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For 1990-2009 cars only
Makes 🢒 Isuzu 🢒 2007 🢒 Isuzu MD F-Series 🢒 Driver Information and Entertainment 🢒 Displays and Gages 🢒 DTC P0192

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?

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Go to Step 2

Go to Diagnostic System Check - Vehicle

2
  1. Install a scan tool.
  2. Monitor the DTC Information with a scan tool.

Is DTC P0641 also set?

--

Go to DTC P0641

Go to Step 3

3
  1. Observe the Failure Records for this DTC.
  2. Turn OFF the ignition for 30 seconds.
  3. Start the engine.
  4. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records.

Did the DTC fail this ignition?

--

Go to Step 4

Go to Intermittent Conditions

4
  1. Turn OFF the ignition.
  2. Disconnect the fuel rail pressure sensor connector.
  3. Connect a DMM between the 5-volt reference circuit and the low reference circuit of the fuel rail pressure sensor.
  4. Turn ON the ignition, with the engine OFF.

Is the DMM voltage more than the specified value?

4.6 V

Go to Step 5

Go to Step 6

5
  1. Turn OFF the ignition.
  2. Disconnect the fuel rail pressure sensor connector.
  3. Turn ON the ignition.
  4. Connect a 3-amp fused jumper wire between the 5-volt reference circuit and the signal circuit of the fuel rail pressure sensor.
  5. Turn OFF the ignition for 30 seconds.
  6. Turn ON the ignition, with the engine OFF.
  7. Observe the fuel rail pressure sensor parameter with a scan tool.

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
  1. Test the 5-volt reference circuit between the engine control module (ECM) and the fuel rial pressure sensor for the following conditions:
    2. • A short to ground circuit
    • A short to low reference circuit
  2. Repair the circuits, as necessary.

Did you find and correct the condition?

--

Go to Step 10

Go to Step 8

7
  1. Test the signal circuit between the ECM and the fuel rail pressure sensor for the following conditions:
    2. • A short to ground circuit
    • A short to low reference circuit
  2. Repair the circuits, as necessary.

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 Replacement/Restore Fuel Rate Data , and Fuel Injector Flow Rate Programming .

Did you complete the replacement?

--

Go to Step 10

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10
  1. Clear the DTCs with a scan tool.
  2. Turn OFF the ignition for 30 seconds.
  3. Start the engine.
  4. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records.

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?

--

Go to Diagnostic Trouble Code (DTC) List - Vehicle

System OK