คำตอบที่ 15
FAILURE TO START TEST
To prevent unnecessary diagnostic time and wrong
test results, the Testing For Spark At Coil test
should be performed prior to this test.
WARNING: SET PARKING BRAKE OR BLOCK THE
DRIVE WHEELS BEFORE PROCEEDING WITH THIS
TEST.
(1) Unplug the ignition coil harness connector at
the coil (Fig. 9).
(2) Connect a set of small jumper wires (18 gauge
or smaller) between the disconnected harness terminals
and the ignition coil terminals. To determine
polarity at connector and coil, refer to the Wiring
Diagrams section.
(3) Attach one lead of a voltmeter to the positive
(12 volt) jumper wire. Attach the negative side of
voltmeter to a good ground.
(4) Determine that sufficient battery voltage (12.4
volts) is present for the starting and ignition systems.
(5) Crank the engine for 5 seconds while monitoring
the voltage at the coil positive terminal:
† If the voltage remains near zero during the
entire period of cranking, refer to On-Board Diagnostics
in Group 14, Fuel Systems. Check the Powertrain
Control Module (PCM) and auto shutdown
relay.
† If voltage is at or near battery voltage and drops
to zero after 1-2 seconds of cranking, check the powertrain
control module circuit. Refer to On-Board
Diagnostics in Group 14, Fuel Systems.
† If voltage remains at or near battery voltage
during the entire 5 seconds, turn the key off. Remove
the three 32-way connectors (Fig. 10) from the PCM.
Check 32-way connectors for any spread terminals or
corrosion.
(6) Remove test lead from the coil positive terminal.
Connect an 18 gauge jumper wire between the
battery positive terminal and the coil positive terminal.
(7) Make the special jumper shown in (Fig. 11).
Using the jumper, momentarily ground the ignition
coil driver circuit at the PCM connector (cavity A-7).
For cavity/terminal location of this circuit, refer to
Group 8W, Wiring. A spark should be generated at
the coil cable when the ground is removed.
(8) If spark is generated, replace the PCM.
(9) If spark is not seen, use the special jumper to
ground the coil negative terminal directly.
(10) If spark is produced, repair wiring harness for
an open condition.
