D3G, D4G and D5G Track-Type Tractors AccuGrade Laser Caterpillar

Illustration 1	g01067613

This diagnostic code is shown when the AccuGrade Laser system display reads the voltage of the circuit as being below normal. This condition may occur on machine start-up.

System Response:

When this diagnostic code occurs, low voltage is observed at the "display".

Test Step 1. CHECK THE ACCUGRADE LASER SYSTEM FUSES

1. Check the AccuGrade Laser fuses, "Fuse 1 (A3 - A2)", "Fuse 2 (C3 - C2)", and "Fuse 3 (D3 - D2)".

Expected Result:

One or more of the fuses are blown.

Results:

• YES - One or more of the fuses are blown.

  Repair: Replace the blown fuses.

  Stop.

• NO - The fuses are not blown. Proceed to Test Step 2

Test Step 2. CHECK THE WIRE HARNESS

Refer to Schematic, RENR7853.

1. Turn the power/setup switch on the display to the OFF position.

2. Disconnect the wire harness from the display at connector "CB - C2".

3. Install a jumper wire between pin "E" and pin "F" on the harness connector.

4. Turn the power/setup switch on the display to the ON position.

5. Measure the voltage between pin "A" and pin "F" on the wire harness.

Expected Result:

Voltage measured between pin "A" and pin "F" is machine voltage.

Results:

• YES - Voltage measured between pin "A" and pin "F" is machine voltage. Proceed to Test Step 3.

• NO - Voltage measured between pin "A" and pin "F" is not machine voltage. Proceed to Test Step 4.

Test Step 3. CHECK THE DISPLAY

Refer to Schematic, RENR7853.

1. Move the power/setup switch on the display to the ON position.

2. Measure the resistance between pin "A" and pin "E" on the connector that is located on the display

Expected Result:

The measured resistance is less than 5 Ohms.

Results:

• YES - The measured resistance is less than 5 Ohms.. Proceed to Test Step 4.

• NO - The measured resistance is greatr than 5000 Ohms.

  Repair: The display is faulty. Replace the display.

  Stop.

Test Step 4. CHECK THE POWER SUPPLY MODULE

Refer to Schematic, RENR7853.

1. Access the power module in order to remove the 8 pin main harness connector.

2. Measure the voltage between pin "A" and pin "GND" on the power module connector .

Expected Result:

Voltage measured between pin "A" and pin "GND" on the power module connector is machine voltage.

Results:

• YES - Voltage measured between pin "A" and pin "GND" on the power module connector is machine voltage.

  Repair: Repair or replace the wire harness from the display to the power supply module.

  Stop.

• NO - Voltage measured between pin "A" and "GND" on the power module connector is not machine voltage.

  Repair: Replace the power supply.

  Stop.