For 1990-2009 cars

# CHASSIS MANUAL REVISIONS AFFECTED PAGES LISTED

#### MODELS AFFECTED: 1986 RIVIERAS EQUIPPED WITH 3.8L SFI ENGINES (VIN CODE B)

Certain igniton system and driveability condition diagnostic procedures have been revised for 1986 Rivieras equipped with 3.8L SFI engines. The shaded areas of these procedures designate where changes were made.

Please update the following pages of your 1986 Buick Chassis Service Manual with this revised information:

1. Chart A-5 on Page 6E3-A-21. 2. The "EGR System Fault" information on Page 8D1-28 and Diagnostic Chart on Page 8D1-29. 3. Step 1 under Test Description on Page 8D1-30. 4. Mass Air Flow Sensor Code E033 Diagnostic Chart on Page 8D1-31. 5. Step 1 and 2 under Test Description on Page 8D1-32. 6. Mass Air Flow Sensor Code E034 Diagnostic Chart on Page 8D1-33. 7. The Cam Sensor Circuit Failure Diagnostic Chart on page 8D1-41. 8. The C3I EST or Bypass Circuit Failure Diagnostic Chart on page 8D1-43.

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.