Mercury MerCruiser D2.8L D-Tronic Service Manual page 643

SERVICE MANUAL NUMBER 22
Troubleshooting Charts (Continued)
90-860074--1 FEBRUARY 2002
Definition: Problem occurs randomly. May or may not store a Diagnostic
Trouble Code (DTC).
Do NOT use the diagnostic trouble code charts for intermittent problems, unless
instructed to do so. If a fault is intermittent, incorrect use of diagnostic trouble code
charts may result in replacement of good parts.
Most intermittent problems are caused by faulty electrical connections or wir-
ing. Perform careful check of suspected circuits for:
1. Poor mating of the connector halves or terminals not fully seated in the con-
nector body (loose).
2. Improperly formed or damaged terminals and or connectors. All connector
terminals and connectors in problem circuit should be carefully reformed or
replaced to insure proper contact tension.
3. Poor terminal to wire connection (crimping).
An intermittent may be caused by:
1. Electrical system interference caused by a sharp electrical surge. Normally,
the problem will occur when the faulty component is operated.
2. Improper installation of electrical options, such as lights, ship to shore radios,
sonar, etc.
3. Improperly routed wires. Wires should be routed AWAY from charging system
components.
4. Arching at part of internal circuitry shorted to ground such as in starters, relays
and alternators.
If a visual/physical check does not find the cause of the problem, the EDI system
can be tested with a voltmeter or a scan tool connected while observing the
suspected circuit. An abnormal reading, when the problem occurs, indicates the
problem may be in that circuit.
INTERMITTENTS
EDI DIAGNOSIS
Page 5E-75