MULTIPORT FUEL INJECTION(MFI) DIAGNOSIS
TSB Revision
MULTIPORT FUEL INJECTION (MFI) <3.0L>
13B-9
INSPECTION USING SCAN TOOL MB991502,
DATA LIST AND ACTUATOR TESTING
Required Special Tool:
MB991502: Scan Tool (MUT-II)
CAUTION
To prevent damage to scan tool MB991502, always turn the
ignition switch to the "LOCK" (OFF) position before
connecting or disconnecting scan tool MB991502.
1. Connect scan tool MB991502 to the data link connector.
2. Turn the ignition switch to the "ON" position.
3. Carry out inspection by means of the data list and the
actuator test function. If there is an abnormality, check and
repair the chassis harnesses and components. Refer to
Data List Reference Table (
P.13B-487
). Refer to Actuator
Test Reference Table (
P.13B-499
) .
4. Re-check using scan tool MB991502 and check to be sure
that the abnormal input and output have returned to normal
because of the repairs.
5. Erase the diagnostic trouble code(s).
6. Turn the ignition switch to the "LOCK" (OFF) position.
7. Disconnect scan tool MB991502 from the data link
connector.
8. Start the engine again and do a test drive to confirm that the
problem is eliminated.
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
malfunction is re-detected. However, for items marked with a "*," a diagnostic trouble code is recorded on the
first detection of the malfunction. There are 68 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
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 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 MUT-II (MB991502) 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 61 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: As for Diagnostic trouble code P1603, "freeze frame" data is not memorized.
AC003081 AB
16 PIN
MB991502
DATA
UNIT
Engine coolant temperature
°
C or
°
F
Engine speed
r/min
Vehicle speed
km/h or mph