Usage:
Powering the electronic control system on a dedicated fused circuit will reduce the possibility of degraded electronic control system performance due to voltage transients. Additional loads should not be connected between the ECM and ECM circuit protection. Refer to Schematic and Installation Section (in this manual) for information regarding required connections.
The ECM switched battery connection is made to Customer Connector P3 pin-26. To prevent engine shutdown in the event of a short circuit in the vessel harness, the control system must be powered on a dedicated protected circuit. The wire size should be #14 AWG. This connection should be made through switched battery so it will be powered when the keyswitch (or engine control switch) is in the OFF position.
Circuit protection for this circuit must be 15 Amps (for 12V or 24V system) and rated for a continuous duty load of 8.0 Amperes at 12 VDC (5.0 Amperes at 24 VDC).
NOTE: DO NOT use in-line fuses for circuit protection. Caterpillar prefers using circuit breakers for circuit protection. Circuit breakers should be located with other vessel circuit protection in a centrally located, dedicated panel.
If automatically resetting circuit breakers are used, consideration of the breaker location environment and its effect on the trip point is critical. The trip point of some circuit breakers can be significantly reduced below the rated trip point if exposed to high temperatures. This can cause intermittent shutdowns resulting in incorrectly replaced engine electronic components.
An ECM diagnostic strategy monitors ECM battery voltage, and is triggered if the voltage to the ECM drops below 83% of the system voltage.
The Marine Engine can operate in 24 VDC electrical systems with circuit protection. The specification is the same as for 12 VDC systems and continuous duty load is 5.0 Amperes at 24 VDC.