The fob may also have to be reprogrammed after the battery has been replaced. Some will retain their code settings while others may not. On VW applications, be careful not to press any buttons while the battery is out of the fob as doing so can erase the fob’s memory.
Push button keyless start systems have a mechanical backup in case the smart fob is defective. There may be an emergency key or a key that pulls out of the fob that can be inserted into a steering column or dash switch. Again, refer to the vehicle service information or owner’s manual for the backup start procedure if the fob is not working.
Additional features that may be part of a push button keyless start system include memory functions, such as changing the seat and mirror positions to suit different drivers, automatic door locking when the vehicle owner exits the vehicle with the smart fob, and the ability to prevent the vehicle owner from accidentally locking the fob inside the vehicle.
STOP FUNCTIONS
The same button that is used to start the engine (or to power up a hybrid-drive system) is also used to turn the engine off. This feature, unfortunately, has resulted in a number of deaths. Here’s what happens:
The motorist pulls their car into an attached garage and exits the vehicle, but leaves the key fob in the car and forgets to turn the engine off. The engine keeps running and carbon monoxide fumes build to dangerous levels inside the garage. Eventually, the fumes seep into the adjacent living quarters and overcome the people inside. Most of the victims to date have been elderly people who owned luxury import cars with relatively quiet engines.
When Toyota was having its “unintended acceleration” issue (which was blamed on interference between the accelerator pedal and incorrect floor mats, sticky accelerator pedals and/or driver error), the operating strategy of the start/stop button was also questioned as a possible cause of several fatalities.
On the Toyota Prius, the Power button must be pressed in and held for three full seconds to kill the engine if the car is being driven. A short tap or pressing the button repeatedly won’t do it. Why? Toyota says the three-second rule is necessary to prevent someone from accidentally bumping the button while driving and killing the engine (which would also kill their power steering assist and create a potentially dangerous situation).
WHEN THINGS GO WRONG
Great as this new technology is, like any other electronic gadgetry, things can and will go wrong. A common complaint is intermittent operation of the push start system. Usually the system works fine, but, sometimes, nothing happens when the start button is pressed.
On 2010 Hyundai Genesis and Coupe models, the cause of an intermittent no-start problem with the push start button usually turns out to be a defective brake pedal switch. The switch is not telling the system that the driver is depressing the brake pedal when the driver tries to start the engine. The fix is to replace the brake pedal switch (P/N 93810-3K000).
On some Volkswagen Passat and other models, the same kind of intermittent operation complaint usually has a different cause. On the VW applications, the problem isn’t the brake pedal switch, but a faulty ignition column immobilizer module.
Other oddities we’ve heard vehicle owners complain about with certain keyless push button start systems is that the smart fob may not always be recognized by the car when the fob is inside the car. The fob may have to be moved around until it can be “seen” by the inside antenna. Others have complained that the fob may be adversely affected by a nearby cell phone (we don’t know if that’s possible or not, but we wouldn’t rule it out entirely when trying to diagnose an intermittent no-start condition).
