Kohler Command PRO ECV630 Service Manual page 62

EFI SYSTEM-BOSCH
TROUBLESHOOTING
Troubleshooting Guide
Condition
Faulty/malfunctioning ignition system.
Dirty air filter.
Insufficient fuel delivery.
Improper governor adjustment.
Low Power Plugged/restricted exhaust.
One injector not working.
Basic engine problem exists.
TPS faulty or mounting exist.s
Throttle plates in throttle body/intake manifold not fully opening to WOT stop (if so equipped).
Electrical System
NOTE: When performing voltage or continuity tests, avoid putting excessive pressure on or against connector pins.
Flat pin probes are recommended for testing to avoid spreading or bending terminals.
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, operation of voltage sensitive components such as 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 wiring harness or connections than by EFI
components. Even small amounts of corrosion or oxidation on terminals can interfere with milliamp currents used in
system operation. Cleaning connectors and grounds will solve problems in many cases. In an emergency situation,
simply disconnecting and reconnecting connectors may clean up contacts enough to restore operation, at least
temporarily.
If a fault code indicates a problem with an electrical component, disconnect ECU connector and test for continuity
between component connector terminals and corresponding terminals in ECU connector using an ohmmeter. Little
or no resistance should be measured, indicating that wiring of that particular circuit is OK. An illustrated listing of
numerical terminal locations, for each style of ECU/connector is provided on pages 63 and 65.
62
Possible Cause
KohlerEngines.com 24 690 02 Rev. D