Important Preliminary Checks 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)
(Service Engine Soon) 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
in Engine Cooling. |
| • | Verify the customers complaint to reference the correct symptom table. |
Visual/Physical Check
Several of the symptom procedures call for a careful Visual/physical check.
This check can lead to correcting a problem without further checks and can save
valuable time. This check 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: |
| - | Dirty or damaged air cleaner element or housing |
| - | Damaged or collapsed intake air ducts. |
| - | 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:
