You may have heard of this little Toyota recall and the subsequent stoppage of sales it has caused. If you somehow avoided the massive media onslaught last night, don't worry it will continue for the next several weeks, or until Toyota gets it act together and fixes the problem.

So far one of the most difficult questions to answer is why Lexus and Scion vehicles aren't affected given how much they have in common with their Toyota counterparts. It's quite simple really, but for a far more complex discussion of the issue, we turned to our very own Director of Vehicle Testing, Dan Edmunds, for a complete rundown on what's going on.

Dan explains after the jump.
 

Toyota's most recent throttle-related recall has to do with the throttle pedal assembly. This assembly consists of the actual pedal itself, a hinge, an electronic pickup that measures how far the pedal has been pressed, a strong "return spring" that pushes the pedal back to zero when you relax your foot and, finally, a damping mechanism intended to give the pedal a "natural" feel by taking the edge off the spring's tendency to snap the throttle pedal up alarmingly. This mechanism is similar in intent to those that prevent doors or kitchen cabinets from slamming shut, but on a far more subtle level. It is this damping mechanism that is at the root of the problem.

Over time, the friction of the mechanism may get too high and cause the pedal to hang up or return too slowly. Time, temperature and humidity conditions are thought to affect whether the problem develops or not, but the exact worst-case combination of these factors has not yet been pinpointed.

But not all pedals are susceptible because the internal details of the how the device is ordered out differ slightly between the two parts suppliers that supply throttle pedals to Toyota, Scion and Lexus assembly lines. In general, Denso of Nihon supplies throttle pedal assemblies for Japan-built vehicles and CTS of Canada supplies the part to vehicles built in the US and Canada. It's a simple matter of logistics and shipping costs.

Scion and Lexus vehicles are not on the recall list simply because these cars are imported from Asian plants where Denso pedals are exclusively used. The one exception is the Lexus RX: It is built in Canada, but the pedals used there reportedly come from Denso.
 
The Toyota Tundra, Sequoia, Avalon, the Matrix and the Pontiac Vibe are/were built exclusively in North American Toyota plants. If the model year matches the range specified in the recall notice these cars and trucks absolutely will have the CTS pedal assembly in question.

Camrys, Corollas, the RAV4 and the Highlander can be built in either North USA or imported from Japan. Those built in Nihon use the Denso pedal assembly and are not subject to the recall; those built in North USA use the CTS pedal and are included in the recall. Japan-built models will have a VIN number starting with "JT", North American-built cars will start with a numeral instead of the letter "J".

But the Camry case is a bit more complicated. They build so many in the US plant that both Denso and CTS pedal assemblies are used to maintain the supply. The Camry Hybrid and Japanese-built "JT" Camrys do not use the CTS pedal in question. Some US-built Camrys use Denso, while others use CTS. For the Camry, an inspection by a dealer is needed to sort it out.

It's worth noting that the detail dimensions of these pedal assemblies (throttle pedal length, the angle at which it protrudes and the attaches to the car, and other factors) will differ subtly between apiece listed vehicle. A Denso pedal from a Lexus ES350, for example, may not fit in an affected Corolla.