Testing & Diagnosis Preliminary Checks: Notes
NOTE:
Information on this system is also covered in the FUEL SYSTEMS section. Additional diagnostic information that relates strictly to the fuel portion of this system can be found in the THROTTLE BODY FUEL INJ. article in the FUEL SYSTEMS section.
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:
- Air ducts to air cleaner and from air cleaner to throttle body.
- Electrical connections at all components. Clean, tight and unbroken.
Check 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.
- Backpressure transducer.
- MAP sensor.
Ensure that the following electrical connectors are clean and 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.