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Makes 🢒 GMC_Truck 🢒 2001 🢒 GMC C Sierra - 2WD 🢒 Bulletins 🢒 SMU - Revised DTC P0088 Table

SMU - Revised DTC P0088 Table

Subject:Revised DTC P0088 Table

Models:2001 Chevrolet and GMC C/K Pickup Models (Silverado, Sierra)
with 6.6L Engine (VIN 1 -- RPO LB7)


This bulletin is being issued to revise the DTC P0088 table in the Engine Controls-6.6L sub-section of the Service Manual. Please replace the current information in the Service Manual with the following information.

The following information has been updated within SI. If you are using a paper version of this Service Manual, please make a reference to this bulletin on the affected page.

Test Description

The numbers below refer to the step numbers on the diagnostic table.

  1. DTC P0090 is a current flow problem in the FRP regulator circuit. This incorrect current draw could lead to incorrect fuel pressure. This hardware problem should be diagnosed before the performance DTC is checked.

DTC P0088

Step

Action

Values

Yes

No

Schematic Reference: Engine Controls Schematics

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 parameter within the specified range?

1.2-1.4 MPa

Go to Step 3

Go to Step 6

3

Did DTC P0090 also set?

--

Go to DTC P0090

Go to Step 4

4
  1. Start the engine.
  2. Observe the Actual Fuel Rail Pressure on the scan tool.
  3. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text or as close to the Freeze Frame/Failure Records data that you observed.

Is the Actual Fuel Rail Pressure more than the specified value?

167 MPa

Go to Step 10

Go to Step 5

5
  1. Start and idle the engine.
  2. Perform the following test at idle and at 2000 RPM:
    3. • Change the fuel pressure with a scan tool, incrementing through the entire fuel pressure range.
    • Observe the actual vs desired fuel pressures at each fuel pressure level.

Does the fuel pressure increment and stabilize through the entire fuel pressure range, with actual and desired fuel pressure within 2 MPa of each other at every fuel pressure?

--

Go to Diagnostic Aids

Go to Step 10

6
  1. Disconnect the fuel rail pressure sensor.
  2. Observe the Actual Fuel Rail Pressure parameter with a scan tool.

Does the Actual Fuel Rail Pressure measure more than the specified value?

175 MPa

Go to Step 9

Go to Step 7

7

Test the fuel rail pressure sensor signal circuit for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 11

Go to Step 8

8

Replace the engine control module. Refer to Engine Control Module (ECM) Replacement.

Did you complete the replacement?

--

Go to Step 11

--

9

Replace the fuel rail pressure sensor. Refer to Fuel Rail Pressure (FRP) Sensor Replacement.

Did you complete the replacement?

--

Go to Step 11

--

10

Replace the FRP regulator. Refer to Fuel Pressure Regulator Replacement.

Did you complete the replacement?

--

Go to Step 11

--

11
  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 .

Does the DTC fail this ignition?

--

Go to Step 2

Go to Step 12

12

With a scan tool, observe the stored information, Capture Info.

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

--

Go to Diagnostic Trouble Code (DTC) List

System OK