The injector system on both SOHC and DOHC engines utilize sequential fuel injection (SFI). the powertrain control module (PCM) independently controls each fuel injector through a driver circuit, in accordance with intake valve openeing. The driver circuit is intentionally located in the PCM providing the ground for each injector. The length and time an injector is held open, grounded by the PCM, is calculated based on engine speed load and valve location fron the crankshaft position sensor.

DTC P0201 Injector 1, or DTC P0202 Injector 2, or DRC P0203 Injector 3 orDTC P0204 Injector 4 will set if an injector circuit is open, shorted to voltage, or shorted to ground.

Important: The injector circuit is continuously checked when the engine is running.

When attempting to diagnose an intermittent problem use the scan tool to eview the malfunction history diagnostic information. This supplemental data can be used to duplicate a problem.

Imntermittents or opens suspected to be at the connector can be detected by using a diagnostic service probe. Voltage can be read on wires without disconnecting any connectors.

Check the tightness of female terminal grip with a spare male terminal.

An open or shorted injector circuit will cause a misfire DTC to set. Diagnose an injector coe first if an injector and a misfire DTC occur.