— Nissan Murano soft brake pedal complaints caused a federal investigation in 2017 that has now been closed by the National Highway Traffic Safety Administration.
Nearly 60 complaints had been filed by 2017 regarding 2009 Nissan Murano soft brake pedals that went to the floors as they lost pressure.
NHTSA believed there may have been problems with the antilock braking system hydraulic control units which control hydraulic pressure to the Murano brake assemblies.
Federal safety regulators upgraded the Murano soft brake pedal investigation in April 2018 after drivers of 2009 Nissan Murano SUVs complained about extended stopping distances.
NHTSA says the ABS hydraulic control unit allegedly caused the problem, a control unit manufactured by tier-one supplier Continental.
According to NHTSA:
"The corrosion-preventive, zinc coating used on the armatures of the normally closed (NC) valves within ABS HCU may react with brake fluids lacking sufficient corrosion-preventative additives. This reaction can cause the formation of a gelatinous material, which may cause the NC valves to close slowly."
Investigators say the gel can solidify so much the spring used to return the valve to the closed position may not be able to overcome the gel buildup, allowing the NC valve to remain open. NHTSA found if any of the four NC valves remain open, brake fluid will be diverted to one or two accumulators.
This can cause a soft brake pedal but not a total loss of braking force.
Nissan launched a customer service campaign for 2019 Muranos built before November 1, 2007, but the automaker later included all 2009 Murano SUVs.
During the investigation, the government eventually found brake complaints, two crashes and four injuries allegedly caused by Nissan Murano brake problems. In addition, Nissan reported 870 complaints and 16 crashes allegedly caused by 2009 Murano soft brake pedals and extended stopping distances.
The automaker issued a 2009 Nissan Murano recall which began February 7, 2019. Nissan dealers were told to flush the brake systems with DOT 4 brake fluid and test the hydraulic control units to check for stuck valves. The hydraulic control units would also be replaced if necessary.
Nissan also announced a customer service program for owners of 2010-2014 Murano SUVs to inspect the zinc-coated armatures and using the same recall procedures.
NHTSA found new Continental hydraulic control units were used in new vehicle production after December 2014 and do not appear to be experiencing corrosion.
According to NHTSA, the recall and customer service programs appear to fix the Nissan Murano soft brake pedal problems. And although the investigation is now closed, safety regulators say they may reopen the probe if circumstances change.