EA15006 · EA
SERVICE BRAKES, HYDRAULIC:POWER ASSIST Investigation
On February 15, 2016, Ford Motor Company initiated Customer Satisfaction Program 15N05 to extend warranty coverage for the electric vacuum pump in certain model year (MY) 2011 through 2012 Ford F-150 pickup trucks equipped with 3.5L GTDI engines.The program extends coverage for up to 10 years of service or 150,000 miles from the warranty start date of the vehicle, all vehicles are eligible for the program through July 30, 2016 regardless of mileage.Ford's program covers all repairs related to electric vacuum pump (EVP) malfunctions including excessive noise, vibration, or change in brake pedal feel while applying the brakes at cold start. Ford states that the engine intake manifold is the primary source of vacuum for the brake booster and is fully compliant to motor vehicle safety standards without the supplemental vacuum supplied by the EVP.The company also contends that failure modes related to the EVP are progressive and provide warning to operators by way of noise and vibration before an operator to experience any temporary change in brake pedal feel.ODI's analysis of warranty data found that the majority of claims involved consumer concerns with EVP noise or vibration from the left front fender area when the vehicle is first started. Continued operation in this mode with pump motor noise will eventually result in the EVP seizing or becoming non-functional.Component failure analysis indicated that Ford and its supplier, Continental, identified a pump crank drive corrosion condition due to moisture entry through the vacuum intake.Corrosion damage to EVP internal components may eventually result in a blown fuse in the power distribution box and total loss of EVP function.Analysis of consumer complaints, field reports, and warranty data related to EVP failures found thatincidents predominantly occurred in driveways and parking lots in the periods immediately after cold engine starts.Many consumers operated their vehicle for some period of time with a blown EVP fuse without realizing that the pump had failed or that the vehicle had a brake system malfunction.Consumers who did experience braking performance issues reporteda temporary hard brake pedal condition at start-up followed by more consistent normal pedal feel after few seconds.On June 22, 2015, Ford developed a remedy procedure and issued TSB 15-0105 instructing dealers to replace the vacuum pump and install a new vacuum pump harness kit. In addition to reviewing test data submitted by Ford, ODI assessed safety risks associated with the alleged defect under various operating conditions, including: 1) baseline system performance with full engine and EVP vacuum available using exemplar parts, 2) disabled EVP and booster vacuum regulated to simulate worst case conditions for engine intake manifold vacuum supply to the brake booster (approximately 300 mbar); and 3) all source vacuum to the brake booster removed and Optimized Hydraulic Braking (OHB) mode active to represent complete loss of brake booster function (note: this condition is a more severe brake boost system failure mode than the alleged defect).ODI also analyzed all complaints and warranty claims to identify incidents alleging brake system performance concerns related to EVP failures.These analyses identified no brake performance issues or resulting changes in stopping distances either on highway or city traffic conditions.Two complaints alleging EVP malfunctions caused or contributed to rear-end collisions during attempted decelerations from road speeds are not believed to be related to the alleged defect.The EVP provides supplemental vacuum during initial start-up and idle
PE15026 · PE
SERVICE BRAKES, ELECTRIC Investigation
On June 22, 2015, the Office of Defects Investigations (ODI) opened Preliminary Evaluation PE15-026 to investigate incidents of increased brake pedal effort at cold start and extended stopping distance while driving in traffic, resulting from failures of the electric brake vacuum assist pump in model year (MY) 2011-2012 Ford F-150 pickup trucks equipped with 3.5L GTDI engines. In response to ODI's Information Request (IR) for PE15-026, Ford provided ODI with 396 complaints and field reports relating to incidents of increased brake pedal effort or malfunctions in the electric vacuum pump (EVP). ODI's analysis of the data provided by Ford identified 7 crashes and 1,851 warranty claims related to either a hard brake pedal condition or reduced brake effectiveness. Additionally, ODI identified one report in its database alleging an injury to an occupant of a vehicle struck in the rear by a subject F-150 vehicle with a failed EVP as documented in the police accident report referencing a dealer assessment of the pump.According to Ford, the subject vehicles utilize a traditional brake vacuum booster to provide power assist for braking and the EVP is intended to operate to maintain consistent brake pedal feel. The engine intake manifold is the primary source of vacuum for the booster and is fully compliant to motor vehicle safety standards without the EVP. Ford described the conditions related to a change in brake pedal feel as limited and temporary and provided component failure analysis showing evidence of water entry into the EVP which caused internal pump corrosion. Ford indicated that the EVP failure mode is progressive and provides warning to operators by way of noise and vibration before an operator is likely to experience any temporary change in brake pedal feel. Damage to the EVP motor bearing may eventually result in a blown EVP fuse and total loss of EVP function. Ford provided test data showing the brake pedal forces and pedal travel curves over time for 0.3g decelerations to a stop from 80kph (50mph) for: 1) normal system (full engine and EVP vacuum available); 2) Ford's approximation of worst case booster performance with EVP failure (EVP disabled and booster vacuum regulated to 300mbar to simulate cold start, all accessory loads on, and starting at 0 vacuum); and 3) with all source vacuum to the brake booster removed and Hydraulic Boost Compensation (HBC) active to represent complete loss of brake booster function. The Ford tests showed that the brake pedal forces required for achieving the 0.3g decelerations were relatively low for the normal condition, 35-40 N (8-9 lbf), increased by approximately 2-3 times normal when the EVP is disabled, 75-115 N (17-26 lbf), and increased by about 5-6 times normal for the complete brake booster failure condition, 205-215 N (46-48 lbf). This Preliminary Evaluation has been upgraded to Engineering Analysis (EA15-006) to test for EVP malfunctions under other vehicle operating conditions (e.g., low-speed driveway braking after cold-start with failed EVP), potential human factors contributions and to further assess the scope, frequency, and safety-related consequences of the alleged defect.The VOQs associated with the opening of this investigation are:10565994, 10575987, 10598351, 10604687, 10605701, 10607811, 10610491, 10615536, 10617828, 10619545, 10643075, 10650578, 10662151, 10664415, 10666988, 10668069, 10678844, 10695537, 10700874, 10706217, 10706271, 10712465, 10723033, 10723792, 10726960, 10730549, 10730721, 10730735, 10730837, 10730909, 10731008, 10731135, 10731157, 10731165, 10731395, 10731758, 10732609, 10732878, 10733375, 10733804, 10734558, 10734613, 10743859, 10744214, 10