Honda SH300 2006 Manual page 115

PGM-FI SYMPTOM TROUBLESHOOTING
When the scooter has one of these symptoms, check the DTC or MIL blinking, refer to the DTC index (page 6-15) and begin
the appropriate troubleshooting procedure. If there are no DTC/MIL blinking stored in the ECM memory, do the diagnostic
procedure for the symptom, in sequence listed below, until you find cause.
Symptom
Engine cranks but won't
start
(No fuel pump operation
sound when the turning the
ignition switch "ON")
Engine cranks but won't
start
(No DTC and MIL blinking)
Engine stalls, hard to start,
rough idling
Afterburn when engine
braking is used
Backfiring or misfiring dur-
ing acceleration
Poor performance (drive-
ability) and poor fuel econ-
omy
Idle speed is below specifi-
cations or fast idle too low
(No DTC and MIL blinking)
Idle speed is above specifi-
cations or fast idle too high
(No DTC and MIL blinking)
MIL never comes ON at all
MIL stays ON at all
(No DTC set)
Diagnosis procedure
1. ECM power/ground circuits
malfunction (page 6-65)
2. Inspect the fuel pump (page 6-
48)
1. Crank the starter for more than
ten seconds and check the DTC
(page 6-15) and execute the
troubleshooting according to
the DTC.
2. Inspect the IACV (page 6-77).
3. Inspect the ignition system
(page 20-5).
1. Inspect the idle speed
(page 6-77)
2. Inspect the IACV (page 6-77)
3. Inspect the fuel supply system
(page 6-44).
4. Inspect the ignition system
(page 20-5).
1. Inspect the PAIR system
(page 6-78).
2. Inspect the ignition system
(page 20-5).
Inspect the ignition system (page
20-5)
1. Inspect the fuel supply system
(page 6-44)
2. Inspect the ignition system
(page 20-5).
1. Inspect the idle speed
(page 6-77)
2. Inspect the IACV (page 6-77)
3. Inspect the fuel supply system
(page 6-44)
4. Inspect the ignition system
(page 20-5)
1. Inspect the idle speed
(page 6-77)
2. Inspect the throttle operation
and grip free play
3. Inspect the IACV (page 6-77)
Inspect the MIL circuit (page 6-43).
1. Inspect the MIL circuit (page 6-
43)
2. Inspect the DLC circuit (page 6-
43)
FUEL SYSTEM (PGM-FI)
Also check for
• Faulty bank angle sensor or related circuit
• Faulty engine stop relay or related circuit
• Faulty sensor unit or related circuit
• Faulty ECM
• No fuel to injector
– Clogged fuel filter
– Pinched or clogged fuel feed hose
– Pinched or clogged fuel tank breather
hose
– Faulty fuel pump
• Intake air leak
• Contaminated/deteriorated fuel
• Faulty fuel injector
• Restricted fuel feed hose
• Contaminated/deteriorated fuel
• Intake air leak
• Restricted fuel tank breather tube
• Pinched or clogged fuel feed hose
• Faulty pressure regulator in the fuel pump
• Faulty injector
• Intake air leak
• Engine top end problem
• Air cleaner condition
6-5