Symptoms - Engine Controls

Symptoms - Engine Controls

Important Preliminary Checks Before Starting

Perform the Diagnostic System Check - Engine Controls Initial Inspection and Diagnostic Overview before using the symptom tables. Verify that all of the following conditions are true:

* The engine control module (ECM) and the malfunction indicator lamp (MIL) are operating correctly.
* There are no diagnostic trouble codes (DTCs) stored.
* The scan tool data is within the normal operating range. Refer to Scan Tool Data List Scan Tool Data List.

* Verify the customer concern and locate the correct symptom listed below. Inspect items indicated under that symptom.
* Several of the symptom procedures direct the technician to perform a visual/physical inspection. This important step can lead the technician to the cause of the problem without further checks and can save valuable time.
* Verify the correct installation and operation of electronic options, such as lights and cellular phones.

* Use the following tables when diagnosing a symptom concern:

* Hard Start Hard Start
* Surges/Chuggles Surges/Chuggles
* Lack of Power, Sluggishness, or Sponginess Lack of Power, Sluggishness, or Sponginess
* Detonation/Spark Knock Detonation/Spark Knock
* Hesitation, Sag, Stumble Hesitation, Sag, Stumble
* Cuts Out, Misses Cuts Out, Misses
* Poor Fuel Economy Poor Fuel Economy
* Rough, Unstable, or Incorrect Idle and Stalling Rough, Unstable, or Incorrect Idle and Stalling
* Dieseling, Run-On Dieseling, Run-On
* Backfire Backfire
* Malfunction Indicator Lamp (MIL) Inoperative Malfunction Indicator Lamp (MIL) Inoperative
* Malfunction Indicator Lamp (MIL) Always On Malfunction Indicator Lamp (MIL) Always On

* If the condition cannot be isolated using the appropriate table, refer to Intermittent Conditions Intermittent Conditions for further diagnosis.