Investigations
THROTTLE STICKING CLOSED
NHTSA Engineering Analysis EA02015 - closed, opened 2002-08-01.
NHTSA investigation EA02015 is a Engineering Analysis opened on 2002-08-01 and currently closed. The subject is tracked inside the Office of Defects Investigation queue. Latest activity on this investigation was logged on 2004-01-12 - NHTSA updates that field whenever an Information Request goes out, a supplement is filed, or a status change is recorded in the public docket.
An Engineering Analysis like EA02015 is the deeper technical phase that follows a PE. NHTSA requests design, warranty, and field-failure data from the manufacturer, conducts its own testing when needed, and determines whether the evidence supports a safety defect finding that would compel a recall.
Investigators summarized the matter as follows: "THIS INVESTIGATION INVOLVES THE GENERAL MOTORS CORPORATION (GM) THROTTLE BODY (TB) UTILIZED IN MODEL YEAR (MY) 1999-2002 SILVERADO, SIERRA, TAHOE, SUBURBAN, AVALANCHE AND YUKON (SUBJECT VEHICLE(S)) WITH 4.8L, 5.3L, AND 6..." Investigations are the early-warning layer of the federal auto-safety system, sitting upstream of formal recalls and defect orders. Whether this one closes without action or escalates into an Engineering Analysis, the full history stays in the ODI archive so researchers, litigators, and buyers can pull the paper trail at any time.
Investigation Summary
THIS INVESTIGATION INVOLVES THE GENERAL MOTORS CORPORATION (GM) THROTTLE BODY (TB) UTILIZED IN MODEL YEAR (MY) 1999-2002 SILVERADO, SIERRA, TAHOE, SUBURBAN, AVALANCHE AND YUKON (SUBJECT VEHICLE(S)) WITH 4.8L, 5.3L, AND 6.0L ENGINES. THE TB VALVE MAY INTERMITTENTLY STICK IN A CLOSED POSITION. IN SUCH A SITUATION, AN OPERATOR MAY APPLY ADDITIONAL ACCELERATOR PEDAL FORCE TO INCREASE ENGINE SPEED. THE APPLICATION OF ADDITIONAL ACCELERATOR PEDAL FORCE, TO OPEN A STUCK THROTTLE VALVE, MAY OPEN THE THROTTLE VALVE MORE THAN INTENDED AND, IN TURN, ACCELERATE THE ENGINE AND VEHICLE MORE THAN INTENDED AND REASONABLY EXPECTED BY THE DRIVER. ON AUGUST 1, 2002, THE OFFICE OF DEFECTS INVESTIGATION (ODI), OF THE NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION (NHTSA), OPENED THIS ENGINEERING ANALYSIS. THE INVESTIGATION REVEALED THAT TWO FACTORS MAY CAUSE THE DEFECT: 1) TB MANUFACTURING PROCESS PROBLEMS; AND 2) ACCUMULATION OF DEPOSITS (A PCV SYSTEM BY-PRODUCT) ON OR AROUND THE TB THROTTLE VALVE AND BORE. ODI CONCLUDES THAT THE TB PERFORMS IN A DEFECTIVE MANNER AFTER ANALYZING GM¿S DATA SUBMISSIONS, AND TEST DATA COLLECTED BY THE VEHICLE RESEARCH AND TEST CENTER (VRTC). FIFTY-NINE CRASHES ARE ALLEGED TO HAVE OCCURRED AS A RESULT OF GM¿S TB DEFECT. THE MAJORITY OF THE CRASHES INVOLVE A SINGLE VEHICLE, ENGAGING IN A CLOSE QUARTER VEHICLE MANEUVER (OR LOW SPEED), AND CAUSING ONLY MINOR PROPERTY DAMAGE. FOUR OUT OF THE FIFTY-NINE CRASHES INVOLVE INJURY, AND THOSE INJURIES WERE MINOR. ALTHOUGH GM¿S TB IS DEFECTIVE, BASED ON THE EVIDENCE GATHERED, ODI HAS FOUND THAT THE ACCELERATOR PEDAL FORCE REQUIRED TO OPEN A STUCK THROTTLE VALVE IS NEGLIGIBLE, AND THE THROTTLE VALVE DOES NOT STICK IN THE OPEN POSITION. THEREFORE THIS ENGINEERING ANALYSIS (EA02-015) WILL BE CLOSED AT THIS TIME. THE CLOSING OF THIS INVESTIGATION DOES NOT CONSTITUTE A FINDING BY NHTSA THAT A SAFETY-RELATED DEFECT DOES NOT EXIST. FOR A DETAILED DISCUSSION OF THE TB COMPONENT AND TESTING, PLEASE SEE THE ATTACHED REPORT.
About This Investigation Type
An Engineering Analysis (EA) is the in-depth phase following a Preliminary Evaluation. NHTSA engineers conduct testing, collect data from manufacturers, and perform detailed technical analysis to determine whether a safety defect exists. An EA may lead to a voluntary recall by the manufacturer or, in rare cases, a mandatory recall order.
Data from NHTSA Office of Defects Investigation. Cross-references: NHTSA recall campaign API and NHTSA FARS where fatality records overlap. PlainCars does not rate or recommend vehicles. about how PlainCars sources NHTSA data.
Read our methodology - how this data is sourced, computed, and verified.