P1207

DTC P1207

Circuit Description

The fuel injector control module (FICM) monitors the fuel rail pressure (FRP) sensor voltage, and the fuel rail temperature (FRT) sensor voltage. The FICM communicates the data to the PCM by dedicated pulse width modulated (PWM) circuits.

This DTC sets when the rail pressure output PWM signal is not received by the PCM.

Conditions for Running the DTC

The ignition is ON.

Conditions for Setting the DTC

- The rail pressure output PWM signal is not received by the PCM.
- The condition exists for at least 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.

Test Description

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

2. This step determines if the condition is present.
3. If any of the listed DTCs are set, diagnose those DTCs first.
5. This step determines if a FRP sensor circuit may be the cause of the condition. If a FRP sensor circuit condition exists, the FICM will output 0% PWM to the PCM. With the FRP sensor disconnected, the fuel rail pressure should slowly rise.
6. This step verifies that the FICM is supplying 5 volts on the FRP sensor reference circuit. An open, or a short to ground, on the 5 volt reference circuit may set this DTC.
7. This step verifies that the FICM is supplying a low reference circuit. An open on the FRP sensor low reference circuit may set this DTC.
8. This step determines if the signal circuit of the FRP sensor is shorted to a voltage. A short to a voltage on the signal circuit of the FRP sensor may set this DTC.
9. This step determines if the signal circuit of the FRP sensor is shorted to ground. A short to ground on the signal circuit of the FRP sensor may set this DTC. The DMM will display OL If the signal circuit is not grounded.
10. This step verifies that the FICM is supplying the correct output voltage on the FRP output PWM circuit. The open circuit voltage should be 5.0 volts.