VEHICLE SPEED SURGE OR SLOW RESPONSE WITH CRUISE CONTROL

SUBJECT: VEHICLE SPEED SURGE OR SLOW RESPONSE WITH CRUISE CONTROL ENGAGED (REPLACE SPEEDOMETER DRIVE AND DRIVEN GEAR, AND CRUISE CONTROL MODULE)

MODELS: 1993-95 CHEVROLET CAMARO 1993-95 PONTIAC FIREBIRD WITH 3.4L V6 ENGINE (VIN S - RPO L32)

CONDITION:

YOU MAY RECEIVE COMMENTS CONCERNING THE CRUISE CONTROL SYSTEM. THESE COMMENTS MAY INVOLVE ONE OF THREE CONDITIONS:

CONDITION I

APPLIES ONLY TO 1993 AND 1994 VEHICLES WITH 5SP MANUAL TRANSMISSION. DRIVERS MAY EXPERIENCE A MODERATE TO RAPID VEHICLE SPEED SURGING OF +/- ONE (1) MILE PER HOUR (MPH) OR MORE WHILE THE CRUISE CONTROL SYSTEM IS ENGAGED. THIS CONDITION USUALLY OCCURS WHEN THE CRUISE CONTROL SYSTEM IS SET BETWEEN 50 AND 60 MPH AND ON LEVEL ROADS. BUT THE SURGING MAY ALSO OCCUR AT OTHER SET SPEEDS. THIS SPEED FLUCTUATION MAY OR MAY NOT BE NOTICEABLE ON THE SPEEDOMETER.

CONDITION II

APPLIES ONLY TO 1993 AND 1994 VEHICLES WITH AUTOMATIC TRANSMISSION. DRIVERS MAY EXPERIENCE A MODERATE TO RAPID VEHICLE SPEED SURGING OF +/- ONE (1) MILE PER HOUR (MPH) OR MORE WHILE THE CRUISE CONTROL SYSTEM IS ENGAGED. THIS CONDITION USUALLY OCCURS WHEN THE CRUISE CONTROL SYSTEM IS SET ABOVE 65 MPH AND ON LEVEL ROADS. BUT THE SURGING MAY ALSO OCCUR AT OTHER SET SPEEDS. THIS SPEED FLUCTUATION MAY OR MAY NOT BE NOTICEABLE ON THE SPEEDOMETER.

CONDITION III

APPLIES ONLY TO 1995 V6 ENGINE EQUIPPED VEHICLES REGARDLESS OF TRANSMISSION TYPE. DRIVERS MAY EXPERIENCE SLOW RESPONSE FROM THE CRUISE CONTROL SYSTEM IN MAINTAINING SET SPEED, PARTICULARLY ON HILLY OR NON-LEVEL ROADS. UNLIKE "CONDITION I" OR "CONDITION II", THIS IS NOT A MODERATE TO RAPID CYCLING OR SURGING OF VEHICLE SPEED ABOVE OR BELOW THE SET SPEED, BUT RATHER, IT IS A SLOW FALLING OFF OR OVERSHOOT OF THE SET SPEED.

IMPORTANT: THE CORRECT IDENTIFICATION OF THE ABOVE CONDITIONS WILL GREATLY AFFECT THE QUALITY OF THE REPAIRS. IN CERTAIN INSTANCES, AN IMPROPER DIAGNOSIS OF THE CONDITION WILL NOT ONLY LEAD TO AN IMPROPER REPAIR BUT MAY WORSEN THE ORIGINAL CONCERN.

CAUSE:

CONDITION I

APPLIES ONLY TO 1993 OR 1994 5-SPEED MANUAL TRANSMISSION VEHICLES. A MISALIGNED VEHICLE SPEED SENSOR (VSS) DRIVE GEAR IN THE MANUAL TRANSMISSION MAY BE THE CAUSE OF THE VEHICLE SPEED SURGE. THIS MISALIGNMENT RESULTS IN AN INCONSISTENT SIGNAL BEING SENT TO THE POWERTRAIN CONTROL MODULE (PCM). IN ADDITION, THE CRUISE CONTROL MODULE MAY BE TOO SENSITIVE OR TOO RESPONSIVE AND COMPENSATES TOO RAPIDLY TO THAT INCONSISTENT SIGNAL.

CONDITION II

APPLIES ONLY TO 1993 AND 1994 VEHICLES WITH AUTOMATIC TRANSMISSION. AN ERRATIC SPEED SIGNAL AT HIGHER SPEEDS MAY BE THE CAUSE OF THE VEHICLE SPEED SURGE.

IMPORTANT: AN AUTOMATIC TRANSMISSION DOES NOT USE SPEEDOMETER DRIVE OR DRIVEN GEARS. THE CRUISE CONTROL MODULE MAY BE TOO SENSITIVE OR TOO RESPONSIVE TO THE PROCESSED SPEED SIGNAL IT RECEIVES AND TRIES TO COMPENSATE TOO RAPIDLY.

CONDITION III

APPLIES TO ONLY 1995 V6 ENGINE EQUIPPED VEHICLES REGARDLESS OF TRANSMISSION TYPE. THE REDUCED GAIN CRUISE CONTROL MODULE USED TO ADDRESS "CONDITION I" AND "CONDITION II" MAY BE THE CAUSE OF THE SLOW RESPONSE FROM THE CRUISE CONTROL SYSTEM IN MAINTAINING SET SPEED.

CORRECTION:

CONDITION I

A REVISED VEHICLE SPEED SENSOR (VSS) DRIVE AND DRIVEN GEAR IS AVAILABLE TO ADDRESS THE CONDITION. THE NEW GEAR SET HAS A REVISED TOOTH PROFILE TO PROVIDE A MORE UNIFORM VEHICLE SPEED SIGNAL. IN ADDITION, AN INSTALLATION TOOL IS ALSO REQUIRED FOR PROPER DRIVE GEAR ALIGNMENT DURING INSTALLATION. A REVISED CRUISE CONTROL MODULE WITH A LOWER GAIN IS ALSO AVAILABLE. THIS NEW MODULE IS LESS SENSITIVE OR RESPONSIVE TO THE VEHICLE SPEED SIGNAL GENERATED BY THE MIS-ALIGNED GEARS.

FOLLOW THE REPAIR PROCEDURE INDICATED BELOW.

NOTICE: BEFORE VEHICLE IS TO BE SERVICED, MODIFY A FRONT YOKE ASSEMBLY (PART NUMBER 7849818), PER FIGURE TO BE USED AS AN INSTALLATION TOOL. THIS TOOL WILL BE REUSABLE AND THEREFORE NO MORE THAN ONE WILL BE PERMITTED PER DEALERSHIP.

THE CLOSE FIT OF THE MODIFIED YOKE (VERSUS THE CURRENTLY AVAILABLE TOOL) TO THE TRANSMISSION OUTPUT SHAFT WILL INSURE THE SPEEDOMETER GEAR WILL BE INSTALLED SQUARELY TO THE OUTPUT SHAFT. THIS IS CRITICAL.

REMOVE

1. TRANSMISSION ASSEMBLY FROM VEHICLE.

IMPORTANT: REMOVAL OF TRANSMISSION SHIFT LEVER (80) AND BOLTS FROM EXTENSION HOUSING (90) WHEN TRANSMISSION ASSEMBLY IS PARTIALLY REMOVED FROM VEHICLE, WILL PROVIDE ADDITIONAL CLEARANCE FOR THE FINAL REMOVAL OF TRANSMISSION ASSEMBLY FROM THE VEHICLE.

2. VEHICLE SPEED SENSOR (VSS) RETAINER BOLT FROM EXTENSION HOUSING (90).

3. VEHICLE SPEED SENSOR FROM EXTENSION HOUSING (90).

4. DISCARD SPEEDOMETER DRIVEN GEAR FROM VEHICLE SPEED SENSOR.

5. TRANSMISSION SHIFT LEVER (80) AND BOLTS IF NOT REMOVED ALREADY. SEE ABOVE.

6. PLACE OFFSET LEVER (82) IN NEUTRAL POSITION (CENTERED).

NOTICE: REMOVAL OF OFFSET LEVER (82) IN POSITION OTHER THAN NEUTRAL (CENTERED) MAY RESULT IN DRIVING THE ROLL PIN (83) INTO THE DETENT PLATE WITHOUT RELEASING LEVER, MAKING FURTHER DISASSEMBLY EXTREMELY DIFFICULT.

7. ROLL PIN (83) FROM OFFSET LEVER (82).

8. EXTENSION HOUSING BOLTS (91) FROM TRANSMISSION CASE (67).

9. EXTENSION HOUSING (90) AND OFFSET LEVER (82) AS AN ASSEMBLY FROM THE TRANSMISSION CASE (67).

10. DETENT BALL (85) AND SPRING (84) FROM OFFSET LEVER (82).

11. SNAP RING (26) FROM OUTPUT SHAFT (14).

12. DISCARD RUBBER "DONUT" (NOT NUMBERED OR SHOWN) FROM OUTPUT SHAFT (14).

13. DISCARD ORIGINAL SPEEDOMETER DRIVE GEAR (27) FROM OUTPUT SHAFT (14).

14. DISCARD RETAINING CLIP, SPEEDOMETER DRIVE GEAR (28).

INSTALL

1. POSITION NEW RETAINING CLIP (28) ONTO OUTPUT SHAFT (14).

2. REVISED SPEEDOMETER DRIVE GEAR (27) ONTO OUTPUT SHAFT USING MODIFIED FRONT YOKE.

IMPORTANT: THE MODIFIED FRONT YOKE MUST BE USED TO INSURE THE SQUARENESS OF THE SPEEDOMETER DRIVE GEAR (27) TO THE OUTPUT SHAFT (14).

- USING MODIFIED FRONT YOKE, PUSH REVISED SPEEDOMETER DRIVE GEAR (27) ONTO OUTPUT SHAFT (14) WITH YOKE'S MODIFIED NOTCH LINED UP WITH THE RETAINING CLIP (28).

- SLIDE SPEEDOMETER DRIVE GEAR (27), USING YOKE, ONTO RETAINING CLIP (28) UNTIL GEAR IS POSITIONED BETWEEN THE TABS OF THE CLIP.

NOTICE: SLIDE GEAR (27) ONLY FAR ENOUGH TO POSITION IT BETWEEN THE TABS OF THE RETAINING CLIP (28). DO NOT OVERTRAVEL, AS THIS MAY TILT THE GEAR.

TO INSURE THE SQUARENESS OF INSTALLATION, THE YOKE MUST NOT CONTACT THE RETAINING CLIP (28) WHILE THE SPEEDOMETER DRIVE GEAR (27) IS BEING INSTALLED. THE MODIFIED NOTCH IN THE YOKE PROVIDES THE NECESSARY CLEARANCE.

3. SNAP RING (26) ONTO THE OUTPUT SHAFT (14).

4. APPLY A 3 MM (1/8 INCH) BEAD OF RTV SEALANT, GM PART NUMBER 12345739 TO TRANSMISSION CASE (67).

5. DETENT BALL (85) AND SPRING (84) INTO OFFSET LEVER (82).

6. EXTENSION HOUSING (90) AND OFFSET LEVER (82) AS AN ASSEMBLY ONTO TRANSMISSION CASE (67).

IMPORTANT: DO NOT CONTACT OR BUMP SPEEDOMETER DRIVE GEAR (27) DURING INSTALLATION.

7. TORQUE EXTENSION HOUSING BOLTS (91) TO 30 N.M (22 LBS FT).

8. ROLL PIN (83) INTO OFFSET LEVER (82).

9. REVISED SPEEDOMETER DRIVEN GEAR ONTO THE VEHICLE SPEED SENSOR SHAFT UNTIL IT SNAPS INTO POSITION.

IMPORTANT: A CORRECTLY INSTALLED SPEEDOMETER DRIVEN GEAR WILL REQUIRE CERTAIN EFFORT TO REMOVE.

10. VEHICLE SPEED SENSOR INTO EXTENSION HOUSING (90).

11. TORQUE VEHICLE SPEED SENSOR RETAINER BOLT TO 10 N.M (89 LBS IN).

12. TRANSMISSION SHIFT LEVER ASSEMBLY (80) AND TORQUE BOLTS TO 17 N.M (13 LBS FT) ONTO EXTENSION HOUSING (90).

13. TRANSMISSION ASSEMBLY INTO VEHICLE.

IMPORTANT: FILL TRANSMISSION ASSEMBLY WITH DEXRON IIE OR DEXRON III AUTOMATIC TRANSMISSION FLUID (ATF) TO THE PROPER LEVEL.

14. REPLACE CRUISE CONTROL MODULE WITH REVISED CRUISE CONTROL MODULE, PART NUMBER 25162757. SEE REPLACEMENT PROCEDURE UNDER "CRUISE CONTROL MODULE REPLACEMENT" SHOWN BELOW.

CONDITION II

A REVISED CALIBRATION CRUISE CONTROL MODULE WITH A LOWER GAIN IS AVAILABLE TO REDUCE ITS SENSITIVITY OR RESPONSE TO THE VEHICLE SPEED SIGNAL.

REPLACE CRUISE CONTROL MODULE WITH REVISED CRUISE CONTROL MODULE, PART NUMBER 25162757. SEE REPLACEMENT PROCEDURE UNDER "CRUISE CONTROL MODULE REPLACEMENT" SHOWN BELOW.

CONDITION III

A REVISED CALIBRATION CRUISE CONTROL MODULE WITH A HIGHER GAIN IS AVAILABLE TO IMPROVE SENSITIVITY TO THE VEHICLE SPEED SIGNAL.

REPLACE CRUISE CONTROL MODULE WITH REVISED CRUISE CONTROL MODULE, PART NUMBER 25140613. SEE REPLACEMENT PROCEDURE UNDER "CRUISE CONTROL MODULE REPLACEMENT" SHOWN BELOW.

CRUISE CONTROL MODULE REPLACEMENT

REMOVE

BEFORE REMOVING CRUISE CONTROL MODULE, DISCONNECT CRUISE CONTROL CABLE TO OBTAIN THE NECESSARY CLEARANCE.

1. DISCONNECT CRUISE CONTROL CABLE END FITTING FROM THROTTLE BODY LEVER STUD.

IF VEHICLE IS EQUIPPED WITH ACCELERATOR CONTROL/CRUISE CONTROL CABLE ADJUSTER (THROTTLE RELAXER), REMOVE CRUISE CONTROL CABLE END FITTING FROM ADJUSTER. NOTE LOCATION OF PULLEY FOR END FITTING.

2. UNLOCK CRUISE CONTROL CABLE CONDUIT BY PULLING UP ON UNLOCK BUTTON.

3. PUSH CONDUIT TOGETHER TO OBTAIN THE ADDITIONAL CABLE SLACK.

4. REMOVE CRUISE CONTROL MODULE PER SECTION 9B OF THE SERVICE MANUAL.

IMPORTANT: IT IS NOT NECESSARY TO REMOVE CRUISE CONTROL CABLE FROM VEHICLE.

INSTALL

1. INSTALL CRUISE CONTROL CABLE TO CRUISE CONTROL MODULE PER SECTION 9B OF THE SERVICE MANUAL.

IMPORTANT: CRUISE CONTROL MODULE RIBBON MUST NOT BE TWISTED WHEN INSTALLED TO CRUISE CONTROL MODULE.

2. INSTALL CRUISE CONTROL MODULE PER SECTION 9B OF THE SERVICE MANUAL.

3. CONNECT CRUISE CONTROL CABLE END FITTING TO THROTTLE BODY LEVER STUD.

IF VEHICLE IS EQUIPPED WITH ACCELERATOR CONTROL/CRUISE CONTROL CABLE ADJUSTER (THROTTLE RELAXER), CONNECT CRUISE CONTROL CABLE END FITTING TO ADJUSTER. NOTE CORRECT LOCATION OF PULLEY FOR END FITTING.

4. ADJUST CRUISE CABLE PER "CABLE ASSEMBLY ADJUSTMENT" PROCEDURE IN SECTION 9B OF THE SERVICE MANUAL.

IMPORTANT: EXCESSIVE CABLE SLACK IN CRUISE CONTROL CABLE ASSEMBLY WILL RESULT IN PERCEIVED SLOW MODULE RESPONSE.

PARTS INFORMATION

PART NO. DESCRIPTION QUANTITY 7849818 YOKE ASSEMBLY 1 (PER DEALER) 12524068 GEAR, SPEEDO DRIVE 1 12550928 GEAR, SPEEDO DRIVEN 1 6261781 CLIP, RETAINING 1 25162757 MODULE, CRCONT 1 (CONDITIONS I AND II ONLY) 25140613 MODULE, CRCONT 1 (CONDITION III ONLY)

PARTS ARE CURRENTLY AVAILABLE FROM GMSPO.

WARRANTY INFORMATION

USE THE FOLLOWING LABOR OPERATION(S) AND CURRENT PUBLISHED LABOR TIMES. NOTE: DEPENDING ON CONDITIONS, NOT ALL LABOR OPERATIONS WILL BE USED.

LABOR OPERATION DESCRIPTION K2764 REAR HOUSING R + R / SEALER INC: R + R TRANS

K2050 GEAR, SPEEDO DRIVEN -- REPLACE

R1220 MODULE, CRCONT -- REPLACE INC: CRUISE CONTROL CABLE ADJUST

FIGURES: 4 ATTACHMENTS: 0

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.

COPYRIGHT 1995 GENERAL MOTORS CORPORATION. ALL RIGHTS RESERVED.