- Symptoms - Engine Controls

Symptoms - Computer and Control System

Important Preliminary Inspections Before Starting

Before using this section, perform the Diagnostic System Check - Vehicle and verify all of the following conditions: Initial Inspection and Diagnostic Overview

* The engine control module (ECM) and the malfunction indicator lamp (MIL) are operating correctly.
* There are no 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. Inspect the items indicated under that symptom.
* Several of the symptom procedures ask for a careful visual/physical inspection. This step is extremely important, and can lead to correcting a condition without further inspections and can save valuable time.
* If an intermittent condition exists as a start and then a stall, inspect for any DTCs related to the theft deterrent system. Refer to Diagnostic Trouble Code (DTC) List - Vehicle. Diagnostic Trouble Code Descriptions
* Verify the proper installation of any of the following non-original equipment accessories:

- Lights
- Cellular phone
- Remote starter system
- Non-factory installed alarm.

1. Use the tables when diagnosing a symptom concern:

* Hard Start
* Surges/Chuggles
* Lack of Power, Sluggishness, or Sponginess
* Detonation/Spark Knock
* Hesitation, Sag, Stumble
* Cuts Out, Misses
* Poor Fuel Economy
* Poor Fuel Fill Quality
* Rough, Unstable, or Incorrect Idle and Stalling
* Dieseling, Run-On
* Backfire

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