P0102,P0103
Symptom: CHECK ENGINE lamp (MIL) on. Engine reluctant to start and poor
driveability. High fuel consumption. Lumpy idle.
Mass air flow sensor
Fault symptoms
CHECK ENGINE lamp (MIL) on. Engine reluctant to start and poor
driveability. High fuel consumption. Lumpy idle.
Conditions
P0102 Engine rpm <1400 rpm and intake air mass< 0.45 g/s (open circuit/shorting
to ground).
P0103 Engine rpm < 3600 rpm and intake air mass>111 g/s.
Diagnostic help
The performance of the mass air flow sensor can be ascertained with an ISAT scan
tool.
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Connect the ISAT Scan
Tool.
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Select "READ FUNCTIONS".
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Select "MASS AIR FLOW SENSOR".
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Check that the ISAT scan tool shows the following air mass as a function of
engine rpm:
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idling speed . . . . . . . . . . . . . . . . . .
. . . . . . about 1.0 V
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at 2500 rpm . . . . . . . . . . . . . . . . . . . . about 1.5 V
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All electrical equipment disconnected and selector lever in position N.
Slightly higher values will be obtained with a cold engine.
Check the wiring
Intermittent faults may occur as a result of temporary short circuits and breaks in the
wiring. Jiggle the wiring at several points and in different directions to ascertain whether the
wiring harness, including any connectors, is causing the trouble. Observe the multimeter,
ISAT scan tool or test lamp while doing this.
Diagnostic procedure
1. Check the control module's mass air flow sensor input
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Unplug the mass air flow
sensor's 4-pin connector.
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Connect the ISAT Scan
Tool.
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Turn the ignition switch to the ON position.
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Select "READ FUNCTIONS".
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Select "MASS AIR FLOW SENSOR".
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The ISAT scan tool should show a reading of about 0.0 V (about 0.0
g/s).
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Connect a 1.5 V battery in good
condition to pins 4 and 2 of the connector.
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The ISAT scan tool should show a reading of about 1.5 V (about 10
g/s).
Are both readings OK?
Continue with point 3.
Continue with point 2.
2. Check the wiring between the control module and mass
air flow sensor
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Check for continuity
between:
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The resistance reading obtained should be less than 1
ohm.
Is the wiring OK?
Continue with point 4.
Rectify the fault. Continue with point 4.
3. Check the mass air flow sensor's power supply and ground
connections
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Check for continuity
between:
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The resistance reading obtained should be less than 1 ohm.
Is the wiring OK?
Change the mass air flow sensor. Continue with point 4.
Rectify the fault. Continue with point 4.
4. Final check
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Clear the diagnostic trouble
code.
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Implementation of driving cycle:
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Evaluation of driving cycle:
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Has the diagnostic trouble code recurred?
Continue as described in
.
The steps taken to rectify the fault were
correct.
