GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The engine control module (ECM) monitors the fuel rail pressure (FRP) via a FRP sensor. When the fuel rail pressure is high the signal voltage is high. When the FRP is low the signal voltage is low. If the FRP is not above the lower limit for the sensor, DTC P0192 will set.

DTC Descriptor

This diagnostic supports the following DTC:

DTC P0192 Fuel Rail Pressure (FRP) Sensor Circuit Low Voltage

Conditions for Running the DTC

    • DTCs P0642 or P0643 are not set.
    • The ignition is ON.

Conditions for Setting the DTC

The ECM detects the signal circuit is less than 1.2 MPa.

Action Taken When the DTC Sets

    • The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.
    • 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.

  1. This step tests for the proper operation of the circuit in the low voltage range.

  2. This step tests for the proper operation of the circuit in the high voltage range. If the fuse in the jumper opens when you perform this test, the signal circuit is shorted to ground.

Step

Action

Value(s)

Yes

No

Schematic Reference: Engine Controls Schematics

Connector End View Reference: Engine Control Module Connector End Views or Engine Controls Connector End Views

1

Did you perform the Diagnostic System Check - Vehicle?

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Go to Step 2

Go to Diagnostic System Check - Vehicle in Vehicle DTC Information

2

  1. Install a scan tool.
  2. Turn ON the ignition, with the engine OFF.
  3. Observe the Actual Fuel Rail Pressure parameter with a scan tool.

Is the Actual Fuel Rail Pressure parameter within the specified range?

1.2-1.9 MPa

Go to Intermittent Conditions in Wiring Systems

Go to Step 3

3

  1. Turn OFF the ignition.
  2. Disconnect the fuel rail pressure (FRP) sensor.
  3. Turn ON the ignition, with the engine OFF.
  4. Observe the Actual Fuel Rail Pressure parameter with a scan tool.

Is the Actual Fuel Rail Pressure parameter less than the specified value?

175 MPa

Go to Step 4

Go to Step 5

4

Test the signal circuit of the FRP sensor for a short to ground or high resistance. Refer to Testing for Short to Ground and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 7

Go to Step 6

5

Replace the FRP sensor. Refer to Fuel Injection Fuel Rail Fuel Pressure Sensor Replacement .

Did you complete the replacement?

--

Go to Step 7

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6

Replace the engine control module (ECM). Refer to Engine Control Module Replacement .

Did you complete the replacement?

--

Go to Step 7

--

7

  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 8

8

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 in Vehicle DTC Information

System OK