AP355F Asphalt Paver Propel Systems Caterpillar

Troubleshooting Problem List

Problem: The machine does not move in either direction.

Probable Cause:

1. The hydraulic oil level is low.

2. The propel control is faulty.

3. The charge pressure for the propel pump is low.

4. The system pressure is low.

5. The combination valve is faulty.

6. The electronic displacement control (EDC) is faulty.

7. The parking brake is not disengaging.

Problem: The machine will move in one direction only.

Probable Cause:

1. The propel control is faulty.

2. The combination valve is faulty.

3. The charge check valves are faulty.

4. The control valve is faulty.

5. The shuttle valve is faulty.

6. The oil in the servo system of the propel pump is contaminated.

Problem: The machine cannot be placed in NEUTRAL.

Probable Cause:

1. The propel control is faulty.

2. The control valve is faulty.

3. The propel pump is faulty.

4. The electrical displacement control (EDC) is not adjusted correctly.

Problem: The system is overheating.

Probable Cause:

1. The hydraulic oil level is low.

2. The hydraulic oil cooler is plugged or dirty.

3. The suction filter is clogged.

4. The combination valve is faulty.

5. The system pressure is high.

6. There is excessive load on one or more systems.

7. There is a restriction in a line.

8. The oil cooler bypass valve is faulty.

9. The charge pressure is low.

Problem: Response of the propel system is sluggish.

Probable Cause:

1. The charge pressure is low.

2. The control valve is faulty.

3. The oil is not at operating temperature.

4. The setting for the relief valve is incorrect.

Problem: Charge pressure is low in NEUTRAL and during FORWARD and REVERSE operation.

Probable Cause:

1. The charge relief valve for the propel system is faulty.

Problem: Charge pressure is low during FORWARD and REVERSE operation.

Probable Cause:

1. The flushing relief valve for the propel motor is faulty.

Problem: The machine creeps in either direction when the speed control is set at zero.

Probable Cause:

1. The pump neutral position is not properly adjusted.

2. The electrical circuit contains a fault.

3. The slope is too steep for the chosen speed range of the machine.