GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2003 🢒 GMC K Sierra - 4WD 🢒 Engine 🢒 Engine Controls - 6.6L 🢒 DTC P0193

Circuit Description

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

Conditions for Running the DTC
    • DTC P0641 or P0651 are 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/FailureRecords.
    • The control module limits fuel injection and fuel rail pressure.

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-Engine Controls?

--

Go to Step 2

Go to Diagnostic System Check - Engine Controls

2
  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?

1.2-1.9 MPa

Go to Step 4

Go to Step 3

3
  1. Disconnect the 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 5

Go to Step 4

4
  1. Test the 5-volt reference circuit of the FRP sensor for a short to voltage, 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 15

Go to Step 12

5
  1. Verify that the ignition is ON, with the engine OFF.
  2. Verify the FRP sensor harness connector is still disconnected.
  3. Measure the current between the FRP sensor signal circuit and ground circuit at the FRP harness connector with a DMM.

Is the current more than the specified value?

10 mA

Go to Step 8

Go to Step 6

6
  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 7

Go to Step 10

7
  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?

0.0 MPa

Go to Step 11

Go to Step 9

8

Test for a short to voltage, 12-volt reference, or 5-volt reference on the FRP sensor signal circuit. Refer to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 15

Go to Step 14

9

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 15

Go to Step 12

10
  1. Disconnect the 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 15

Go to Step 12

11

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 15

Go to Step 13

12

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 15

Go to Step 14

13

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

Did you complete the replacement?

--

Go to Step 15

--

14

Replace the ECM. Refer to Engine Control Module Replacement .

Did you complete the replacement?

--

Go to Step 15

--

15
  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 16

16

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