GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2005 🢒 Chevy C Silverado - 2WD 🢒 Restraints 🢒 SIR 🢒 DTC P0193

Circuit Description

The engine control module (ECM) monitors the fuel rail pressure (FRP) via a FRP sensor. When the FRP is high, the signal voltage is high. When the FRP is low, the signal voltage is low. If the fuel rail pressure is above the upper limit for the sensor, DTC P0193 will set.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC P0193 Fuel Rail Pressure (FRP) Sensor Circuit High Voltage

Conditions for Running the DTC
    • DTC P0642 or P0643 is not set.
    • The ignition is ON.
    • The system is not in Powerdown mode.

Conditions for Setting the DTC

The ECM detects the signal circuit is more than 175 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.
    • The control module limits fuel injection and FRP.

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.

Step

Action

Values

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?

--

Go to Step 2

Go to Diagnostic System Check - Vehicle in Vehicle DTC Information

2

Are DTCs P0642 or P0643 set?

--

Go to DTC P0643 or DTC P0642

Go to Step 3

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

Is the Actual Fuel Rail Pressure within the specified range?

1-1.8 MPa

Go to Step 6

Go to Step 5

5
  1. Disconnect the fuel rail pressure (FRP) sensor connector.
  2. Probe the FRP 5-volt reference circuit with a DMM connected to a good ground. Refer to Troubleshooting with a Digital Multimeter in Wiring Systems.

Does the voltage measure near the specified value?

5 V

Go to Step 7

Go to Step 6

6
  1. Test the 5-volt reference circuit of the FRP sensor for high resistance or an open. Refer to Testing for Continuity , Testing for Short to Ground , Testing for a Short to Voltage in Wiring Systems.
  2. Repair as necessary. Refer to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 17

Go to Step 14

7
  1. Verify that the ignition is ON, with the engine OFF.
  2. Verify the FRP sensor harness connector is still disconnected.
  3. Measure the voltage between the FRP sensor signal circuit and a good ground circuit at the FRP harness connector with a DMM.

Is the current more than the specified value?

5 V

Go to Step 10

Go to Step 8

8
  1. Turn OFF the ignition.
  2. Disconnect the negative battery cables.
  3. Measure the resistance from the low reference circuit of the FRP sensor to a good ground.

Is the resistance less than the specified value?

5 ohms

Go to Step 9

Go to Step 12

9
  1. Turn OFF the ignition.
  2. Connect a 3-amp fused jumper wire between the signal circuit of the FRP sensor and the low reference circuit of the FRP sensor. Refer to Using Fused Jumper Wires in Wiring Systems.
  3. Turn ON the ignition, with the engine OFF.
  4. Observe the Actual FRP parameter with a scan tool.

Is the Actual FRP parameter at the specified value?

0 MPa

Go to Step 13

Go to Step 11

10

Test for a short to voltage in the FRP sensor signal circuit. Refer to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 17

Go to Step 16

11

Test the signal circuit of the FRP sensor for a high resistance or an open. Refer to Testing for Continuity and Wiring Repairs in Wiring Systems.

Did you Find and correct the condition?

--

Go to Step 17

Go to Step 14

12
  1. Disconnect the engine control module (ECM).
  2. Test the low reference circuit of the FRP sensor for a high resistance or an open. Refer to Testing for Continuity in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 17

Go to Step 14

13

Test for an intermittent and for a poor connection at the FRP sensor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 17

Go to Step 15

14

Test for an intermittent and for a poor connection at the ECM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 17

Go to Step 16

15

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

Did you complete the replacement?

--

Go to Step 17

--

16

Replace the ECM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming.

Did you complete the replacement?

--

Go to Step 17

--

17
  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 3

Go to Step 18

18

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