Circuit Description
The fuel rail pressure sensor is installed to the fuel rail. The fuel rail pressure detects the fuel pressure in the fuel rail, converts the pressure into a voltage signal, and sends the signal to the engine control module (ECM). The fuel rail pressure sensor has the following circuits:
| • | A 5-volt reference circuit |
| • | A low reference circuit |
| • | A fuel rail pressure sensor signal circuit |
The ECM supplies 5 volts to the fuel rail pressure sensor on the 5-volt reference circuit. The ECM also provides a ground on the low circuit. Higher fuel rail pressure provides higher fuel pressure sensor voltage, while lower pressure provides lower fuel pressure sensor voltage. The ECM calculates the actual fuel rail pressure, fuel pressure, from the voltage signal, and uses the result in fuel injection control and other control tasks. The ECM monitors the fuel rail pressure sensor signal for voltage outside the normal range. If the ECM detects an excessively low fuel rail pressure sensor signal voltage, this DTC will set.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC P0192 Fuel Rail Pressure (FRP) Sensor Circuit Low Voltage
Conditions for Running the DTC
| • | The ignition switch is ON. |
| • | The battery voltage is between 10-16 volts. |
Conditions for Setting the DTC
The ECM detects that the fuel rail pressure sensor signal voltage is less than 0.7 volt.
Action Taken When the DTC Sets
| • | The ECM illuminates the malfunction indicator lamp (MIL) and Reduced Engine Power indicator lamp, if fitted, when the diagnostic runs and fails. |
| • | The ECM records the operating conditions at the time the diagnostic fails. The ECM stores this information in the Failure Records. |
| • | The ECM limits the fuel injection quantity for fail-safe operation. |
| • | The ECM closes the exhaust gas recirculation (EGR) valve and holds the EGR valve to a closed position. |
| • | The ECM limits the desired fuel rail pressure for fail-safe operation. |
| • | The ECM inhibits cruise control. |
Condition for Clearing the DTC
| • | A current DTC, Last Test Failed, clears when the diagnostic runs and passes. |
| • | Clear the MIL and the DTC with a scan tool. |
Step | Action | Values | Yes | No | ||||
|---|---|---|---|---|---|---|---|---|
Schematic Reference: Engine Controls Schematics | ||||||||
1 | Did you perform the Diagnostic System Check - Vehicle? | -- | Go to Step 2 | |||||
2 |
Is DTC P0641 also set? | -- | Go to DTC P0641 | Go to Step 3 | ||||
3 |
Did the DTC fail this ignition? | -- | Go to Step 4 | Go to Intermittent Conditions | ||||
4 |
Is the DMM voltage more than the specified value? | 4.6 V | Go to Step 5 | Go to Step 6 | ||||
5 |
Is the fuel rail pressure sensor parameter less than the specified value? | 181 MPa (26,293 psi) | Go to Step 6 | Go to Step 7 | ||||
6 |
Did you find and correct the condition? | -- | Go to Step 10 | Go to Step 8 | ||||
7 |
Did you find and correct the condition? | -- | Go to Step 10 | Go to Step 9 | ||||
8 | Replace the fuel rail pressure sensor. Did you complete the replacement? | -- | Go to Step 11 | -- | ||||
9 |
Important: The new ECM must be programmed. Replace the ECM. Refer to Engine Control Module Programming and Setup , Engine Control Module Replacement/Restore Fuel Rate Data , and Fuel Injector Flow Rate Programming . Did you complete the replacement? | -- | Go to Step 10 | -- | ||||
10 |
Did the DTC fail this ignition? | -- | Go to Step 2 | Go to Step 11 | ||||
11 | Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed? | -- | System OK | |||||
