MPI <4G6> -
Troubleshooting
13A-11
NG
Replace the engine-ECU <M/T> or
engine-A/T-ECU <A/T>.
OK
Check the trouble symptoms.
Check the harnesses between the
air flow sensor and the engine-ECU
<M/T> or engine-A/T-ECU <A/T> and
between the air flow sensor and the
engine control relay, and repair if
necessary.
OK
NG
Check the following connectors:
C-40 <M/T>, C-176 <A/T>, C-31
NG
Repair
Check the trouble symptoms.
NG
Replace the air flow sensor.
OK
Measure the output waveform at air
flow sensor connector B-12 (by
using an analyzer).
D
Use test harness (MB991709) to
connect the connector, and
measure at the pick-up harness.
D
Engine: Idling
D
Voltage between terminal 3 and
earth
OK:
Waveforms should be dis-
played on P.13A-88 (In-
spection Procedure Using
an Analyzer) and noise
should not be displayed in
the waveform.
NG
Replace the engine-ECU <M/T> or
engine-A/T-ECU <A/T>.
OK
Check the trouble symptoms.
OK
Check the harness between the air
flow sensor and the engine-ECU
<M/T> or engine-A/T-ECU <A/T>.
NG
Repair
NG
Check the following connector:
C-34 <M/T>, C-177 <A/T>
NG
Repair
OK
Measure at air flow sensor connector
B-12.
D
Use test harness (MB991709) to
connect the connector, and
measure at the pick-up harness.
D
Voltage between terminal 7 and
earth
OK:
Engine: Idling
0-1V
Engine speed: 3,000 r/min
6-9V
OK
Replace the air flow sensor.
OK
Check the harness between the air
flow sensor and the engine-ECU
<M/T> or engine-A/T-ECU <A/T>.
NG
Repair
NG
Check the following connector:
C-34 <M/T>, C-177 <A/T>
NG
Repair
OK
Measure at air flow sensor connector
B-12.
D
Use test harness (MB991709) to
connect the connector, and
measure at the pick-up harness.
D
Ignition switch: ON
D
Voltage between terminal 7 and
earth
OK:
7-8V
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