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Mitsubishi Galant (2004+). Manual - part 1081
MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS
TSB Revision
MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>
13B-17
ON-BOARD DIAGNOSTICS
The powertrain control module (PCM) monitors the input/output signals (some signals all the time and others
under specified conditions) of the PCM. When a malfunction continues for a specified time or longer after the
irregular signal is initially monitored, the PCM judges that a malfunction has occurred. After the PCM first
detects a malfunction, a diagnostic trouble code is recorded when the engine is restarted and the same mal-
function is re-detected. However, for items marked with a "*", a diagnostic trouble code is recorded on the first
detection of the malfunction. There are 126 diagnostic items. The diagnostic results can be read out with a
scan tool. Since memorization of the diagnostic trouble codes is backed up directly by the battery, the diag-
nostic 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 PCM connector is disconnected. In addition, the diagnostic trouble
code can also be erased by turning the ignition switch to ON and sending the diagnostic trouble code erase
signal from scan tool MB991958 to the PCM.
NOTE: If the sensor connector is disconnected with the ignition switch turned on, the diagnostic trouble code
is memorized. In this case, send the diagnostic trouble code erase signal to the PCM in order to erase the
diagnostic memory. The 126 diagnostic items are all indicated sequentially from the smallest code number.
The PCM records the engine operating condition when the diagnostic trouble code is set. This data is called
"Freeze-frame" data. This data can be read by using the scan tool, and can then be used in simulation tests
for troubleshooting. Data items are as follows:
NOTE: If the PCM detects multiple malfunctions, the PCM stores the "Freeze - frame" data for only the first
item that was detected, However if the PCM detects a misfire or a fuel system malfunction, regardless of the
order in which the malfunction was detects
NOTE: As for Diagnostic trouble code P1603, "freeze frame" data is not memorized.
MUT-III SCAN TOOL
DISPLAY
ITEM
No.
DATA
UNIT
ECT SENSOR
21
Engine coolant temperature sensor
°C or °F
ENGINE LOAD
87
Calculated load value
%
ENGINE SPEED.
22
Crankshaft position sensor
r/min
IAT SENSOR
13
Intake air temperature sensor
°C or °F
IG. TIMING ADV
44
Ignition coils and ignition power
deg
LONG TRIM B1
81
Long-term fuel trim bank 1
%
LONG TRIM B2
83
Long-term fuel trim bank 2
%
MAP/MDP SNSR
32
Manifold absolute pressure sensor
kPa or in.Hg
SHORT TRIM B1
82
Short-term fuel trim bank 1
%
SHORT TRIM B2
84
Short-term fuel trim bank 2
%
SYS. STATUS B1
88
Fuel control system status bank1 (right)
• Open loop
• Closed loop
• Open loop-drive
condition
• Open loop-DTC set
• Closed loop-O
2
(rear)
failed
SYS. STATUS B2
89
Fuel control system status bank1 (left)
• Open loop
• Closed loop
• Open loop-drive
condition
• Open loop-DTC set
• Closed loop-O
2
(rear)
failed