2001 Chevrolet Silverado 2500 Hd

IN A LETTER DATED NOVEMBER 7, 2007, GENERAL MOTORS (GM) REPORTED TO THE OFFICE OF DEFECTS INVESTIGATION (ODI) THAT IT WILL CONDUCT A SAFETY RECALL (07V-521) TO REPLACE THE CRANK POSITION SENSOR (CKP) IN APPROXIMATELY 12,000 MODEL YEAR (MY) 2001 CHEVROLET SILVERADO AND GMC SIERRA VEHICLES EQUIPPED WITH 8.1 LITER ENGINES MANUFACTURED ON OR BEFORE NOVEMBER 15, 2000.ACCORDING TO GM, THE CKP CAN FAIL INTERMITTENTLY OR PERMANENTLY.A PERMANENT CKP FAILURE WOULD RESULT IN AN ENGINE STALL WITHOUT RESTART.AN INTERMITTENT CKP FAILURE COULD CAUSE THE SERVICE ENGINE SOON LIGHT TO ILLUMINATE, THE VEHICLE TO RUN ROUGH OR THE ENGINE TO STALL BUT ALLOWS RESTART.AS A REMEDY, AN IMPROVED CKP WILL BE INSTALLED IN THE SUBJECT VEHICLES.THE RECALL CAMPAIGN WILL START IN DECEMBER 2007. DURING THE PRELIMINARY EVALUATION (PE06-016), AND THIS EA INVESTIGATION, GM AND ODI INDEPENDENTLY CONDUCTED DETAILED REVIEWS OF CERTAIN FIELD DATA TO UNDERSTAND THE NATURE AND RATE OF SUBJECT VEHICLE STALLING DUE TO CKP FAILURES.GM AND ODI REVIEWED GM'S WARRANTY CLAIMS FOR THE CKP WITH THE OBJECTIVE OF ASCERTAINING AN ESTIMATE OF THOSE CLAIMS REPRESENTING AN ENGINE STALL WHILE DRIVING.THE CKP WARRANTY CLAIMS WITHOUT VERBATIM TEXT WERE THE LARGEST SEGMENT OF WARRANTY CLAIMS.USING THOSE CLAIMS, GM SURVEYED VEHICLE OWNERS TO GATHER ADDITIONAL INFORMATION TO DETERMINE IF THE CLAIM WAS ASSOCIATED WITH A STALL WHILE DRIVING EVENT.BASED ON THE SURVEY, GM ESTIMATED THAT APPROXIMATELY 49% OF ALL WARRANTY REPAIRS FOR THE CKP INVOLVED A STALL WHILE DRIVING.ODI?S REVIEW OF GM'S SURVEY DATA PRODUCED A HIGHER ESTIMATE (71%) FOR STALL WHILE DRIVING.GM FURTHER ESTIMATED THE RATE OF STALL WHILE DRIVING FOR THE SUBJECT VEHICLES OVER TIME.IT ESTIMATED STALLING WHILE DRIVING RATES OF 1.6%, 4.6% AND 8.9% AT 1, 3 AND 6 YEARS IN SERVICE RESPECTIVELY.ODI'S REVIEW OF THE GM'S SURVEY DATA FINDS HIGHER ESTIMATED STALL WHILE DRIVING RATES OF 2.2%, 6.8% AND 13% AT 1, 3 AND 6 YEARS IN SERVICE RESPECTIVELY. ODI ALSO CONDUCTED A SURVEY OF VEHICLE OWNERS USING CONSUMER COMPLAINTS REPORTED TO BOTH ODI AND GM.THE OBJECTIVE WAS TO ASCERTAIN THE POTENTIAL SAFETY CONSEQUENCES OF AN ENGINE STALL DUE TO THE ALLEGED DEFECT.WITH RESPECT TO THE ABILITY TO RESTART THE VEHICLE AFTER A STALL, 11% REPORTED IMMEDIATE RESTART, 69% REPORTED DELAYED RESTART AND 20% REPORTED NO RESTART.OVER HALF NOTED AT LEAST ONE ENGINE STALL INCIDENT AT SPEEDS IN EXCESS OF 40MPH. ABOUT ONE-THIRD NOTED THE VEHICLE WAS STRANDED EITHER PARTIALLY OR FULLY IN A LANE OF TRAFFIC AFTER THE ENGINE STALL.ALL OF THE CONSUMERS SURVEYED NOTED MULTIPLE STALLING EVENTS PRIOR TO PROPER DIAGNOSIS AND REPLACEMENT OF THE CKP.BASED ON GM'S DECISION TO CONDUCT A SAFETY RECALL, THIS INVESTIGATION IS CLOSED.

GM IS CONDUCTING A RECALL ON ALL SUBJECT VEHICLES BUILD BETWEEN MAY 1999 AND OCTOBER 14, 1999.SIGNIFICANT CHANGES WERE INCORPORATED INTO PRODUCTION IN EARLY OCTOBER 1999, AND VEHICLES BUILT AFTER THAT DATE HAVE LOWER WARRANTY FAILURE RATES.THE COMPLAINT AND WARRANTY DATA APPEAR TO SUPPORT THE EFFECTIVENESS OF THESE CHANGES. GM MADE ADDITIONAL CHANGES IN NOVEMBER 1999, FEBRUARY 2000, MAY 2001, AND FEBRUARY 2004.ODI WILL CONTINUE TO MONITOR THIS PROBLEM AND WILL TAKE FURTHER ACTION, IF WARRANTED, IN THE FUTURE.FOR FURTHER TECHNICAL DETAILS SEE THE ATTACHED ENGINEERING ANALYSIS REPORT.

THE PRELIMINARY EVAULATION IS BEING UPGRADED.DURING THE EA ODI WILL LIMITITS INVESTIGATION TO ONLY THOSE VEHICLES EQUIPPED WITH A HYDRO-BOOST SYSTEM, WHICH PROVIDES POWER ASSIST TO THE BRAKING AND STEERING SYTEMS.VACCUUM BRAKE BOOSTER VEHICLES ARE EXCLUDED.ODI HASEXPANDED THE SCOPE OF THE EA TO INCLUDE MODEL YEARS2003 AND 2004, ASDURING THE PE, ODI LEARNED THAT THE HYDROBOAST PUMPS WERE MODIFIED IN FEBRAURY 2004.THEREFORE,ODI HAS EXPANDED THE SCOPE TO INCLUDE THE ADDITIONAL MODEL YEARS.ODI'S IS CONCERNED BECAUSE THISISA SUDDEN FAILURE THAT AFFECTS TWO CRITICAL SYSTEMS OF THE VEHICLE, BRAKES AND STEERING, AT THE SAME TIME.THE ABILITY OF THE OPERATOR TO HANDLE THE DUAL FAILURES IS A CONCERN. FURTHER, THESE VEHICLES TEND TO BE WORK VEHICLES, WITH SOME OVER 10,000 POUNDS GVWR AND MANY EQUIPPED TO PULL LARGE TRAILERS.DUAL FAILURES OF HEAVILY LOADED VEHICLES AND VEHICLES PULLING TRAILERS FURTHER INCREASES THE SAFETY RISK.ODI PLANS TO CONDUCT TESTING TO QUANTIFY THE BRAKING AND STEERING PERFORMANCE DEGRADATION AND THE IMPACT ON SAFE VEHICLE CONTROL, WHEN A HYDROBOAST PUMP FAILS.