Honda CRF450R 2009 Service Manual page 522

ELECTRICAL SYSTEM
TROUBLESHOOTING
Inspect the following before diagnosing the system.
- Faulty spark plug
- loose spark
plug
cap or spark
plug
wire connection
- Water gal into the spark plug cap (affecting the ignition coil secondary vol tage)
If
there is no spark at cylinder, temporarily exchange
the
ignition coil with a known good one, and perform the spark test. If there
is spark, the original ignition coil is faulty.
"Initial voltage" of the ignition primary coit is the battery voltage with the 12 V battery connected and lum the "ECM" selector
switch is ON . (The engine in not cranked
by
the kickstarter.)
No spark at plug
L
Ignition coil
primary
voltage
Unusual Condition
No initial voltage with the 12 V battery
connected and turn the -ECM-
selector switch is ON (Othereleclrical
components are normal).
h nilial I I
I
by 2 - 4 V while cranking the .n, , ,n •.
Probable Cause Check in numerical order
1. An open circuit in Black wire between the ignition coil and fuel
pump sub harness or regulator/rectifier.
2. loose or poor connection of the primary terminal, or an open
circuit in the primary coil.
, i
if vollage over the with reverse
connections).
2. Faulty CKP sensor (Measure peak voltage).
3. Faulty alternator (Measure the alternator coil resistance).
4. Faulty regulatorfrectifier (Check the wire harness and
regulator/rectifier).
5. Faulty ECM (in case when above No.1 through 4 are normal).
Initial voltage is
no~ rm ; ;;:O a'''b ~ U''I"'h~e~'. ~ i'''~n~ o -1-i1 .
Incorrect peak voltage adaptor connections (System is normal
peak voltage while cranking the if measured voltage is over the specifications with reverse
engine. connections).
2. Faulty peak voltage adaptor.
3. Faulty engine stop switch (Check the engine stop switch
operation).
4. An open circuit or loose connection in ground wire (,09· '12:
Green, After '12: Greenlwhite) at the ECM.
5. An open circuit or loose connection in Yellowfblue wire between
the i coil and ECM .
6. CKP sensor (Measure peak voltage).
7. alternator (Measure the alternator coil resistance).
8. . the wire harness and
,
,
i
2. Cranking speed is 100
"c'w
(Kickstarter is weak).
3. The sampling timing of the lester and measured pulse were not
synchronized (System is normal if measured voltage is over the
standard voltage at least once).
4. Faulty engine stop switch (Check the engine stop switch
operation).
5. Faulty alternator the alternator coil resistance).
6. i I wire harness and
~?W~~~~~~~~~ 7.
Inillal and peak voltages are normal 1.
bul no spark jumps. ampere.
2. Faulty ignition coil (Measure the resistance al the ignition coit
o.;;;;;:;;;;;-t--,
-;;;;;-;;;;;;"';;;;;;;;;;:--______ -t,~termjnals).
CKP sensor low peak voltage. 1. The multimeter impedance is too low; below 10 MO/DCV.
2. Cranking speed is too slow (Kickstarter is weak).
3. The sampling timing of the tester and measured pulse were not
synchronized. (System Is normal if measured voltage is over
the standard voltage at least once.)
4. Faulty CKP sensor {in case when above NO. 1 through 3 are
,-""c=~~c==-
_______
~-.~n~ o~rm~a~'~).~~~~~~~ _ _ _ _ _ _ _ _ _ _ _ _ ~
No peak voltage. 1. Faulty peak voltage adaptor.
2. Faulty CKP sensor.
17·6