(October 4, 2012) Automotive News is reporting today that Toyota and Subaru are seeking a solution to rough idle and stalling conditions on their new sporty coupes. The automakers say that the problems on initial batches of the Subaru BRZ coupe and its Scion FR-S twin is being caused by a software mapping glitch.

Toyota and Subaru, a unit of Fuji Heavy Industries, developed the sporty cars jointly. And except for some badging and front fascia differences, they are basically clones.

Toyota and Subaru said that there is no mechanical defect. But some owners of the coupes disagree, saying the suggested fix hasn’t kept the problem from recurring.

Toyota spokesman Brian Lyons told Automotive News that when the engine control unit (ECU) is installed, it adapts to the car's powertrain and owner's driving patterns, a process known as adaptive learning. Within 100 miles, those settings are basically frozen in the ECU.

With the Toyota and Subaru coupes, some of the software coding that allows the ECU to establish a "handshake" with the engine is in error. The ECU monitors certain driving conditions, and when the engine is found to be out of tolerance, the software picks up an anomaly.

Source: Automotive News