GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2002 🢒 GMC K Sierra - 4WD (CNG) 🢒 DTC 🢒 DTC P0192

Circuit Description

The fuel rail pressure (FRP) sensor is a pressure sensor. The alternative fuels engine control module (ECM) supplies about 5 volts on the FRP sensor reference voltage circuit. The alternative fuels ECM also supplies a ground 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 MAP signal voltage increases. The alternative fuels ECM monitors the FRP signal circuit voltage in order to determine the correct fuel injector pulse width modulation.

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 greater than 100 RPM.
    • alternative fuels ECM DTC P0336 is not set.

Conditions for Setting the DTC

The alternative fuels ECM monitors a FRP sensor signal voltage of less than 0.05 volts for at least 10 seconds continuously.

Action Taken When the DTC Sets

    • A first failure of this DTC will NOT illuminate the MIL and will store as Last Test Failed but not as History.
    • The Alternative Fuels ECM will illuminate the MIL and store the DTC as History after 2 consecutive drive trips that the diagnostic runs and fails.
    • The Alternative Fuels ECM will record operating conditions at the time the DTC sets. This information will be stored as Freeze Frame data.

Conditions for Clearing the MIL/DTC

    • The Last Test Failed status will clear when the DTC runs and passes.
    • The Alternative Fuels ECM will turn OFF the MIL after 3 consecutive drive trips that the DTC runs and passes.
    • The History status will clear after 40 consecutive WARM-UP cycles with NO failures of ANY DTC.
    • All DTC Information can be cleared 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 signal circuit of 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

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. With a scan tool establish communication with the alternative fuels ECM.
  3. Observe the Fuel Rail Pressure (FRP) data display.

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

0.5 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.
  5. Monitor the alternative fuels ECM DTC information with a scan tool.

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. 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 5

Go to Step 6

5

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 7

Go to Step 8

6

Test for a short to ground on the signal 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

7

Test for an open or a short to ground on the 5 Volt reference circuit of the FRP sensor. Disconnect the fuel tank pressure (FTP) sensor in order to determine if the FTP sensor is the cause of a short. 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 alternative fuels ECM. 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 .

Is the replacement complete?

--

Go to Step 12

--

11

Replace the alternative fuels ECM. Refer to Alternative Fuels Engine Control Module Replacement .

Is the replacement complete?

--

Go to Step 12

--

12
  1. Use the scan tool in order to clear the DTCs from the following control modules:
    2. • alternative fuels ECM
    • PCM
  2. Turn OFF the ignition for 30 seconds.
  3. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.

Does the DTC run and pass?

--

Go to Step 13

Go to Step 2

13

With a scan tool, select Capture Info in order to observe the stored information.

Does the scan tool display any DTCs that you have not diagnosed?

--

Go to Diagnostic Trouble Code (DTC) List

System OK