3-2
Vehicle Testing
Exhaust System
•
Exhaust pipes and connections
— Connections should be tight and with no obvious leaks or
obstructions.
•
Catalytic converter
•
Air management system
— Check valves should not leak.
•
Diverter valve/air switching valve
— Valve should not stick or leak into closed off port.
Electrical System
•
Wiring
— Check for proper connections, pinches, cuts, corrosion, etc.
•
Engine/power control module grounds and sensors
— Ensure that all are clean, tight, and in their proper location.
•
Cranking system circuits
•
Charging system circuits
•
Ignition system circuits
— Check ignition wires for cracking, hardness, proper routing
and carbon tracking.
•
Fuel system
•
Battery
— Check state of charge, general condition and connections.
Basic Engine Functions
•
Engine timing
•
Idle speed
•
Air leaks
— Check throttle body mounting area and intake manifold
sealing surfaces.
•
Fuel feedback system
Verify the Customer Complaint
Perform On-Board Diagnostic (OBD) checks before attempting to
analyze data collected for diagnosing a driveability or emissions
complaint. Determine that:
•
Engine/power control module and check engine or malfunction
indicator lamp (MIL) operates correctly, and
•
No diagnostic trouble codes (DTC) are stored.
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