Test Preliminary Checks

Most driveability problems in the engine control system result from faulty or poor wiring, or loose and/or leaking hose connections. To avoid unnecessary component testing, a visual check should be performed before beginning trouble shooting procedures to help spot these common faults. A preliminary visual check should include the following:

• Air ducts to air cleaner and from air cleaner to throttle body.
• Electrical connections at all components should be clean, tight and unbroken.

Check all vacuum lines for secure, leak-free connections in the following areas:

• Throttle body (2 front, 2 rear).
• EGR, purge, wastegate and barometric read solenoids (located on a common bracket on turbo models, at right rear corner of engine compartment).
• Vapor canister.
• Vacuum source and fuel pressure regulator.
• PCV valve and turbocharger.
• PCV valve to intake manifold vacuum port.
• Back pressure transducer.
• MAP sensor.

Also ensure that the following electrical connectors are securely attached:

• 25-way connectors (2  ) at logic module (Connectors and sockets are color coded. Attach Black and White connectors (non-turbo) or Red and Blue connectors (turbo) to sockets of same color).
• 3-way and 1-way connectors at ASD Relay.
• 12-way and 10-way connectors at power module.
• 2-way connector at purge solenoid (non-turbo).
• 4-way and 1-way connector at solenoids (turbo).
• 2-way connector at distance/speed sensor (located in line with speedometer cable).
• 2-way connector at charge temperature sensor (turbo only).
• 6-way connector at AIS motor and TPS (and ground wire to manifold).
• 2-way connector at fuel injector (non-turbo) or at each of 4 fuel injectors (turbo).
• O2 connector.
• 2-way connector at coolant temperature sensor.
• 3-way connector at distributor.
• 3-way connector at distributor synchronizer (turbo only).
• 3-way or 4-way and 1-way connectors at radiator fan relay.