Your Chevrolet Monte Carlo may be experiencing engine problems, such as stalling, misfiring, knocking or poor acceleration. Troubleshooting the Monte Carlo's engine can mean searching under the hood, but for every symptom, there can be a couple of causes, and some parts of the engine can be hard to access. The Monte Carlo has an On-Board Diagnostic system. Using it can significantly cut down on the time spent troubleshooting the problem. However, how you use the OBD system depends on when your Monte Carlo was manufactured.
Open the driver's side door and locate the Monte Carlo's Data Link Connection. The DLC is the gateway to all of the Monte Carlo' s diagnostic system. It will either be black or gray in color and has 16 receiving slots. It will be in the general vicinity of the left kick panel beneath the dash.
Hook an OBD-II scanner into the DLC. Turn the scanner on if the model you have does not come on automatically.
Insert your key into the Monte Carlo's ignition and turn it to the "Accessories" position. Some scanners may require that the engine is cranked. If you own one of these scanners, crank the engine.
Press the appropriate button to retrieve the OBD-II codes. You will have to do this if your brand of scanner does not automatically scan the system upon sensing a connection with the Monte Carlo's computer.
Consult the scanner's manual for OBD-II coding and code definitions. It will likely contain the generic OBD-II codes universal to all post-1996 vehicles. General Motors has supplemental codes, which you will need to look up online. Your Monte Carlo's manual will not have these codes.
Make a list of the codes and prioritize them. All trouble codes should be investigated first. These have occurred more frequently, causing the "Check Engine" light on the Monte Carlo's dash to illuminate. Next, write down all of the pending codes. These are problems that have occurred but not with the frequency of trouble codes. These codes could be trending toward trouble status.
Turn off the Monte Carlo and remove the key from the ignition. Unplug the scanner from the DLC outlet. Open the engine compartment, and use your list of codes and definitions for further troubleshooting.
Locate the Assembly Line Diagnostic Link. The ALDL is a 12-slot outlet located beneath the steering column.
Bend a paperclip into a "U." Locate two slots at the end of the ALDL's top row of slots. These are next to each other to the far right. Insert the ends of the "U" into the two slots.
Insert your key into the Monte Carlo's ignition and turn it on but do not crank the engine.
Count how many times the "Check Engine" light flashes. General Motors' flash codes are two-digit numbers. The first number will be a long flash, and the second will be a short flash. There will be a pause between the end of a code and the beginning of another. Code 12 will appear at the beginning of the flashing sequence. Ignore this as this is common and does not correspond with an engine problem.
Write the code numbers down. Consult an online list of GM flash codes for definitions. Turn the Monte Carlo off. Open the engine compartment and use the list to focus your investigation.
