250V MAX
15A MAX
FUSED
COM
DC
15A
20M
200
K
20K
2K
200
8CYL
6CYL
TACH
X10
5CYL
4CYL
8CYL
OHMS
15
A
Magnetic Pick-Up Coils – Reluctance Sensors
24
Reluctance sensors are used whenever the
vehicle computer needs to know speed and
position of a rotating object. Reluctance sen-
sors 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 the reluctance
sensor for an open or shorted coil. This test
does not check the air gap or voltage output of
the sensor.
Fig. 27
Reluctance
Sensor
Red
Black
Test Procedure (see Fig. 27):
1. Insert BLACK test lead into COM test
lead jack.
2. Insert RED test lead into
test
lead jack.
Reluctor
Ring
Magnet
3. Connect RED test lead to either sensor
pin.
4. Connect BLACK test lead to remaining
sensor pin.
5. Turn multimeter rotary switch to 2K
Ω
range.
6. View reading on display while flexing
sensor wires in several places.
• Typical resistance range is 150 - 1000
Ω
.
• Refer to vehicle service manual
for your vehicles resistance range.
• As you flex sensor wires, the dis-
play should remain steady.
7. Test Results
Good Sensor:
Display reading is
within manufacturers specification
and remains steady while sensor
wires are flexed.
Bad Sensor:
Display reading errati-
cally changes as sensor wires are
flexed or display reading is not within
manufacturers specification.