Mitsubishi 3000GT Service Manual page 123

MULTIPORT FUEL INJECTION - Troubleshooting
NOTE
1. After the Engine Control Module (ECM) detects
a malfunction, the check engine/malfunction
indicator lamp illuminates when the engine is
next turned on and the same malfunction is
re-detected.
However, for items marked with a 'I*", the check
engine/malfunction indicator lamp illuminates
on the first detection of the malfunction.
2. After the check engine/malfunction indicator
lamp illuminates, it will be switched off under
the following conditions.
Caution
If the check engine/malfunction indicator lamp illuminates because of a malfunction of the ECM,
transmission between the scan tool and the ECM cannot occur. In this case, the diagnostic trouble
code cannot be read.
When the ECM
l
l
CHECK ENGINE MALFUNCTION INDICATOR LAMP
INSPECTION
(1) Check that when the ignition switch is turned on, the
lamp illuminates for about 5 seconds and then goes out.
(2) If the lamp does not illuminate, check for open circuit
in harness, blown fuse and blown bulb.
ON-BOARD DIAGNOSTIC <Up to 1995
models>
The engine control module monitors the input/output signals
(some signals at all times and the others under specified
conditions) of the engine control module.
When it is noticed that an irregularity has continued for a
specified time or longer from when the irregular signal is
initially monitored, passing a certain number, the engine con-
trol module judges that an irregularity has occurred, memorizes
the diagnostic trouble code, and outputs the signal to the
diagnostic output terminal.
There are 23 diagnostic items, including the normal state,
and the diagnostic results can be read out with a voltmeter
or scan tool.
Moreover, since memorization of the diagnostic trouble codes
is backed up directly by the battery, the diagnostic results
are memorized even if the ignition key is turned off. The
diagnostic trouble codes will, however, be erased when the
battery terminal or the engine control module connector is
disconnected.
The diagnostic trouble code can also be erased by turning
on the ignition switch and sending the diagnostic trouble code
erase signal from the scan tool to the engine control module.
TSB Revision
monitored the powertrain
malfunction three times* and detected no
malfunction.
In this case, one time indicates from engine
start to stop.
For misfiring or a fuel trim malfunction, when
driving conditions (engine speed, engine
coolant temperature, etc.) are similar to those
when the malfunction was first recorded.