Caterpillar — Watchdog Alarm - Troubleshoot

Testing & diagnosis · Digital Voltage Regulator

From a Caterpillar service manual — check it applies to your exact model before use.

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Procedure

1. A 602 alarm is a watchdog alarm; a watchdog alarm can be generated during engine cranking.
2. In order to prevent this alarm, provide a separate constant 24 VDC supply to the regulator.
3. If a constant 24 VDC supply is not available, remove all battery power to the regulator during engine cranking.

Source: Caterpillar service manual. Steps and values are as documented; always cross-check against the official manual and any later revisions for your exact serial number before servicing.

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