Download Description The Engine Cranks but Does Not Run diagnostic table assumes that the battery condition and the engine cranking speed are OK. If the battery condition and the cranking speed are not OK, refer to Diagnostic System Check – Engine Electrical in Engine Electrical for diagnosis. Make sure that there is adequate fuel in the fuel tanks. Diagnostic Aids • Check the duct work between the mass air flow (MAF) sensor and the throttle body for air leaks. • A malfunctioning MAF sensor may cause a no start or a stall after start. If you suspect this, disconnect the MAF sensor. The powertrain control module (PCM) will default to the speed density in order to calculate the load and the air flow. If this corrects the condition and the connections are OK, replace the MAF sensor. If the steps above check OK, refer to Symptoms . Test Description The numbers below refer to the step numbers on the diagnostic table. 4. It may be necessary to connect a battery charger to the battery for this step. If the battery state of charge is low, the scan tool may reset during the cranking test. 5. This step tests the ignition relay for proper operation. The ignition relay supplies voltage to the injectors and the ignition coils. When the ignition relay is not operating properly, a no start condition occurs. If the test lamp does not illuminate, this indicates the ignition relay is not suppling a voltage to the fuses.