Toronado V6-231 3.8L (1986)
MASS AIR FLOW (MAF) SENSOR
FREQUENCY HIGH
Circuit Description:
The Mass Air Flow (MAF) sensor measures the amount of air which passes through it in a given time. The ECM uses this information to monitor the
operating condition of the engine, in calculating fuel delivery. A large quantity of air movement indicates acceleration, while a small quantity indicates
deceleration or idle. The MAF sensor produces a frequency signal which cannot be easily measured. The sensor can be diagnosed using the procedures
on this chart and with the aid of MAF sensor tester J-36101 or equivalent. Code E033 will set when the following conditions are met:
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E021 or E022 not present
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Engine is running at less than 800 RPM
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TPS is less than 500 mv
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Air Flow more than 150 grams per second
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All of the above are met for 5 seconds or more
Test Description:
The following numbered steps correspond with the step numbers on the diagnostic chart.
1.
The diagnostic display, ED21 (MAF), is of little use in diagnosing this fault, because when the code is set, a default based on TPS is displayed in
place of the actual MAF input to the ECM. If the Mass Air Flow Sensor fault is still present, Code E033 should reset within one minute. If the
code does not reset, the fault was intermittent and MAF Sensor tester J-36101 or equivalent should be used to test the sensor.
2.
Inspect wire routing of high voltage wires, such as spark plug wires. Such wires routed too closely to MAF wiring harness could possibly cause an
intermittent Code E033.
Diagnostic Aids:
An intermittent may be caused by a poor connection, rubbed through wire insulation or a wire broken inside the insulation.
Check For:
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Poor Connection or Damaged Harness: Inspect ECM harness connectors for backed out terminal "B6", improper mating, broken locks, improperly
formed or damaged terminals, poor terminal to wire connection and damaged harness.