I bought a used 2011 Sienna XLE about two months ago, equipped with the “Smart-Key,” a **key-less** electronic key. (I like the Sienna. I don’t like the electronic key.)

I thought of **one** way to protect myself against the failure of the 2032 battery (locking me out of the car):

· I bought a pair of 2032 batteries.
· Among my tools, I located a screwdriver of the proper size to pry open the key fob in order to change the battery.
· I put the screwdriver and the batteries in the glove box.

If the electronic key’s battery dies at the worst time, locking me out of the car, I can get into the car -- using the mechanical key that is encased in the key fob. Once I’m in the car, I can replace the key fob’s battery.
Please give me your reactions to this plan. If you have a better plan or if you have comments (positive or negative) about the “Smart-Key” please email me or post them.

Your smart key isn't like mine then? Mine has a small button on the side that pops out an anti-theft key which will get me into the van even if the batteries are dead.

 

To rworne.

My mistake. My original post wasn't clear.

You are right, of course... the built-in key will allow entry into the van. But if the battery is dead, I'm **assuming** that the car can't be started. (Please reread my revised post.)

But you have brought out an important question: If the key fob battery is **dead**, but the key fob **and the driver** are in the car, can the car be started and operated as usual? If it is possible to start the car under such conditions?

Thank you for your reply and please let me know about this.

 

It is easy to try. Just take out the battery and check if you can start your van.

 

It is easy to try. Just take out the battery and check if you can start your van.

Thank you, Romualds, for your suggestion. Here's my plan:
o Get a brand-new battery for the keyfob
o Open the keyfob, remove old battery, whether it's working or not.
o Verify that the mechanical key opens the van door properly, as it should
o Try to start the van according to pp 717, 718 in 2011 Sienna Owners Manual

If all goes well, install the new battery in the keyfob. By following this sequence, I have minimized the number of times that the fob will be pried open AND I have verified the instructions in the manual. In my opinion, the manual is vague -- there is no strong assurance that the process they describe to start the van will **absolutely** work!

 

I guess you could also keep a spare battery in the glove box in case of emergency, however how would it keep freshly charged ? Keep buying a new one every couple years , sounds wasteful .

 

Keeping a Smart Key near a cell phone will drain the battery faster as the key will respond to the cell phone's transmissions. Toyota recommends at least one foot of separation to reduce this. The van will start with a dead Smart Key battery if you hold the key against the start button as you press the start button. From the Owner's Manual page 49.

Electronic key battery depletion

- The standard battery life is 1 to 2 years.
- If the battery becomes low, an alarm will sound in the cabin when the engine stops.
- As the electronic key always transmits radio waves, the battery will become depleted even if the electronic key is not used. The following symptoms indicate that the electronic key battery may be depleted. Replace the battery when necessary.

• The smart key system or the wireless remote control does not operate.
• The detection area becomes smaller.
• The LED indicator on the key surface does not turn on.

- To avoid serious deterioration, do not leave the electronic key within 3 ft. (1 m) of the following electrical appliances that produce a magnetic field.

• TVs
• Personal computers
• Recharging cellular phones or cordless phones
• Cellular phones, cordless phones and battery chargers
• Glass top ranges
• Table lamps

 

From the Repair Manual. I think I read this elsewhere, but this is what I found first. Note that the system will generate a warning telling you you have a low key battery before it dies. The Owner's manual (page 643) is particularly weak on this subject.

With a low key battery, the master warning light will flash and the buzzer in the combination meter will sound. The Accessory Meter Assembly will display "Low Smart Key Battery" or "Low Key Battery."

Note: If the key remains within the exterior actuation area of any door electrical key oscillator, the system maintains periodic communication with key. Therefore, if the vehicle remains parked in that state for a long time, the key battery and the vehicle battery could be drained.

WHEN KEY BATTERY IS LOW

(a) To operate the push-button start function when the key battery is low, hold the key close to the engine switch with the brake pedal depressed.

(b) The power management control ECU transmits a key verification request signal to the certification ECU (smart key ECU assembly) when it receives the stop light switch signal.

(c) The certification ECU (smart key ECU assembly) does not receive an ID code response from the entry door control receiver, so it actuates the transponder key amplifier built into the engine switch.

(d) The transponder key amplifier outputs an engine immobiliser radio wave to the key.

(e) The key receives the radio wave, and returns a radio wave response to the transponder key amplifier.

(f) The transponder key amplifier combines the key ID codes with the radio wave response, and transmits it to the certification ECU (smart key ECU assembly).

(g) The certification ECU (smart key ECU assembly) judges and verifies the ID code, and transmits a key verification OK signal to the power management control ECU. The buzzer in the combination meter sounds at the same time.

(h) After the buzzer sounds, if the engine switch is pressed within 5 seconds with the brake pedal not depressed, the power source mode changes to on (ACC) or on (IG), the same as in the normal condition.

 

You can still start the engine even if the battery in the electronic key is dead. After entering the vehicle using the emergency metal key stored inside the electronic key, simply touch the electronic key to the start button per the procedure on page 720 of the owners manual. This process will get you around until you can replace the battery.

 

I know this is an old post, but the inaccuracies were bugging me, so for the sake of correctness, here's what I know.
The vehicle can be opened and started even when the key's battery is dead- To open the car, use the mechanical key. To start it, (as IdahoLuke mentioned) touch the fob to the ignition button and then press the button.

There is also no need for a separate screwdriver to open the fob for battery replacement (despite what the manual suggests). Remove the mechanical key from the fob and look at the tip. On both our 2010 RAV4 (with a smart key) and our 2015 Sienna, the tip of the mechanical key is the exact right size to fit in the pry-gap. Just put it in the gap, give it a little twist and the fob will pop right open. No need for a separate screw driver. At most, you'd just need an extra battery in the glove box.