CHECK THE HARNESS FOR A SHORT.

1. Move the "Power/Setup" Switch on the Display for the AccuGrade - Grade Control System to the OFF position.

2. Turn the key start switch and the disconnect switch for the machine to the OFF position.

3. Disconnect the harness from the left knuckle connector.

4. Measure the resistance between pin "B" and pin "F".

Expected Result:

The resistance is greater than 5000 ohms.

Results:

• OK - The resistance is greater than 5000 ohms. The machine harness is correct. Proceed to Test Step 4.

• NOT OK - The resistance is less than 5000 ohms. The resistance measurement is not correct. There is an short circuit in the machine harness.

  Repair: The short is in wire T748-PK of the machine harness. Repair the machine harness or replace the machine harness.

  STOP

Test Step 4. CHECK IF THE DIAGNOSTIC CODE REMAINS.

1. Inspect the contacts of the harness connectors and clean the harness connectors.

2. Reconnect all harness connectors.

3. Turn the disconnect switch and the key start switch to the ON position.

4. Move the "Power/Setup" Switch on the Display for the AccuGrade - Grade Control System to the ON position.

5. Operate the machine.

6. Check the status of the "CB 23".

Expected Result:

The "CB 23" diagnostic code is active.

Results:

• YES - The "CB 23" diagnostic code is active. The diagnostic code has not been corrected.

  Repair: Exit this procedure and perform this procedure again. If the cause of the diagnostic code is not found, contact the Technical Communicator at your dealership for a possible consultation with Caterpillar.

  STOP

• NO - The "CB 23" diagnostic code is not active. The diagnostic code does not exist at this time.

  Repair: The initial diagnostic code was probably caused by a poor electrical connection at one of the harness connectors that was disconnected and reconnected. Resume normal machine operation.

  STOP