What will cause the 2006 Chevy Cobalt 2.2 ls not to run turns over start check engine light is on?

A 2006 Chevy Cobalt 2.2L LS that cranks but won't start with the check engine light on could have several causes. The key is to get the diagnostic trouble codes (DTCs) read from the car's computer. This is best done with an OBD-II scanner; auto parts stores often offer free code reading services. The codes will pinpoint the problem much more accurately than guesswork.

However, some common possibilities include:

* Crank Position Sensor (CKP) or Cam Position Sensor (CMP): These sensors tell the computer the position of the crankshaft and camshaft. If faulty, the computer won't know when to fire the spark plugs, resulting in a no-start condition. This is a very common culprit in no-start situations.

* Mass Airflow Sensor (MAF) Sensor: A faulty MAF sensor provides inaccurate air intake readings, causing the computer to adjust the fuel mixture incorrectly. While it might not completely prevent starting, it could lead to a rough running condition or failure to start.

* Fuel System Issues:

* Fuel Pump: A weak or failing fuel pump might not supply enough fuel pressure to the engine.

* Fuel Filter: A clogged fuel filter can restrict fuel flow.

* Fuel Injectors: Clogged or faulty injectors prevent fuel from reaching the cylinders.

* Ignition System Problems:

* Ignition Coil: A failing ignition coil can prevent spark to one or more cylinders.

* Spark Plugs/Wires: Worn, damaged, or fouled spark plugs or wires can prevent proper ignition.

* Throttle Position Sensor (TPS): A faulty TPS can give the computer inaccurate throttle position information, leading to starting problems.

* Computer (PCM) Problems: Though less common, a faulty PCM can prevent the engine from starting.

Troubleshooting Steps (Beyond getting the codes):

1. Check for obvious problems: Look for loose or damaged wires, particularly around the ignition system and sensors.

2. Check the fuel pressure: This usually requires a fuel pressure gauge. Low fuel pressure indicates a problem with the fuel pump, filter, or pressure regulator.

3. Inspect the spark plugs: Check their condition – are they fouled, worn, or damaged?

4. Check for power at the fuel pump: A simple voltage test can determine if the pump is receiving power.

In short: Getting the DTCs is the crucial first step. Take your car to an auto parts store or a mechanic to get them read. This will give you a much clearer picture of the problem and avoid unnecessary parts replacement.