The fuel injection system on both SOHC and DOHC engines utilize sequential fuel injection. The PCM independently controls each fuel injector through separate internal drivers. The powertrain control module (PCM) drivers hold each fuel injector circuit to ground for a certain length of time based on engine operating parameters. The fuel control system is designed to maintain a 14.7:1 air/fuel ratio under all conditions except power enrichment mode (heavy acceleration/heavy engine load). The PCM monitors the fuel injector circuits for low and high voltage faults. DTC P0200 sets when the PCM has detected an intermittent open, short to ground or short to voltage in any of the four fuel injector circuits. This DTC is used when the PCM cannot distinguish which injector circuit has failed or the type of fault that occurred (e.g. open, short to ground or short to voltage) with the circuit because the length of time the fault condition existed was too short.
DTC Parameters
DTC P0200 will set if any one of the 4 fuel injector circuits is intermittently open, shorted to ground or shorted to voltage when engine is running.
This DTC will set when a fuel injector circuit fails for a very short amount of time, in which the PCM cannot detect which injector or which specific fault has occurred.
DTC P0200 diagnostic runs continuously with engine running.
DTC P0200 is a type D DTC.
Diagnostic Aids
If a specific fuel injector DTC is set, that circuit is most likely the cause of this DTC and should be diagnosed first.
To locate this intermittent problem, start engine and use scan tool to monitor INJECTORS 1-4 LOW VOLT, OPEN and HIGH VOLT tests. When an open or short to ground fault exists, the scan tool will display TEST FAIL for both the LOW VOLT and OPEN tests. When a short to voltage or shorted solenoid fault exists, the scan tool will display TEST FAIL for the HIGH VOLT test.
The LOW VOLT and OPEN tests will fail only when the device is being commanded OFF and the voltage at the PCM is low. The HIGH VOLT test will fail only when the device is being commanded ON and the voltage at the PCM is high. All 3 tests update every 100 ms.
The fuel injector resistance is 12.2 +/- 0.4 ohms at 23°C (74°F).
