Symptoms - Engine Controls

Symptoms - Engine Controls

Important Preliminary Checks Before Starting

Perform the Diagnostic System Check - Engine Controls Diagnostic System Check - Engine Controls 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.

1. 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

* Engine Cranks But Does Not Run Engine Cranks but Does Not Run

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