CLICKING NOISE UNDER DASH OR HOOD. Cadillac Eldorado 1995

SUBJECT: CLICKING NOISE UNDER DASH OR HOOD (CLEAN AND RELEARN THROTTLE BODY BORE AND BLADE)

MODELS: 1995 CADILLAC CONCOURS, ELDORADO AND SEVILLE WITH 4.6L ENGINE (VINS Y, 9 - RPOS L37, LD8)

1995 OLDSMOBILE AURORA WITH 4.0L ENGINE (VIN C - L47)

CONDITION:

DURING A "KEY ON" OR "KEY OFF," THE ISC MOTOR MAY RATCHET. THE CONDITION MAY BE IDENTIFIED AS A CLICKING NOISE UNDER DASH OR HOOD. THE DURATION OF THIS RATCHETING MAY BE UP TO 20 SECONDS. THE RACHETING CONDITION MAY OCCUR MORE FREQUENTLY WHEN STARTING THE ENGINE COLD OR AT HIGHER ALTITUDES.

CAUSE:

THE ISC MOTOR RATCHETING IS CAUSED WHEN THE MOTOR IS COMMANDED TO EXTEND BEYOND ITS MECHANICAL LIMIT. WHEN THE TP SENSOR LEARN IS CORRECT (AT MINIMUM AIR, THE THROTTLE LEVER RESTS ON THE MINIMUM AIR SCREW) AND THE ISC MAXIMUM EXTEND POSITION IS PROPERLY ADJUSTED, THE MOTOR WILL NOT BE COMMANDED TO MOVE BEYOND THE MECHANICAL LIMIT.

CORRECTION:

THE THROTTLE BODY BORE AND BLADE SHOULD BE CLEANED AND RELEARNED USING THE FOLLOWING PROCEDURE:

IMPORTANT: IF IT IS SUSPECTED THAT THE ISC MAXIMUM EXTEND POSITION HAD BEEN ADJUSTED WITHOUT CLEANING THE BORE, IT SHOULD BE CHECKED AND READJUSTED IF REQUIRED. CLEANING THE THROTTLE BORE SHOULD BE PERFORMED BEFORE PERFORMING THE IDLE SPEED CONTROL SYSTEM CHECKING PROCEDURE.

THROTTLE BODY CLEANING PROCEDURE

**REMOVE OR DISCONNECT** AIR INTAKE DUCT FROM THROTTLE BODY.

**INSPECT** THROTTLE BODY BORE AND THROTTLE VALVE PLATE FOR DEPOSITS. IT IS NECESSARY TO OPEN THE THROTTLE VALVE TO INSPECT ALL SURFACES.

**CLEAN** THROTTLE BODY BORE AND THROTTLE VALVE PLATE USING A CLEAN SHOP TOWEL WITH GM TOP ENGINE CLEANER, P/N 1052626 OR AC-DELCO CARBURETOR TUNE-UP CONDITIONER, P/N X66-P, OR EQUIVALENT PRODUCT.

NOTICE: DO NOT USE ANY SOLVENT THAT CONTAINS METHYL ETHYL KETONE (MEK). THIS SOLVENT MAY DAMAGE FUEL SYSTEM COMPONENTS.

FOR G-CAR: **INSTALL OR CONNECT** 1. AIR INTAKE DUCT AT THROTTLE BODY. 2. RUN TECH 1 TP SENSOR AND IDLE LEARN PROCEDURE.

FOR E, K, AND/OR K-SPECIAL: **INSTALL OR CONNECT** 1. AIR INTAKE DUCT AT THROTTLE BODY. 2. ENTER DIAGNOSTICS; SELECT PCM OVERRIDE PS13. 3. PRESS THE "COOLER" BUTTON. 4. KEY "OFF" FOR 30 SECONDS (DO NOT EXIT DIAGNOSTICS). 5. PERFORM TP SENSOR/IDLE LEARN PROCEDURE.

WARRANTY INFORMATION:

FOR VEHICLES REPAIRED UNDER WARRANTY, USE: LABOR OPERATION: J5480 LABOR TIME: .9 HRS.

FIGURES: 0 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.