P1020

DTC P1020

Circuit Description

The PCM controls fuel delivery and determines fuel system operation on Bi-fuel (KL6) vehicles. The PCM is not capable of operating the high current CNG fuel injectors. The PCM injector pulse width (PWM) signals are received by the fuel injector control module (FICM) and duplicate PWM signal are generated by the FICM in order to operate the CNG injectors. Ignition voltage is supplied to the fuel injectors. The FICM controls each CNG fuel injector by grounding the control circuit via a solid state device called a driver. The FICM monitors the status of each driver. If the control module detects an incorrect voltage for the commanded state of the driver, a fuel injector control DTC sets.

Conditions for Running the DTC

The ignition is ON.

Conditions for Setting the DTC

- The fuel injector control module (FICM) detects an incorrect voltage on a CNG fuel injector control circuit.
- The condition exists for 5 seconds.

Action Taken When the DTC Sets

- The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.
- The control module switches over to gasoline fuel operation.
- The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame/Failure Records.

Conditions for Clearing the MIL/DTC

- The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
- A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
- A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
- Clear the MIL and the DTC with a scan tool.

Diagnostic Aids

- Performing the Fuel Injector Coil Test may help to isolate an intermittent condition.
- For an intermittent condition, refer to Intermittent Conditions.

Test Description

The numbers below refer to the step numbers on the diagnostic table.

5. This step verifies that the FICM is able to control the fuel injector.
6. This step tests if a ground is constantly being applied to the fuel injector.