Suzuki 2000 Grand Vitara SQ625 Service Manual page 73

TROUBLESHOOTING (DTC P0300/P0301/P0302/P0303/P0304)
STEP
1 Was "ENGINE DIAG. FLOW TABLE" performed?
2 Ignition System Inspection:
1) Check spark plug and ignition spark of cylinder
where misfire occurs, referring to "IGNITION
SYSTEM" section.
Is it in good condition?
3 Fuel Injector Circuit Inspection:
1) Using sound scope, check each injector
operating sound at engine cranking or idling.
Do all injectors make operating sound?
4 Fuel Pressure Inspection:
1) Check fuel pressure referring to TABLE B-3 in
this section.
Is check result satisfactory?
5 Fuel Injector Inspection:
1) Check fuel injector(s) referring to "ENGINE AND
EMISSION CONTROL SYSTEM" section.
Is check result satisfactory?
6 Ignition Timing Inspection:
1) Check ignition timing referring to "IGNITION
SYSTEM" section.
Is check result satisfactory?
7 EGR System Inspection:
1) Check EGR system referring to "ENGINE AND
EMISSION CONTROL SYSTEM" section.
Is check result satisfactory?
8 Fuel Level Sensor Inspection:
1) Check fuel level sensor referring to DTC P0461
Diag. Flow Table.
Is check result satisfactory?
9 Check engine mechanical parts or system which
can cause engine rough idle or poor performance.
– Engine compression (See "ENGINE
MECHANICAL" section).
– Valve lash or lash adjuster (See "ENGINE
MECHANICAL" section).
– Valve timing (Timing belt or chain installation.
See "ENGINE MECHANICAL" section).
Are they in good condition?
ACTION
ENGINE DIAGNOSIS (G16 / J20 ENGINES) 6-69
YES
Go to Step 2.
Go to Step 3.
Go to Step 4.
Go to Step 5.
Go to Step 6.
Go to Step 7.
Go to Step 8.
Go to Step 9.
Check wire harness
and connection of
ECM (PCM) ground,
ignition system and
fuel injector for
intermittent open
and short.
NO
Go to "ENGINE
DIAG. FLOW
TABLE".
Faulty ignition coil,
wire harness, or other
system parts.
Check coupler
connection and wire
harness of injector not
making operating
sound and injector
itself.
If OK, substitute a
known-good ECM
(PCM) and recheck.
Repair or replace.
Replace.
Adjust or check
system related parts.
Repair or replace.
Repair or replace.
Repair or replace.