Investigations
WATER/ICE IN BRAKE BOOSTER
NHTSA Preliminary Evaluation PE07018 - closed, opened 2007-04-03 and involving the VOLKSWAGEN VOLKSWAGEN.
NHTSA investigation PE07018 is a Preliminary Evaluation opened on 2007-04-03 and currently closed. The subject of record is VOLKSWAGEN VOLKSWAGEN, which places this file inside the Office of Defects Investigation queue for VOLKSWAGEN. Latest activity on this investigation was logged on 2007-09-04 - NHTSA updates that field whenever an Information Request goes out, a supplement is filed, or a status change is recorded in the public docket.
A Preliminary Evaluation like PE07018 is the entry point of the federal defect-investigation process. NHTSA engineers scan complaint databases, field reports, and manufacturer data to decide whether an Engineering Analysis is warranted, whether a voluntary recall is already sufficient, or whether the pattern does not rise to a defect finding.
Investigators summarized the matter as follows: "DURING THIS INVESTIGATION, VOLKSWAGEN OF AMERICA (VW) IDENTIFIED A PROBLEM WITH WATER ACCUMULATION IN THE FRESH AIR PLENUM THAT COULD, IN CERTAIN CIRCUMSTANCES, RESULT IN REDUCED BRAKE POWER ASSIST IN MODEL YEAR (MY) 200..." 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. Related VOLKSWAGEN files, listed below, give context on whether this is an isolated concern or part of a broader pattern across the brand.
Investigation Summary
DURING THIS INVESTIGATION, VOLKSWAGEN OF AMERICA (VW) IDENTIFIED A PROBLEM WITH WATER ACCUMULATION IN THE FRESH AIR PLENUM THAT COULD, IN CERTAIN CIRCUMSTANCES, RESULT IN REDUCED BRAKE POWER ASSIST IN MODEL YEAR (MY) 2002 PASSAT VEHICLES. VW INDICATED THAT PROBLEM IS CAUSED BY LEAVES AND OTHER DEBRIS CLOGGING THE PLENUM DRAINS, WHICH MAY RESULT IN WATER FILLING THE PLENUM TO THE LEVEL OF THE BRAKE BOOSTER AIR INTAKE. THE BOOSTER AIR INTAKE IS LOCATED IN THE FRESH AIR PLENUM IN THE MY 2002 PASSAT VEHICLES, BUT NOT IN THE MY 2001 OR 2003 VEHICLES WHICH DRAW BOOSTER AIR FROM THE CABIN. VW TESTING SHOWED THAT BRAKE ASSIST COULD BE REDUCED IF WATER ENTERS THE BOOSTER AND FREEZES. VW IS ADDRESSING THE PROBLEM WITH A SERVICE CAMPAIGN, WHICH BEGAN IN AUGUST 2007. THE FRESH AIR PLENUM IN THE SUBJECT VEHICLES IS AN ENCLOSED SPACE AT THE BASE OF THE WINDSHIELD FROM WHICH THE VEHICLE VENTILATION SYSTEM DRAWS THE FRESH AIR SUPPLY VIA A POLLEN FILTER. RAIN WATER THAT FLOWS OFF THE WINDSHIELD INTO THE PLENUM IS DRAINED THROUGH TWO VALVES LOCATED BELOW THE BATTERY AND BRAKE BOOSTER. STRAINERS AT THE BASE OF THE WINDSHIELD AND IN THE PANEL COVERING THE TOP OF THE PLENUM BLOCK LEAVES, PINE NEEDLES AND OTHER DEBRIS. OVER TIME, DEBRIS MAY ENTER THE PLENUM THROUGH OPENINGS IN THE PLENUM PANEL OR AROUND THE HOOD HINGES. IF CLOGGED DRAINS ALLOW APPROXIMATELY 3-4 GALLONS OF WATER TO ACCUMULATE IN THE PLENUM, THE WATER MAY ENTER THE BOOSTER THROUGH THE AIR INTAKE. WATER ACCUMULATION IN THE PLENUM MAY ALSO RESULT IN COMPLAINTS OF WET CARPETS IN THE VEHICLE INTERIOR IF THE WATER REACHES THE LEVEL OF THE FRESH AIR INTAKE/POLLEN FILTER. VW STATED THAT ITS TESTING SHOWED THAT BRAKE PERFORMANCE AND ACTUATING FORCE (I.E., PEDAL EFFORT) ARE NOT AFFECTED WHEN THE BOOSTER IS FILLED WITH THE MAXIMUM AMOUNT OF WATER POSSIBLE (UP TO THE HEIGHT OF THE BOOSTER ENGINE VACUUM CONNECTION, THROUGH WHICH WATER DRAWN INTO THE BOOSTER IS EVACUATED). VW'S TESTING SHOWED THAT BRAKE PERFORMANCE AND ACTUATING FORCE
About This Investigation Type
A Preliminary Evaluation (PE) is the first phase of NHTSA's investigation process. It is opened when the agency identifies a potential safety defect pattern, usually triggered by consumer complaints, manufacturer reports, or field monitoring. During a PE, NHTSA gathers information to determine whether a formal engineering analysis is warranted.
Other VOLKSWAGEN Investigations
Inadvertent Automatic Emergency Braking
Inadvertent Door Opening
Fuel Leak due to Suction Jet Pump Failure within Fuel Tank (Remedy Effectiveness of Recall 16V647)
Inadvertent Automatic Emergency Braking
LGES High Voltage Battery Failures
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.