Troubleshooting; General Troubleshooting Information; Wiring Diagrams - Northern Lights OM-C3 Operator's Manual

Marine engines

Table of Contents

General Troubleshooting Information

Troubleshooting engine problems can be difficult. Engine

wiring diagrams are provided in this section to help isolate

electrical problems on engines using John Deere wiring

harness and instrument (gauge) panel.

Later in this section is a list of possible engine problems

that may be encountered, accompanied by possible

causes and corrections. The illustrated diagrams and

troubleshooting information are of a general nature; final

design of the overall system for your engine application

may be different. See your engine distributor or servicing

dealer if you are in doubt.

For Electronically Controlled Engines: The Engine

Control Unit (ECU) has the ability to detect problems

internally and in the electronic control system. This

includes determining if any of the sensor input voltages

are too high or too low, if the camshaft and crankshaft

position sensor inputs are valid, and if the unit injector

solenoids are responding properly.

If the ECU detects a problem with the electronic control

system a Diagnostic Trouble Code (DTC) specific to the

failed system will be stored in the ECU's memory.

There are two types of DTCs:

•

Active

•

Inactive (Stored)

Active DTCs indicate that the failure is occurring. These

type of failures are sometimes called "hard" failures. They

can be accessed on the diagnostic gauge (A) on the

instrument panel.

Inactive or stored DTCs indicate that a failure has occurred

in the past, but is not currently occurring. This type of

"stored" DTC can be caused by an "intermittent" failure.