NHTSA Office of Defects Investigation
Engineering Analysis EA18-002: Extended Braking Distance
- Closed
NHTSA's Office of Defects Investigation opened Engineering Analysis EA18-002 on April 18, 2018 and closed it on January 15, 2021. NHTSA's investigations file lists 3 models from 3 makes for it and links recall 19V-904 to it.
Updated daily from NHTSA's investigations file
Key facts
- NHTSA number
- EA18-002 (also written EA18002)
- Investigation type
- Engineering Analysis A more detailed stage of a defect investigation, opened when NHTSA's Office of Defects Investigation decides an issue merits further review, often after a Preliminary Evaluation or a Recall Query; it can include vehicle testing, surveys and further information requests.
- Status
- Closed January 15, 2021
- Opened
- Closed
- Vehicle or equipment manufacturer
- Ford Motor Company
- Component
- Service Brakes, Air — Antilock — Control Unit/Module
- Recall linked by NHTSA
- 19V-904: ABS Valve May Remain Open after ABS Event, reported
- Vehicles and equipment
- 3 models from 3 makes, including the Ford Fusion and Lincoln MKZ
NHTSA's summary
As NHTSA's Office of Defects Investigation wrote it for Engineering Analysis EA18-002.
On April 18, 2018, the Office of Defects Investigation (ODI) opened Engineering Analysis (EA) 18-002 to investigate reports of braking concerns in model year (MY) 2006-12 Ford Fusion and Lincoln MKZ, and MY 2006-11 Mercury Milan vehicles manufactured with Continental Automotive System?s ABS hydraulic control units (HCUs). Complainants report that after an ABS braking event (initiated by slippery or uneven surfaces) the brake pedal moved towards the floor and the vehicle stopping distance increased beyond driver expectations.
Inside the HCU are four hydraulic normally closed (NC) valves with zinc-coated moving armatures that control the flow of brake fluid. Unstable brake fluid can degrade over time, allow the brake fluid to gel, and corrosion to form on the armatures. The high-viscosity gelation and corrosion can cause the armatures to become stuck (open). In some cases, braking returns to normal when the armature(s) subsequently become unstuck. The intermittent condition proves difficult to diagnose with complainants reporting having (non-HCU) repairs conducted only to have the condition return.
During the investigation, 14 HCUs from complaint vehicles were recovered, including seven from reported crashes. NHTSA?s Vehicle Research and Test Center (VRTC) disassembled the HCUs, removed the four NC valves in each, and confirmed 22 of the 56 NC valves contained stuck armatures. On seven of the 14 HCUs, both front wheel armatures were stuck, on nine of the 14 HCUs two or three armatures were stuck. And 52 of the 56 NC armatures exhibited corrosion of the zinc coating. Forces required to extract stuck armatures from the valve sleeve were measured to range from 1.1 to 18.0 lbs. VRTC also conducted ABS braking tests on a variety of test surfaces that showed HCU failures cause increases in pedal travel and braking distances. Testing also showed that if the driver was able to apply four times the brake pedal force and two times the brake pedal travel, then high-vehicle decelerations could be achieved, however, single or multiple wheel lockups were also occurring.
Based on Ford?s response to ODI?s July 20, 2018 information request letter, and complainants' reports to NHTSA, ODI identified a population of vehicles with an elevated level of field failure compared to vehicles produced both before and after.
Further evaluation of Ford?s response identified that the brake fluid used to produce these vehicles, a specific formulation of a DOT3 fluid provided by CCI Corporation between February 2006 and July 2009, differed from the brake fluid used in other vehicle populations. ODI used the correlation of fluid specification and elevated field failures to identify a vehicle population exhibiting a defect trend. The complaints, crashes and injuries cited above, and the 14 recovered HCUs involve vehicles from this population.
On December 18, 2019, Ford submitted safety recall (19V-904) to remedy HCU failures on the MY 2006-2010 Ford Fusion, Lincoln MKZ, and Mercury Milan vehicles manufactured with the suspect CCI brake fluid formulation. Ford will function test the HCU and replace the DOT 3 brake fluid with an improved DOT 4 brake fluid. If the HCU fails the function test, Ford will install an HCU with a different armature coating (black oxide). HCUs with black oxide coating were fully phased into Ford?s new vehicle production by MY 2016; these HCUs do not appear to be experiencing armature corrosion. ODI notes that the non-recalled EA18-002 subject vehicles, which were manufactured with a different specification brake fluid, did not display an elevated level of field failures like the recalled vehicles.
Based on available information, Ford?s rec
Vehicles and equipment listed for this investigation
NHTSA's investigations file lists these vehicles and equipment for Engineering Analysis EA18-002. A listed model year means only that an investigation names it; it says nothing about any particular vehicle. Model years with a try.vin recall page link to that page's NHTSA investigations section.
What an NHTSA investigation is
NHTSA's Office of Defects Investigation (ODI) looks into possible safety defects in vehicles and equipment, often after owner complaints. An investigation usually starts as a Preliminary Evaluation, or as a Recall Query when it concerns whether an existing recall covers the right vehicles or fixes the problem, and ODI can upgrade it to a more detailed Engineering Analysis. A Defect Petition asks NHTSA to open an investigation, and Audit and Equipment Queries are administrative investigations into whether companies complied with federal vehicle safety requirements, such as reporting, recall and certification rules.
An open investigation is not a finding that a safety defect exists, and NHTSA can close one without a recall.
To see whether a specific vehicle has an open recall, enter its VIN at nhtsa.gov/recalls.
Free VIN check: decode a VIN to see its year, make and model.
Sources
NHTSA's investigation record for EA18-002
Investigation details come from NHTSA's investigations file, which try.vin imports once a day. The investigation types are described from the U.S. Department of Transportation Inspector General's May 2023 report on NHTSA's Office of Defects Investigation, NHTSA's petition rules (49 CFR Parts 552 and 557) and NHTSA's Office of Defects Investigation procedures. How try.vin reads NHTSA investigations.