Operating instructions

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3. Disconnect wiring harness and vacuum
line from MAP sensor.
4. Connect jumper wire between Pin A on
wiring harness and sensor.
5. Connect another jumper wire between
Pin C on wiring harness and sensor.
6. Connect RED test lead to sensor Pin B.
7. Connect BLACK test lead to good ve-
hicle ground.
8. Make sure test leads and jumper wires
are not touching each other.
9. Connect a hand held vacuum pump to
vacuum port on MAP sensor.
10.Turn Ignition Key ON, but do not start
engine!
11.Turn multimeter rotary switch to...
• 20V range for DC type MAP sensors.
• 4 Cylinder TACH position for Frequency
type MAP sensors.
12.View reading on display.
DC Volts Type Sensor:
• Verify hand held vacuum pump is at 0 in.
of vacuum.
• Display reading should be approximately
3V or 5V depending on MAP sensor
manufacturer.
Frequency Type Sensor:
• Verify hand held vacuum pump is at 0 in.
of vacuum.
• Display reading should be approximately
4770RPM ± 5% for Ford MAP sensors
only.
• For other frequency type MAP sensors
refer to vehicle service manual for MAP
sensor specifications.
• It is O.K. if last two display digits change
slightly while vacuum is held constant.
• Remember to multiply display reading by
10 to get actual RPM.
• To convert RPM to Frequency or vice
versa, use equation below.
Frequency =
RPM
30
(Equation Only Valid for Multimeter in 4
Cylinder HI/LO TACH Position)
13.Operate Sensor.
• Slowly apply vacuum to MAP sensor -
Never exceed 20 in. of vacuum because
damage to MAP sensor may result.
• Display reading should decrease in
volt-
age or RPM as vacuum to MAP sensor
is increased.
• Refer to vehicle service manual for charts
relating voltage and frequency drop to
increasing engine vacuum.
• Use equation above for Frequency and
RPM conversions.
14.Test Results.
Good Sensor:
• Sensor output voltage or frequency(RPM)
are within manufacturers specifications
at 0 in. of vacuum.
• Sensor output voltage or frequency
(RPM) decrease with increasing vacuum.
Bad Sensor:
• Sensor output voltage or frequency
(RPM) are not within manufacturers
specifications at 0 in. of vacuum.
• Sensor output voltage or frequency
(RPM) do not change with increasing
vacuum.