PleasureCraft Engine Group 5.0L, Diagnostic Manual, Page: 10 / 337

1 - 6 General Information 5.0/5.7/6.0/8.1L
MEFI 4 - PCM
Figure 1-4 - Test Light Amperage Draw Test
DC Amps
testlight
*
BATTERY
+
-
If the ammeter indicates
less
than 3/10 amp(.3A) current flow,
the testlight is
safe
to use.
If the ammeter indicates
more
than 3/10 amp(.3A) current flow,
the testlight is
not safe
to use.
I 22307
Service Precautions
The following requirements must be observed when
working on MEFI equipped engines.
1. Before removing any ECM system component,
disconnect the negative battery cable.
2. Never start the engine without the battery being solidly
connected.
3. Never separate the battery from the on-board electrical
system while the engine is running.
4. Never separate the battery feed wire from the charging
system while the engine is running.
5. When charging the battery, disconnect it from the
vehicle’s electrical system.
6. Ensure that all cable harnesses are connected solidly
and the battery connections are thoroughly clean.
7. Never connect or disconnect the wiring harness at the
ECM when the ignition is switched “ON.”
8. Before attempting any electric arc welding on the
vehicle, disconnect the battery leads and the ECM
connector(s).
9. When steam cleaning engines, do not direct the nozzle
at any ECM system components. If this happens,
corrosion of the terminals or damage of components
can take place.
10. Use only the test equipment specifi ed in the diagnostic
procedures, since other test equipment may either give
incorrect test results or damage good components.
11. All measurements using a multimeter must use a digital
meter with a rating of 10 megaohm input impedance.
12. When a test light is specifi ed, a “low-power” test light
must be used. Do not use a high-wattage test light.
While a particular brand of test light is not suggested,
a simple test on any test light will ensure it to be safe
for system circuit testing (Figure 1-4). Connect an
accurate ammeter (such as the high-impedance digital
multimeter) in series with the test light being tested,
and power the test light ammeter circuit with the
vehicle battery.