EXCESSIVE TICKING NOISE IN AMBIENT TEMP. (DIAG REPL.. Chevrolet Tahoe

SUBJECT: EXCESSIVE TICKING NOISE IN AMBIENT TEMPERATURE (DIAGNOSE, REPLACE EVAP PURGE SOLENOID VALVE)

MODELS: 1997-98 CHEVROLET AND GMC C/K, M/L, S/T, P AND G MODELS 1997-98 OLDSMOBILE BRAVADA WITH 4.3L, 5.0L, 5.7L, 7.4L ENGINE (VINS W, X, M, R, J - RPOS L35, LF6, L30, L31, L29)

CONDITION:

SOME OWNERS MAY COMMENT ON AN EXCESSIVE "TICKING" NOISE UNDER CERTAIN AMBIENT TEMPERATURES AND DRIVING CONDITIONS. OWNER MAY DESCRIBE A SOUND SIMILAR TO SPARK DETONATION.

NO DTC'S ARE SET, NO DRIVEABILITY SYMPTOMS, OR EMISSION CONCERNS ARE RELATED TO THIS NOISE ISSUE.

CAUSE:

THE "TICK" NOISE MAY BE GENERATED BY THE ACTION OF THE PLUNGER HITTING THE PORT SEAT. THE STOP CUSHION GENERATES THE NOISE, WHICH MAY BE MORE NOTICEABLE UNDER LOW TEMPERATURES.

CORRECTION:

AN IMPROVED EVAP (EMISSION CANISTER) PURGE SOLENOID VALVE, P/N 1997277, HAS BEEN RELEASED FOR THE ABOVE CONDITION. THE NEW VALVE APPEARS IDENTICAL TO THE UNIT IT REPLACED. SEE FIGURE 1--EVAP PURGE SOLENOID VALVE, FOR LOCATION AND P/N IDENTIFICATION.

WHEN DIAGNOSING A SUSPECTED EVAP PURGE SOLENOID VALVE FOR NOISE:

1. CHECK FOR ANY STORED DTC'S.

2. DISCONNECT THE ELECTRICAL CONNECTOR (1) TO THE EVAP PURGE SOLENOID VALVE AND DRIVE THE VEHICLE.

NOTE: THIS MAY SET A DTC P0440 (EVAP EMISSION CONTROL SYSTEM MALF.) IF THIS TEST IS CONDUCTED DURING A COLD ENGINE START-UP.

3. IF THE NOISE IS GONE, THE EVAP PURGE SOLENOID VALVE (5) IS THE SOURCE OF THE NOISE AND SHOULD BE REPLACED, AS PER THE SERVICE MANUAL PROCEDURE. IF THE NOISE IS STILL PRESENT, CONTINUE TO DIAGNOSE THE CONCERN USING STANDARD DIAGNOSTIC PROCEDURES.

4. CLEAR DTC P0440, IF SET DURING THE ABOVE PROCEDURE.

(INSERT RMVALVE01)

PARTS INFORMATION:

PART NUMBER DESCRIPTION 1997277 EVAP EMISSION CANISTER PURGE SOLENOID VALVE

PARTS ARE CURRENTLY AVAILABLE FROM GMSPO.

WARRANTY INFORMATION:

FOR VEHICLES REPAIRED UNDER WARRANTY, USE:

LABOR CODE LABOR DESCRIPTION MODEL LABOR TIME _____ _________________ _____ __________ J6400 SOLENOID, FUEL VAPOR C/K 0.2 HR CANISTER PURGE CONTROL- REPLACE G 0.4 HR

M/L 0.4 HR

P 0.2 HR

S/T 0.2 HR

ADD: DIAGNOSTIC TIME: YOU MAY CLAIM 0.0 TO 0.3 HR DEPENDING ON ACTUAL TIME PERFORMING DIAGNOSIS.

FUTURE LABOR TIME GUIDES WILL BE UPDATED WITH THIS LABOR CODE.

FIGURES: 01 ATTACHMENTS: 00

FIGURE 1 - EVAP PURGE SOLENOID VALVE AND P/N IDENTIFICATION LEGEND

1 - ELECTRICAL CONNECTOR 4 - INTAKE MANIFOLD (V6 SHOWN) 2 - PURGE SOLENOID RETAINING BOLTS 5 - EVAP PURGE SOLENOID VALVE 3 - LOCATION OF PART NUMBER 6 - HOSE CONNECTION

Object Number: 336304 Size: LF

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.