Diagnostic Aids

Test procedures are intended to identify faulty components or wiring while fault is present. If complaint is an intermittent condition, refer to H - TESTS W/O CODES article or perform CIRCUIT TEST Z under CIRCUIT TESTS in appropriate G - TEST W/CODES article.

1. Check For Diagnostic Trouble Codes (DTC)
   
   Perform QUICK TEST in appropriate G - TEST W/CODES article. If DTCs are present, service DTCs. See appropriate CIRCUIT TEST under CIRCUIT TESTS in appropriate G - TEST W/CODES article. If DTCs are not present, go to next step.
2. Check Battery
   
   Turn ignition on. Check battery voltage. If battery voltage is less than 12 volts, service battery as necessary and check charging system. If battery voltage is more than 12 volts, go to next step.
3. Check For Spark
   
   Using Spark Tester (D81P-6666-A or D89P-6666-A), check for spark at each spark plug wire or coil while cranking. If spark is consistent at all spark plug wires, go to next step. If spark is not consistent, go to CIRCUIT TEST JD under CIRCUIT TESTS in appropriate G - TEST W/CODES article to test crankshaft position sensor.
4. Check Spark Plugs
   
   Remove and inspect spark plugs. Replace plugs as necessary. If spark plugs are okay, testing is complete. If fault is still present, go to CIRCUIT TEST H under CIRCUIT TESTS in appropriate G - TEST W/CODES article. If vehicle has a no-start condition, go to CIRCUIT TEST A under CIRCUIT TESTS in appropriate G - TEST W/CODES article.