Preliminary Evaluation · Closed
Idle instability
Manufacturer: Ford Motor Company
What NHTSA is examining
On November 29, 2012, Ford Motor Company (Ford) initiated Customer Satisfaction Program 12N03 to extend warranty coverage terms for repair of engine idle RPM surge caused by throttle body deposits in all model year (MY) 2005 through 2007 Ford Freestyle, Five Hundred and Mercury Montego vehicles.The program extends the 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 May 31, 2013, regardless of mileage).Dealers will repair vehicles exhibiting the condition by removing and cleaning the throttle body and reprogramming the PCM with software containing an updated idle speed control strategy.According to Ford, some of the affected vehicles may experience momentary, intermittent engine idle RPM surge (idle flare) when stopped or during low speed driving maneuvers such as in a parking lot or driveway.Unstable idle speed control (dips and flares) around the target engine speed (700 rpm) can occur in vehicles with deposit build-up in the throttle body when the system adjusts engine speed in response to changes in engine load, typically from power steering application or air-conditioner compressor cycling.Idle speed control logic is only active at vehicle speeds below 3.5 mph and when the accelerator pedal is not applied.Ford testing of a vehicle with a worst case throttle body measured a maximum idle flare of 1360 RPM lasting approximately 1 second, which Ford indicated was consistent…
Vehicles under investigation
Source: NHTSA Office of Defects Investigation records, updated daily. An investigation is not a determination that a defect exists; many probes close without a recall.