Actron Digital Multimeter CP7676 - Manual (Page 23)

9V
4
CYL 5
CYL
6
CYL
8
CYL
2K 200
200
750
20
2
20M
2M
200K
20K
OHMS
RPM
X10
750V AC
200V DC
COM V
DWELL
4
CYL
5
CYL
6
CYL
8
CYL
23
Hall Effect Sensors/Switches
Hall Effect sensors are used whenever the
vehicle computer needs to know speed and
position of a rotating object. Hall Effect
sensors are commonly used in ignition
systems to determine camshaft and
crankshaft position so the vehicle computer
knows the optimum time to fire the ignition
coil(s) and turn on the fuel injectors. This test
checks for proper operation of the Hall Effect
sensor / switch.
Test Procedure (see Fig. 23):
1. Remove Hall Effect Sensor from
vehicle.
Refer to vehicle service manual for
procedure.
2. Connect 9V battery to sensor POWER
and GROUND pins.
• Connect positive(+) terminal of 9V
battery to sensor POWER pin.
• Connect negative(-) terminal of 9V
battery to sensor GROUND pin.
• Refer to illustrations for POWER and
GROUND pin locations.
• For sensors not illustrated refer to
vehicle service manual for pin locations.
3. Insert BLACK test lead into the COM
test lead jack.
4. Insert RED test lead into the
V
test
lead jack.
5. Connect RED test lead to sensor
SIGNAL pin.
6. Connect BLACK test lead to 9V battery
negative (-) pin.
7. Turn multimeter rotary switch to 200 Ω
range.
Multimeter display should read a small
ohm value.
8. Slide a flat blade of iron or magnetic
steel between sensor and magnet. (Use
a scrap of sheet metal, knife blade, steel
ruler, etc.)
• Multimeter display should indicate an
overrange condition.
• Remove steel blade and multimeter
should again display a small ohm value.
• It is O.K. if display changes erratically
after steel blade is removed.
• Repeat several times to verify results.
9. Test Results.
Good Sensor: Display reading toggles
from a small ohmic value to an overrange
condition as steel blade is inserted and
removed.
Bad Sensor: Display reading remains
unchanged as steel blade is inserted and
removed.
Fig. 23
Jumper
Wires
Sensor
POWER
SIGNAL
GROUND
Black
Typical Hall
Effect Sensor
Chrysler Distributor
Hall Effect
POWER
GROUND SIGNAL
Magnet
Iron or
Steel Blade
Red
GROUND
Ford Distributor
Hall Effect
POWER
SIGNAL