GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2006 🢒 TopKick C-Series (Conventional) C6/C7/C8 🢒 Restraints 🢒 SIR 🢒 DTC P2923

Circuit Description

The fuel supply pump draws fuel from the fuel tank and pumps the high pressure fuel to the fuel rail. The quantity of the fuel discharged from the supply pump controls the pressure in the fuel rail. The suction control valve (SCV) in the fuel supply pump effects this control in accordance with the command received from the engine control module (ECM). The fuel pressure of the high pressure side is measured by the fuel rail pressure sensor. The ECM calculates the fuel feed quantity based on the fuel pressure sensor signal and other many signals. If the ECM detects an excessively large deviation of the fuel feed quantity, this DTC will set.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC P2923 Fuel Supply Pump Malfunction

Conditions for Running the DTC
    • The ignition is ON.
    • The deviation of the rail pressure is less than 2 MPa (290 psi).
    • The crankshaft position (CKP) sensor is normal.
    • The fuel rail pressure sensor is normal.
    • The deviation of the fuel quantity is less than 2 mm³ per stroke.
    • The engine speed is more than 500 RPM.

Conditions for Setting the DTC

The deviation of the fuel feed quantity is more than the threshold.

Action Taken When the DTC Sets
    • The ECM illuminates the malfunction indicator lamp (MIL) and Reduced Engine Power indicator lamp, if fitted, when the diagnostic runs and fails.
    • The ECM records the operating conditions at the time the diagnostic fails. The ECM stores this information in the Failure Records.
    • The ECM limits fuel rail pressure for fail-safe operation.
    • The ECM closes the exhaust gas recirculation (EGR) valve and holds to close position.

Conditions for Clearing the DTC
    • A current DTC clears when the ignition is turned OFF.
    • Clear the MIL and the DTC with a scan tool.

Step

Action

Yes

No

Schematic Reference: Engine Controls Schematics

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle in Vehicle DTC Information

2
  1. Install a scan tool.
  2. Start the engine.
  3. Monitor the DTC information with a scan tool.

Is DTC P0091, P0092, P0192, P0193, P0201-P0206, P2163-P2166, P2011, or P2012 also set?

Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC Information

Go to Step 3

3
  1. Perform the fuel system check. Refer to Fuel System Diagnosis .
  2. If a condition is found, repair as necessary.

Did you find and correct the condition?

Go to Step 8

Go to Step 4

4
  1. Observe the 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 5

Go to Step 8

5

Replace the supply pump. Refer to Fuel Injection Pump Replacement .

Did you complete the replacement?

Go to Step 6

--

6
  1. Bleed the air from the fuel system.
  2. Clear the DTCs with a scan tool.
  3. Turn OFF the ignition for 30 seconds.
  4. Start the engine.
  5. 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 7

Go to Step 8

7

Important: The new engine control module (ECM) must be programmed.

Replace the ECM. Refer to Engine Control Module Programming and Setup in Programming and Setup, Engine Control Module Replacement/Restore Fuel Rate Data , and Fuel Injector Flow Rate Programming .

Did you complete the replacement?

Go to Step 8

--

8
  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 9

9

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