ENGINE RUNS ROUGH OR HESITATES WHEN EXTERIOR LAMPS TURNED ON. Saturn Saturn 1991

For 1990-2009 cars

# ENGINE RUNS ROUGH OR HESITATES WHEN EXTERIOR LAMPS TURNED ON

#### SUBJECT: Engine Runs Rough or Hesitates when Exterior Lamps are Turned On, or When Brakes are Applied (Repair Fuel Pump Ground)

#### MODELS AFFECTED: 1991 and 1992 Saturns built before and including VIN NZ182094

CONDITION: Some customers may comment that the engine runs rough or hesitates when the exterior lamps are turned On, or when brakes are applied.

CAUSE: There may be an insufficient ground at rear body splice pack which is shared by fuel pump and rear lighting that causes the engine to run rough or hesitate when the exterior lamps are turned On, or when the brakes are applied. The insufficient ground may be caused by corrosion on weld stud for rear body ground splice pack.

#### NOTE: The rear lighting ground point was re - located to the package tray, near the left rear speaker, for vehicles produced after VIN NZ182094.

CORRECTION: Perform the following steps:

1. Turn Off all exterior lamps.

2. Apply parking brake.

3. Start vehicle and let engine idle.

4. Turn On exterior lamps.

o If engine runs rough, refer to "Procedure" in this bulletin.

o If engine does not run rough, refer to the next step.

5. Apply service brakes.

o If engine runs rough, refer to "Procedure" in this bulletin.

o If engine does not run rough, refer to the next step.

6. Check for voltage as follows:

a. Locate rear body ground splice pack, under carpet in rear compartment, near left taillamp assembly.

b. Install a diagnostic service probe (P/N 217673) on the wire from pin G at the rear body ground splice pack.

#### IMPORTANT: The engine and exterior lamps must remain On for the following step.

c. Using a voltmeter on a scale which displays tenths of a volt, measure the voltage from the diagnostic service probe to chassis ground. (Deck lid striker where ELPO coating is worn off, or negative battery bolt can be used for a good chassis ground reference point.)

o If voltage is greater than 0.5 volt, repair rear body splice pack ground using procedures in this bulletin.

o If voltage is less than or equal to 0.5 volt, refer to appropriate Saturn Service Manual for diagnostic procedures.

PROCEDURE

1. Turn ignition and exterior lamps Off and make sure service brakes are not applied.

2. Locate rear body splice pack ground weld stud at body ground point "T"

3. Remove nut, washer and ring terminal from weld stud.

4. Using a wire brush, clean all corrosion from weld stud.

5. Cut wire from rear body splice pack, 51 mm (2 in.) from ring terminal and discard ring terminal.

6. Strip end of wire 9.5 mm (3/8 in.) and visually inspect wire strands for corrosion. If corrosion is present, cut wire back further and re - strip as necessary until clean, non - corroded wire strands are obtained. Care must be used to revent cutting of wire strands.

7. Position stripped ends of wire from wiring harness and from new ring terminal (P/N 12112247) into blue colored connector-crimp and seal (P/N 12089190), included with ring terminal.

8. Hand crimp using the approved crimping tool. Gently tug on wires to make sure they are secure before applying heat.

9. Apply heat using butane torch (included with special tool SA9138Z), heating to 175 degrees Celsius ( 347 degrees Fahrenheit), working from the center to the ends, until glue flows around both edges of crimp and seal sleeve.

#### CAUTION:

DO NOT USE MATCH OR OPEN FLAME TO APPLY HEAT TO SEAL.

10. Install new ring terminal over weld stud and secure with new washer (P/N 11503969) and nut (P/N 11515530).

Torque: 10 N-m (89 in-lbs)

11. Repeat voltage measurements from step 6c of "Corrections" in this bulletin. If voltage is equal to or above 0.5 volt, inspect rear body ground splice pack for terminal tightness and repair as necessary.

12. Apply Lubriplate lubricant (or equivalent), over weld stud, ring terminal, washer and nut generously to protect ground attachment from corrosion.

13. Verify that the concern has been repaired.

PARTS REQUIREMENTS: 12112247 Lead Kit-Ring Terminal

12089190 Connector-Crimp and Seal (included with Lead Kit - Ring Terminal)

11515530 Nut-Body Wiring Harness Ground

11503969 Washer-Body Wiring Harness Ground

217673 Diagnostic Service Probe (Available from OTC Division of SPX Corporation at 1 800 533-5338, or from Packard Electric at 1 800 - PACKARD with a minimum total order of $25.00 for any combination of parts.)

CLAIM INFORMATION: To receive credit for this repair, submit a claim through the Saturn Dealer System as follows:

Labor Case Operation Type Description Code Time -------------------------------------------------------- VW Wiring and/or Connector N6478 0.5 hrs Repair-Splice Packs, Grounds

General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.