Ford Corsar Repair Manual page 227

TROUBLE DIAGNOSES
DIAGNOSTIC PROCEDURE 20 (Cont'd)
CODE 34
-
AIR FLOW METER BURN-OFF (VOLTAGE LOW).
If burnoff is enabled, then halfway through the burnoff the voltageof the AFM sensor
is examined. If this voltage
<
2.2 volts then code 34 is set.
Note: If code 32 is also displayed then attend to that chart first.
Note: If battery voltage is not available at €CM pin 51, burn-off will not occur.
however
no code 34 will be set.
To force a burn-off.
Connect diagnostic plug, start engine. ECM lamp shows the state of the oxygen
sensor. Switch engine off and when engine stops switch ignition back
on again immediately.
Depress accelerator five times. The ECM lamp will be on when the accelerator
is depressed and off when the accelerator is released.
Remove the diagnostic plug. After the ignition is switched off, a forced burn-off
will occur under normal circumstances within ten seconds of switching
the ignition off.
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Continue measuring the air flow meter voltage (ECM pin 32)
when the ignition is switched off in the last step above.
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Repeat the force-a-burn-off procedure and
measure the voltage at connector AN38
while switching off the ignition.
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Less than 2.2 volts.
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for one second.
Repeat the force-a-burn-off procedure and
measure the air flow meter burn-off control
(Pin 4 of the AFM) while switching off the ignition.
connections in AN139,
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1
Less tha; 8 volts.
Less than 8 volts.
Check AN38 for
More than 8 volts
More than 8 volts
for 1 sec. after
ignition off.
Repeat force-a-burn-off
and measure ECM pin 38
while switching off ignition.
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volts for one
second after
for 1 second after
ignition off.
Check AN04 for open
or short circuits.
1
Disconnect airflow meter connector.
If ok replace ECM.
If ok, replace ECM.
repair loom.
Repeat force-a-burn-off and measure air flow
Check air flow meter relay for
faulty operation.
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Check for short or open circuit
in AN139.
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Clear codes, run engine for 2 minutes and re-check for codes.