2007/02/05 Caterpillar

Engine:

C6.6 (S/N: 666211-UP)

C3.3 (S/N: E3J201-UP)

C4.4 (S/N: 4442-UP)

Industrial Engine:

3054C (S/N: 3347-UP)

3056E (S/N: 356125-UP)

3054E (S/N: 304336-UP)

A potential issue with the diode may occur when the alternator has an excessive reverse voltage or a voltage that is too high. The affected alternators are listed in table 1.

Reverse voltage and a voltage that is too high in the application may be due to the following reasons.

• Incorrect jump starting of the machine

• The battery is incorrectly isolated when the machine is being welded.

• Disconnect the charging circuit when the machine is operating.

• Incorrect isolation of the battery

• Loose connections in the charging system

• Inadequate ground path from the alternator to the battery

Jump Starting

For jump starting, refer to Operation and Maintenance Manual, "Starting with Jump Start Cables" for the correct procedure.

Welding

For welding, refer to Operation and Maintenance Manual, "Welding on Engines with Electronic Controls" for the correct procedure.

Disconnection of the Charging Circuit for a Machine that is Operating

• Do not stop the machine with the isolation switch for the battery.

• Ensure that the machine is stopped before disconnecting the battery.

• Before the electrical connections are inspected ensure that the battery is isolated from the circuit. Use the isolation switch for the battery or the disconnection of the battery terminal.

The ground path from the alternator to the battery

Ensure that the connections in the charging circuit are maintained. The alternator requires a good earth from the case of the alternator back to the earth of the battery. If the alternator is grounded by using the cylinder block, check that a good connection exists between the alternator and the cylinder block. If the alternator bracket is painted, then the bracket should be removed. Any paint on the mounting surfaces of the alternator bracket should be removed.