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U.S. closes Ford, GM defect probes into 600K cars

David Shepardson
Detroit News Washington Bureau

The National Highway Traffic Safety Administration said Tuesday it is closing two defect investigations into 502,000 Ford cars and 100,000 General Motors cars without demanding recalls.

The safety agency said it was ending its investigation opened in July into 502,410 2004-07 Ford Crown Victoria, Mercury Grand Marquis and Marauder cars after nine complaints alleging incidents of interference between dislodged exhaust manifold heat shields and the lower steering shaft/knuckle, including one alleging the interference resulted in a crash on a highway entrance ramp. The single crash could not be verified and the description of the crash in the complaint was not supported by the police accident report.

In September, Ford identified 10 additional incidents resulting in a low rate of 1.6 incidents per 100,000 vehicles sold in vehicles ranging from seven to 11 years in service. Six of these incidents were reported by a single source, a state police fleet that corrected the problems in March 2011 and has not reported any additional failures since. Ford also reported five warranty claims, but these incidents occurred at very low mileages and appeared to be caused by loose or missing heat shield attachment hardware rather than rust, NHTSA said. NHTSA “will continue to monitor complaints and other information relating to the alleged defect in the subject vehicles and take further action in the future if warranted.”

Separately, the safety agency said it is closing an investigation opened in April into 105,765 2014 Chevrolet Impala cars over allegations of inappropriate autonomous braking while driving, resulting in unexpected sudden and rapid deceleration in traffic. The investigation was based on two complaints alleging incidents of sudden and severe non-commanded braking resulting in rear impact collisions.

NHTSA analyzed all complaints related to allegations of unwanted brake activations while driving that were provided by GM or submitted to NHTSA from consumers and has not identified any additional incidents involving sudden, extended — greater than 1 second — autonomous braking. The two crash complaints involved rental vehicles equipped with an Electric Park Brake system — but not autonomous driving functions.

NHTSA noted that neither vehicle was equipped with Full Speed Range Adaptive Cruise Control or Forward Collision Alert systems. Brake lights will be illuminated if the service brakes are applied or the EPB system is activated while the vehicle is moving, GM told NHTSA. When the Electric Park Brake system is engaged, the Electric Brake Control Module initiates a controlled deceleration while activating a chime and a telltale light.

“Witness statements and analysis of crash data from the two incidents are consistent with inadvertent dynamic EPB brake applications. Both reports alleged beeping noise immediately before the accidents and one pre-crash data report shows a moderate initial vehicle deceleration,” NHTSA said.

GM’s testing and part examination did not find any evidence of mechanical or electrical failure of the EPB switches and GM did not identify any faults in the subject components or systems that could have caused or contributed to autonomous brake applications. GM said the “evidence indicates the events were caused by inadvertent driver actuation of the EPB switch.”

During the investigation, GM identified a defect in the EPB software in 132,921 2014-15 Chevrolet Impala and 2013-15 Cadillac XTS cars that could result in failure of the EPB to release after vehicle start-up. In this condition, the electronic parking brake piston arm may not fully retract when the driver disengages the EPB, which may cause the brake pads to stay partially engaged with the rotor.

In the recall issued in September, GM and its supplier, Mando Pyeongtaek, upgraded the EPB software to address brake drag conditions and instructed dealers to reprogram the electronic parking brake control module on the recalled vehicles.