GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2003 🢒 GMC C Sierra - 2WD (CNG) 🢒 Engine 🢒 Engine Controls - 6.0L 🢒 DTC P0192

Circuit Description

The fuel rail pressure (FRP) sensor is a pressure sensor. The powertrain control module (PCM) supplies about 5 volts on the FRP sensor reference voltage circuit. The PCM 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 PCM uses the FRP sensor information in order to adjust fuel trim.

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

Conditions for Running the DTC
    • The engine speed is more than 100 RPM.
    • DTC P0191 is not set.

Conditions for Setting the DTC
    • The FRP sensor signal voltage is less than 0.1 volts.
    • The condition exists for at least 2.5 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.

  1. This step determines if the condition is present.

    2.

  2. This step determines if the FRP sensor is the cause of the condition.

    3.

  3. This step determines if the 5-volt reference circuit is the cause of the condition.

Step

Action

Value(s)

Yes

No

Schematic Reference: Engine Controls Schematics

Connector End View Reference: Engine Controls Connector End Views

1

Did you perform the Diagnostic System Check Alternative Fuels - Engine Controls?

--

Go to Step 2

Go to Diagnostic System Check - Alternative Fuels (Engine Controls)

2

  1. Turn ON the ignition, with the engine OFF.
  2. Observe the Fuel Rail Pressure (FRP) data display with a scan tool.

Does the scan tool display the FRP sensor voltage less than the specified value?

0.1 V

Go to Step 4

Go to Step 3

3
  1. Observe the Freeze Frame and/or the Failure records data for this DTC.
  2. Turn the ignition OFF 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 and/or the Failure records data.

Does the DTC fail this ignition cycle?

--

Go to Step 4

Go to Intermittent Conditions

4

  1. Disconnect the FRP sensor. Refer to Fuel Injection Fuel Rail Fuel Pressure Sensor Replacement .
  2. Connect a 3-amp fused jumper between the signal circuit and the 5-volt reference circuit of the FRP sensor.
  3. Observe the FRP sensor data display with a scan tool.

Does the scan tool display the FRP sensor voltage more than the specified value?

4.95 V

Go to Step 8

Go to Step 5

5

  1. Remove the fused jumper.
  2. Measure the voltage from the 5-volt reference circuit of the FRP sensor with a DMM.

Is the voltage less than the specified value?

4.95 V

Go to Step 6

Go to Step 7

6

Test the FRP sensor signal circuit for a short to ground or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems in the C/K Pickup Service Manual.

Did you find and correct the condition?

--

Go to Step 12

Go to Step 9

7

Test for an open or a short to ground on the 5 Volt reference circuit of the FRP sensor. Refer to Circuit Testing and Wiring Repairs in Wiring Systems in the C/K Pickup Service Manual.

Did you find and correct the condition?

--

Go to Step 12

Go to Step 9

8

Inspect for proper terminal contact at the harness connector of the FRP sensor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems in the C/K Pickup Service Manual.

Did you find and correct the condition?

--

Go to Step 12

Go to Step 10

9

Inspect for proper terminal contact at the harness connector of the PCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems in the C/K Pickup Service Manual.

Did you find and correct the condition?

--

Go to Step 12

Go to Step 11

10

Replace the fuel rail pressure sensor. Refer to Fuel Injection Fuel Rail Fuel Pressure Sensor Replacement .

Did you complete the replacement?

--

Go to Step 12

--

11

Replace the PCM. Refer to Powertrain Control Module Replacement in the C/K Pickup Service Manual.

Did you complete the replacement?

--

Go to Step 12

--

12
  1. Observe the Freeze Frame/Failure Records for this DTC.
  2. Turn OFF the ignition for 30  seconds.
  3. Turn ON the ignition, with the engine OFF.
  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 13

13

Observe the Capture Info with a scan tool.

Are there any DTCs that have not been diagnosed?

--

Go to Diagnostic Trouble Code (DTC) List

System OK