Suzuki Engine 2002 GRAND VITARA SQ625, Service Manual

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ENGINE GENERAL INFORMATION AND DIAGNOSIS (H25 ENGINE) 6-1-35
Engine Diagnosis Table
Perform troubleshooting referring to following table when ECM (PCM) has detected no DTC and no abnormality
has been found in visual inspection and engine basic inspection previously.
Condition Possible Cause Correction
Hard starting
(Engine cranks
OK.) Engine and emission control system out of
order.
• Faulty idle air control system
“DTC P0505 Diag. Flow Table” in this sec-
tion.
• Faulty ECT sensor or MAF sensor “ECT sensor” or “MAF sensor” in Section
6E2.
• Faulty ECM (PCM) “Inspection of ECM (PCM) and Its Circuit” in
this section.
Low compression. “Compression Check” in Section 6A2.
• Faulty hydraulic valve lash adjuster “Camshaft and Valve Lash Adjuster” in Sec-
tion 6A2.
• Compression leak from valve seat “Valves and Cylinder Heads” in Section
6A2.
• Sticky valve stem “Valves and Cylinder Heads” in Section
6A2.
• Weak or damaged valve springs “Valves and Cylinder Heads” in Section
6A2.
• Compression leak at cylinder head gas-
ket
“Valves and Cylinder Heads” in Section
6A2.
• Sticking or damaged piston ring “Piston, Piston Rings, Connecting Rods and
Cylinders” in Section 6A2.
• Worn piston, ring or cylinder “Piston, Piston Rings, Connecting Rods and
Cylinders” in Section 6A2.
Others
• Malfunctioning PCV valve
“PCV System” in Section 6E2.