C4.4 and C6.6 Industrial Engines and Engines for Caterpillar Built Machines Caterpillar

This condition indicates that the battery circuit to the Electronic Control Module (ECM) has excessive voltage while the engine is running.

The ECM detects the following conditions:

• For 24 Volt DC systems, the battery voltage to the ECM exceeds 32 Volts for more than 0.5 seconds.

• For 12 Volt DC systems, the battery voltage to the ECM exceeds 16 Volts for more than 0.5 seconds.

• The keyswitch is in the ON mode.

• The engine is not cranking.

• The engine is running for more than 30 seconds.

System Response:

The ECM will log the diagnostic code. If equipped, the warning lamp may come on.

None

This diagnostic code will detect excessively high voltage in the battery circuit to the Electronic Control Module (ECM) while the engine is running.

Test Step 1. Perform the following diagnostic procedure: Ignition Keyswitch Circuit and Battery Supply Circuit - Test

Results:

• OK - STOP