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Fuel Transfer Pump Inoperative (Replace Fuel Transfer Module)

Subject:Fuel Transfer Pump Inoperative (Replace Fuel Transfer Module)

Models:1990-2001 Chevrolet and GMC 6-7H C-Series Conventional Medium Duty Models
With Gas Engine (VINs E, D, B, M, P -- RPOs L18, LP4, L21, LRO, LSO)
1997-2001 Chevrolet and GMC 6-7F T-Series Medium Duty Tilt Cab Models
With Isuzu Diesel Engine (VIN 3 -- RPO LG4) or Caterpillar® Diesel Engine (VIN C -- RPO LG5)
1996-2001 Chevrolet and GMC C/K 3500 (1 Ton) Models
With Gas Engine (VINs G, J, R -- RPOs L18, L29, L31) or Diesel Engine (VIN F -- RPO L65)
and Dual Fuel Tanks



This bulletin is being revised to update part usage for C/K 3500 Models in the Parts information. Please discard Corporate Bulletin Number  01-06-04-037A (Section 06 -- Engine/Propulsion System).


Condition

Some customers may comment on inoperative secondary fuel tank transfer pumps. In some instances, customers may experience multiple failures of the service replacement pumps.

Cause

This condition may be caused by the "Four Minute Final Pump Out" feature of the fuel level control module. This feature can command the transfer pump to on when there is no fuel in the secondary tank.

This command occurs with every ignition cycle for a period of four minutes. These transfer pumps can overheat and become inoperative when they are run dry.

Customers that never add fuel to the secondary tank can further compound this issue. In these cases, the secondary pump would become inoperative in a very short period of time.

Correction

Three new transfer pump modules have been released to correct this condition. The new module curtails the "Four Minute Final Pump Out" feature. When the sender in the secondary tank drops to a resistance reading of 2 ohms, the pump-out feature is disabled. At resistance readings greater than 2 ohms, the pump-out feature will continue to function. However, under this condition there should be enough fuel in the tank to prevent pump failure. Replace the fuel transfer module using the procedures and part numbers listed below.

C-Series Conventional Cab


    Object Number: 206464  Size: SH
  1. Remove the component box lid.

  2. Object Number: 744073  Size: SH
  3. Disconnect the fuel transfer module electrical connector (2).

  4. Object Number: 744077  Size: SH
  5. Remove the fuel transfer module mounting nuts and the washers.
  6. Remove the fuel transfer module.
  7. Install the fuel transfer module, the washers, and the nuts.
  8. Connect the fuel transfer module electrical connector.
  9. Install the component box lid.
  10. Tighten
    Tighten the bolts to 30 N·m (22 lb ft).

T-Series Tilt Cab


    Object Number: 601878  Size: MH
  1. Disconnect the fuel transfer module electrical connector.
  2. Remove the fuel transfer module mounting bolts.
  3. Remove the fuel transfer module (1).
  4. Install the fuel transfer module and the bolts.
  5. Connect the fuel transfer module electrical connector.

CK 3500

  1. Disconnect the fuel transfer module electrical connector.

  2. Object Number: 801461  Size: SH
  3. Remove the fuel transfer module mounting bolts (1).
  4. Remove the fuel transfer module (2).
  5. Install the fuel transfer module and the bolts.
  6. Connect the fuel transfer module electrical connector.

Parts Information

P/N

Description

Usage

15061009

Module, Fuel Transfer

C6-7 Conventional Models with Gas Engine

F6-7 Tilt Cab Models with Diesel Engine

15061010

Module, Fuel Transfer

1998-2001 C/K 3500 with Gas Engine

15061011

Module, Fuel Transfer

1996-1997 C/K 3500 with Gas Engine

1996-2001 C/K 3500 with Diesel Engine

Parts are currently available from GMSPO.

Warranty Information

For vehicles repaired under warranty, use:

Labor Operation

Description

Labor Time

L0764

(C-Series)

Module, Fuel Sender and Balance Pump Control - Replace

0.3 hr*

L0764

(T-Series)

Module, Fuel Sender and Balance Pump Control - Replace

0.2 hr*

L0764

(CK 3500)

Module, Fuel Sender and Balance Pump Control - Replace

0.2 hr*

*This time is updated from the current Labor Time Guide. The next update of the Labor Time Guide will contain this change.