P0206

DTC P0201-P0208

Circuit Description

The Alternative Fuels ECM enables the appropriate fuel injector on the intake stroke for each cylinder. An ignition voltage is supplied to the fuel injectors through a fuel injector relay. The Alternative Fuels ECM controls each fuel injector by grounding the control circuit via a solid state device called a driver. The Alternative Fuels ECM monitors the status of each driver. If the Alternative Fuels ECM detects an incorrect voltage for the commanded state of the driver, a fuel injector control DTC sets.


Conditions for Running the DTC

The engine is operating on CNG.


Conditions for Setting the DTC

* The Alternative Fuels ECM detects an incorrect voltage on a fuel injector control circuit.
* The condition exists for 5 seconds.



Action Taken When the DTC Sets

* The Alternative Fuels ECM illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.
* The Alternative Fuels ECM records the operating conditions at the time the diagnostic fails. The Alternative Fuels ECM stores this information in the Freeze Frame and/or Failure Records.
* The Alternative Fuels ECM will switch over to gasoline operation (KL6).



Conditions for Clearing the MIL/DTC

* The Alternative Fuels ECM turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
* A last test failed, or current DTC, clears when the diagnostic runs and does not fail.
* A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
* Use a scan tool in order to clear the MIL and the DTC.



Diagnostic Aids

* Performing the Fuel Injector Coil test may help isolate an intermittent condition. Refer toFuel Injector Coil Test (Component Tests and General Diagnostics) .
* For an intermittent condition, refer toIntermittent Conditions (Initial Inspection and Diagnostic Overview) .



Test Description

The numbers below refer to the step numbers on the diagnostic table.
2. This step verifies that the condition is present
4. This step determines if the condition affects an entire bank of the engine. The cylinder pairings are 1, 3, 5, 7, and 2, 4, 6, 8.
5. This step tests for voltage at the fuel injector harness connector. The fuel injector relay supplies power to the coil side of the fuel injector harness connector.
6. This step verifies that the Alternative Fuels ECM is able to control the fuel injector. If the test lamp blinks, then the Alternative Fuels ECM and wiring are OK.
7. This step tests if a ground is constantly being applied to the fuel injector.
10. This step tests for voltage at the fuel injector relay coil. The IGN E fuse supplies power to the coil side of the fuel injector relay. If the fuse is open, a short to ground on the ignition supply circuit is indicated.
11. This step tests for voltage at the fuel injector relay switch. If the fusible link is open, a short to ground on the B+ supply circuit is indicated.
12. This step tests the ground circuit of the fuel injector relay. If the test lamp does not illuminate, repair the open circuit.