Actron SunPro CP7678 - Ignition Coil Switching Action

250V MAX
15A MAX
FUSED
COM
DC
15A
20M
200
K
20K
2K
200
8CYL
6CYL
TACH
X10
5CYL
4CYL
8CYL
OHMS
15
A
Ignition Coil Switching Action
25
This test checks to see if the negative termi-
nal of the primary ignition coil is getting
switched ON and OFF via the ignition module
and camshaft / crankshaft position sensors.
This switching action is where the RPM or
tach signal originates. This test is primarily
used for a no start condition.
Fig. 28
Typical
Ignition
Coil
Ground
Black
Red
Test Procedure (see Fig. 28):
1. Insert BLACK test lead into COM test
lead jack.
2. Insert RED test lead into
test
lead jack.
3. Connect RED test lead to TACH signal
wire.
• If vehicle is DIS (Distributorless Ignition
System), then connect RED test lead to
the TACH signal wire going from the DIS
module to the vehicle engine computer.
(refer to vehicle service manual for loca-
tion of this wire)
• For all vehicles with distributors, connect
RED test lead to negative side of primary
ignition coil. (refer to vehicle service
manual for location of ignition coil)
4. Connect BLACK test lead to a good
vehicle ground.
5. Turn multimeter rotary switch to cor-
rect CYLINDER selection in LO TACH.
6. View reading on display while engine is
cranking.
• Typical cranking RPM range is 50-275
RPM depending on temperature, size of
engine, and battery condition.
• Refer to vehicle service manual for spe-
cific vehicle cranking RPM range.
7. Test Results.
Good Coil Switching Action: Display read-
ing indicated a value consistent with manu-
facturers specifications.
Bad Coil Switching Action:
• Display read zero RPM, meaning the
ignition coil is not being switched ON
and OFF.
• Check ignition system for wiring defects,
and test the camshaft and crankshaft
sensors.