Important Preliminary Inspections Before Starting
Before using this section, perform
Diagnostic System Check - Engine Controls
to verify the following items:
| • | The powertrain control module (PCM) and malfunction indicator lamp (MIL)
are operating correctly. |
| • | There are no DTCs stored. |
| • | Ensure that the engine coolant temperature (ECT) is not above 130°C
(266°F). This will cause the PCM to operate in the Engine Metal Overtemp Mode.
While in this state, the PCM will turn OFF four cylinders at a time to prevent the
engine coolant temperature from reaching damaging levels. Engine Metal Overtemp
can be perceived as a lack of power, engine miss, or rough idle. If the engine
is operating in the Engine Metal Overtemp mode, refer to DTC P1258. |
| • | Verify the customers complaint to reference the correct symptom table. |
Visual/Physical Inspection
Several of the symptom procedures call for a careful Visual/physical inspection.
This inspection can lead to correcting a problem without further inspections and
can save valuable time. This inspection includes the following items:
| • | Vacuum hoses for splits, kinks, proper routing, and connections--
Refer to the Vehicle Emission Control Information label. Check thoroughly for any
type of leak or restriction. Refer to
Emission Hose Routing Diagram
. |
| • | Intake air system for the following conditions: |
| - | A dirty or damaged air cleaner element or housing |
| - | Any damaged or collapsed intake air ducts |
| - | Any poor intake air system connections |
| • | Air leaks at the throttle body and/or intake manifold. |
| • | Throttle body contaminants or deposits. |
| • | Accelerator cable binding or damage. |
| • | Ignition system wiring for incorrect routing and/or poor connections. |
| • | System wiring for routing near high frequency devices (electromagnetic
interference (EMI) condition). |
The following Symptom tables are located in this section:
