P0193

DTC P0193

Circuit Description

The fuel rail pressure (FRP) sensor is a pressure sensor. The fuel injector control module (FICM) supplies about 5 volts on the FRP sensor reference voltage circuit. The FICM also supplies a ground circuit and a signal circuit to the FRP sensor. When the fuel rail pressure is normal, the FRP signal voltage rises to near 2.5 volts. If the fuel rail pressure increases, the FRP signal voltage increases. The FICM monitors the FRP sensor voltage and communicates the data to the PCM by a dedicated pulse width modulated (PWM) circuit.

This DTC sets when the FRP sensor signal voltage is more than the normal operating range of the sensor.

Conditions for Running the DTC

The ignition is ON.

Conditions for Setting the DTC

- The FRP sensor signal voltage is more than 5 volts.
- The condition exists for at least 5 seconds.

Action Taken When the DTC Sets

- The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
- The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the 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.
4. This step determines if an open sensor ground circuit condition the cause of the condition. The FRP and the FRT share a sensor ground. An open circuit between the splice and the FICM will cause both signal circuits to indicate a high voltage.
5. This step determines if an open or shorted signal circuit is the cause of the condition.
6. This step determines if a shorted 5-volt reference circuit is the cause of the condition.
7. This step determines if an open sensor ground circuit between the harness connector of the FRP sensor and the splice is the cause of the condition.