GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2001 🢒 GMC T-Series Medium Duty Truck F6/F7/F8 🢒 DTC 🢒 DTC 0261

Circuit Description

The flow damper comprises a piston, ball, spring seat, and spring. The flow damper is used to damp the pressure pulsating in the common rail and the injection pipe. During driving, the flow of fuel makes the piston, ball, and spring seat move a little to the injector side and float. If too much fuel passes the flow damper, the ball moves further toward the injector until the ball comes into contact with the seat surface of the flow damper unit, thereby shutting the fuel passages.

Conditions for Running the DTC
    • DTCs 0271, 0158, or 0159 are not set.
    • The water temperature is higher than 60°C (140°F).

Conditions for Setting the DTC

Correction of uneven injection amount exceeding 4 mm³/second and this continues for 20 cycles.

Action Taken When the DTC Sets
    • The engine control module (ECM) will illuminate the malfunction indicator lamp (MIL) the first time the fault is detected.
    • Judgement cylinder injection stops

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.

DTC 0261 can be cleared by using the Clear Info option on the Tech 2 or by using the Diag Clear Switch.

Diagnostic Aids

Inspect for the following conditions:

    • Poor connections at the ECM
        Inspect the harness connectors for backed-out terminals, improper mating, broken locks, improperly formed or damaged terminals, and poor terminal-to-wire connections.
    • Inspect the fuel filter for a restriction.

Step

Action

Yes

No

Schematic Reference: Engine Controls Schematics

1

Is DTC 0261 set with the ignition ON or with the engine operating?

Go to Step 2

Go to Diagnostic Aids

2
  1. Start the engine.
  2. Idle the engine until the engine reaches 60°C (140°F) or more.
  3. Turn the engine OFF.
  4. Start the engine and let the engine idle.

Are any DTCs displayed?

Go to Step 4

Go to Step 3

3
  1. Inspect for clutch chatter, a malfunctioning neutral switch, or clutch switch under a no load condition.
  2. Repair the condition as necessary.

Did you complete the repair?

Go to Step 9

--

4

Remove the flow damper from the common rail according to diagnostic code.

Does the flow damper remain open?

Go to Step 7

Go to Step 5

5
  1. Inspect the injection pipe for being loose or broken.
  2. Repair or replace the injection pipe as necessary.

Did you complete the action?

Go to Step 9

Go to Step 6

6
  1. Inspect the injector assembly for poor operation.
  2. Repair or replace the injector assembly as necessary. Refer to Fuel Injector Replacement .

Did you complete the action?

Go to Step 9

Go to Step 8

7

Replace the flow damper.

Did you complete the replacement?

Go to Step 8

--

8

Do you have a similar problem as in Step 3?

Go to Step 3

Go to Step 9

9

Start the engine.

Are any DTCs displayed?

Go to Step 2

System OK