1. Check the obvious (before diving into complex diagnostics):
* Battery voltage: A weak battery can sometimes prevent the ignition system from functioning properly. Use a multimeter to check the battery voltage while cranking. It should be above 10 volts. Low voltage indicates a weak or failing battery, or a charging system problem.
* Battery cables: Inspect the battery terminals and cables for corrosion, looseness, or damage. Clean them if necessary. A poor connection can interrupt the electrical flow.
* Fuses and relays: Check the fuses and relays related to the ignition system. Your owner's manual will show the fuse box layout. Pay close attention to those labeled "ignition," "fuel pump," "ECM" (Engine Control Module), and "crank sensor". A blown fuse or failed relay is a common culprit.
* Fuel: Although you say there's no spark, make sure you have fuel in the tank. An empty tank won't start the car even with a good spark.
2. Ignition System Components (in order of likelyhood):
* Crankshaft Position Sensor (CKP): This sensor tells the ECM where the crankshaft is in its rotation. Without this signal, the ECM won't allow a spark. A faulty CKP sensor is a very common cause of no-spark conditions. This sensor is relatively inexpensive and easy to replace.
* Cam Position Sensor (CMP): Similar to the CKP, the CMP sensor tells the ECM the position of the camshaft. A faulty CMP will prevent sparking.
* Ignition Control Module (ICM): The ICM receives signals from the sensors and the ECM, and controls the spark. A failing ICM is a frequent culprit for no spark. This is often harder to test at home.
* Ignition Coil(s): The coil(s) transform low voltage from the ICM into the high voltage needed to create a spark at the spark plugs. A failing coil will prevent spark to one or more cylinders. You can sometimes visually inspect for cracks in the coil. Testing requires a multimeter or a specialized coil tester.
* Spark Plugs and Wires: While less likely to cause a complete absence of spark, worn or damaged spark plugs or wires can prevent a spark. Inspect them for obvious damage. Replacing them isn't a bad idea anyway for routine maintenance on a car this age.
* Distributor (if applicable): If your Sebring has a distributor (some models did), check its cap and rotor for cracks, corrosion, or worn contacts. A faulty distributor can interrupt the spark.
3. Advanced Diagnostics:
* OBD-II Scanner: Use an OBD-II scanner (available at auto parts stores) to read any diagnostic trouble codes (DTCs) stored in the car's computer. These codes can provide valuable clues to the problem.
* Professional Mechanic: If you're not comfortable working on your car's electrical system, or after trying the above steps without success, it's best to take it to a qualified mechanic. They have the tools and expertise to diagnose the problem accurately and efficiently.
Important Safety Note: When working on your car's electrical system, always disconnect the negative (-) battery terminal to prevent accidental shorts and injuries.
By systematically checking these components, you should be able to pinpoint the cause of the no-spark condition in your 1998 Chrysler Sebring. Remember to start with the simplest checks and proceed to more complex ones only if necessary.
