Electronic throttle body systems are designed to shut down if a malfunction occurs, like a sticking throttle blade.
The Mazda Tribute is a sibling to the Ford Escape which is under investigation by NHTSA for failing electronic throttle body malfunction that may one day result in a recall;
On February 21, 2013, the Office of Defects Investigations (ODI) opened Preliminary Evaluation PE13-003 to investigate allegations of electronic throttle body (ETB) failures resulting in sudden reduction of engine power in model year (MY) 2009-2013 Ford Escape, Fusion, Mariner and Milan vehicles. During this investigation, Ford identified a condition in subject vehicles equipped with 2.5L and 3.0L engines that may result in a sudden reduction of engine power. According to Ford, the ETB internal motor contacts may develop a high resistance material buildup condition on the commutator, resulting in intermittent electrical connectivity and reduced engine power. When this condition occurs, the Malfunction Indicator Lamp (MIL) or Wrench light will illuminate and the vehicle may enter a limited limp home mode. Ford?s trade name for the feature is Failure Mode Effects Management (FMEM) mode. In this mode, engine power and vehicle speed are reduced, while full function of the power steering, power braking, lighting, and climate control systems are maintained.
ODI?s complaint analysis indicate that the predominant failure mode involved reduced motive power associated with the limited limp home mode with engine speeds limited to approximately 900 RPM. Analysis of warranty claims provided by Ford identified 59,807 claims related to ETB replacements and approximately 50 percent of claims are associated with diagnostic trouble codes (DTC) P2111, “Throttle Body Stuck Open”, and P2112, “Throttle Body Stuck Closed”. Ford described several factors where the ETB motor may fail resulting in DTCs P2111 or P2112 but the failure is not an existing stuck open or closed ETB valve position. According to Ford, the ETB control strategy provides the driver with three FMEM modes that allow varying degrees of vehicle mobility depending on the severity of the fault detected. DTCs associated with stuck open or closed throttle valves are designated the highest failure severity resulting in engine speeds limited to high idle corresponding to the limited limp home mode. Vehicles are not likely to unexpectedly stall as a result of this condition, but drivers may characterize the reduced functionality as a stall, even though their vehicle may still has motive capability. Other FMEM limp modes may result in reduced engine performance but will maintain vehicle speed above 20mph.