Faulty Fuel Injector 4
Fuel Injector 4 harness is open or shorted
Fuel Injector 4 circuit poor electrical connection
Faulty Engine Control Module (ECM)
Engine Light ON (or Service Engine Soon Warning Light)
The Engine Control Module (ECM) supplies voltage to each fuel injector on the high control circuits. The ECM energizes each fuel injector by grounding the low control circuit of the fuel injector. The ECM monitors the status of the fuel injector circuits. When a fuel injector circuit condition is detected by the ECM, the affected fuel injector(s) is disabled. The Diagnostic Trouble Code (DTC) will be set when the ECM detects the fuel injector high voltage supply circuit is not to factory specifications.