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. |
| • | 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:
| • | PCM grounds for being clean, tight, and in the proper location. |
| • | 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. |
| • | 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). |
| • | Engine cooling system leaks. Refer to
Loss of Coolant
in Engine Cooling. |
The following Symptom tables are located in this section:
