Electrical System - Kohler LH630-775 Service Manual

Electrical System

The EFI system is a 12 VDC negative ground system,
designed to operate down to a minimum of 7.0 volts.
If system voltage drops below this level, the operation
of voltage sensitive components such as the ECU, fuel
pump, and injectors will be intermittent or disrupted,
causing erratic operation or hard starting. A fully
charged, 12 volt battery with a minimum of 350 cold
cranking amps is important in maintaining steady
and reliable system operation. Battery condition and
state of charge should always be checked first when
troubleshooting an operational problem.
Keep in mind that EFI-related problems are more
often caused by the wiring harness or connections
than by the EFI components. Even small amounts of
corrosion or oxidation on the terminals can interfere
with the milliamp currents used in system operation.
Cleaning the connectors and grounds will solve
problems in many cases. In an emergency situation,
simply disconnecting and reconnecting the
connectors may clean up the contacts enough to
restore operation, at least temporarily.
If a fault code indicates a problem with an electrical
component, disconnect the ECU connector and test for
continuity between the component connector
terminals and the corresponding terminals in the
ECU connector using an ohmmeter. Little or no
resistance should be measured, indicating that the
wiring of that particular circuit is OK. An illustrated
listing of numerical terminal locations is provided
below.
NOTE: When performing voltage or continuity tests,
avoid putting excessive pressure on or
against the connector pins. Flat pin probes
are recommended for testing to avoid
spreading or bending the terminals.
Section 5B
EFI Fuel System
5B.23
5B