Fobs Won't Lock/unlock Car & Start Button Won't Light Up -

pcteam · December 6, 2015

Hi all,

Yesterday my IS220d (2007 model) drove fine. Both key fobs were working great. This morning however none of the fobs are managing to lock or unlock the car. When I press the buttons they flash red, which means the fob batteries are fine. I even replaced one of the batteries around 3 months ago. So I'm sure the fobs aren't the issue.

So moving on, the car was unlocked this morning (I must have forgotten to lock it after getting back last night). Anyway, when I press the down the clutch, the START button doesn't light up green. This has never happened before.

Note, the car Battery was replaced just 2 weeks ago, so I really doubt it's that either.

Does anyone have any idea as to what the problem could be. Very perplexed right now.

Many thanks!

ahmedali44 · December 6, 2015

U could try couple of things first disconnect Battery that might reset ecu or put key in start /stop button keys r not detected or could be radio interference as it's smart keys they use radio waves happened to me on my road about few months ago and now it's fine if it starts move to next Road and try again hope this helps

pcteam · December 6, 2015

U could try couple of things first disconnect battery that might reset ecu or put key in start /stop button keys r not detected or could be radio interference as it's smart keys they use radio waves happened to me on my road about few months ago and now it's fine if it starts move to next Road and try again hope this helps

Thanks for the response. How do I put the key in the start/stop button?

ahmedali44 · December 6, 2015

Just touch on ur start/stop button

ahmedali44 · December 6, 2015

Press clutch touch ur fob on start/stop button green light should come on

ahmedali44 · December 6, 2015

I say I had same problem started like that couldn't lock /unlock open it manually with key started like that @ it started @ look it on next Road everything was fine soon bought it back to my road same thing afterwards it was ok sometimes if there is building work near ur car could interfere with signal also if ur mobile is near it can cause interference

pcteam · December 6, 2015

Press clutch touch ur fob on start/stop button green light should come on

Okay, I just did that, but the green light didn't come on. Tried it a few times. Nothing.

ahmedali44 · December 6, 2015

U tried disconnecting Battery that will reset ecu well I done it it worked just by holding key on button green light came on @ it started sorry don't know what else to suggest maybe someone else can help if u can get codes someone else might know problem where u live

pcteam · December 6, 2015

U tried disconnecting battery that will reset ecu well I done it it worked just by holding key on button green light came on @ it started sorry don't know what else to suggest maybe someone else can help if u can get codes someone else might know problem where u live

Thanks a lot. Okay sure, I will try resetting the ECU by disconnecting the Battery.

pcteam · December 7, 2015

Okay, removed the Battery connection, then waited a few mins, then reconnected. Still nothing.

Someone else told me it could be the alternator or starter. How viable does this sound?

ahmedali44 · December 7, 2015

If u got meter test Battery see what reading it gives it could b a faulty Battery if u got a booster or another car try jumping it, if alternator is faulty it would kill Battery best thing is if u got home recovery call them

jackcramerr · December 8, 2015

try turning the high beams and see if they work and are bright. then with this load measure the Battery voltage.

I have a Battery with me that shows 13v but won't crank. if during crank a Battery falls to or below 11v replace it. it will die soon.

madasahatter · December 10, 2015

I had same problem my red flashing light just stayed lit. I changed fob batteries and tried all the above.

We had a massive downpour through the night, i finished work at 1am every thing was fine. Could not get in the car next morning.

Aventually got in moved the car about 10 feet tried both keys fine. I then parked where i normally park and everything fine untill present.

jackcramerr · December 10, 2015

madashatter I have seen jammers in operation where key fob stops working. Requested to turn off the jammer and it worked. By any chance you live near by a sensitive area?

Verbout · December 10, 2015

Had it happen a couple ot times, once at an airport and once in a pub car park. Put it down to some interference nearby.

is200 Newbie · December 10, 2015

Happenned to me tonight - car opened fine in work before coming home. Got home, parked beside a street lamp on our road (not usual spot) and car doors would not lock - tried for a few mins walking around the car trying to lock it. It eventually did but only single locked itself.

Tried to unlock it and it wouldn't - either by pressing the open button on fob or by touching door handle. Red light flashes on fob when pressed. Took Battery out / cleaned. Tried again and took a further few mins to get it to open. Started car no problem and moved it into my drive. Now opens / double locks no problem every time..

I will get a spare Battery but can lamp posts cause enough interference to disrupt the fob signal? I will try it again tomorrow to see if I can replicate it....

jackcramerr · December 10, 2015

The new LED lamp posta will have SMPS which means noise in the range of KHZ. If that is the case, it should have not pass EMC regulations. I wonder if they meet EU standards or there are some questions to be asked.

Anyone know what frequency the key fob work at ?

madasahatter · December 11, 2015

No LED lamp posts been fitted since no problem what so ever. Its a strange one to say the least.

pcteam · December 11, 2015

Okay, worked out the problem. It was the Battery after all. It was flat. Mechanic said someone probably left light or radio on overnight..

madasahatter · December 11, 2015

Glad you got to the bottom of the problem.

is200 Newbie · December 11, 2015

Bought a new Battery today and replaced the one in the fob. Came home and parked in the same spot ... same thing happenned !

The street light is an old one - gives off a yellowy light. Cant remember it ever being replaced. I live in a small cul de sac though and i can pick up quite a lot of WiFi signals at home from other properties. Maybe an issue with both but i guess as it works fine in the drive (streetlight is at the end of the drive) it may point to interference from the street lighting or both in combination?

madasahatter · December 11, 2015

A while back local tesco cars were filling up and then unable to start. AA lived there turned out to be radio signal from one of mobile phone networks.

Yorkielexus · April 1, 2019

On 12/11/2015 at 6:50 PM, is200 Newbie said:

Bought a new Battery today and replaced the one in the fob. Came home and parked in the same spot ... same thing happenned !

The street light is an old one - gives off a yellowy light. Cant remember it ever being replaced. I live in a small cul de sac though and i can pick up quite a lot of WiFi signals at home from other properties. Maybe an issue with both but i guess as it works fine in the drive (streetlight is at the end of the drive) it may point to interference from the street lighting or both in combination?

Hi I know this an old thread, I have a CT200H 2013 and it won't start. I have tried jumping it and the key fob batteries are all new. My boot also won't open so I can't get to the Battery.

Has anyone any ideas please?

Surebet · April 2, 2019

Hi Yorkielexus

Don't know if the CT200H key fob has the metal key enclosed in it like my IS250, if so take key out and under the boot/hatchback lid where the reversing camera is situated , you will see metal keyhole. the metal key from key fob should then unlock your boot. Hopefully this will work, I know this worked with mine when the boot interior light was left on a couple of weeks ago resulting in a flat battery . Good luck.

Bagio · November 9, 2020

HI Yorkielexus et al, Another reason boot might not open is that it is disabled, this will stop you from opening it from the fob button and manually with boot button (outside vehicle) and it won't open via the inside vehicle boot button either. This is an intentional feature (valet mode). stopping people steal things from your boot when you give someone your fob to park your car (note you should only be giving your fob over and not your key/s). Ok how to enable/disable (valet mode). inside your glove box there is a button (in my Lexus it is at the front on the right (RHD car))to disable your boot buttons, the idea is you deactivate then lock your glovebox with your manual key, hand over your fob to valet to park your car knowing your glovebox and boot are locked and secure. Hope this helps 😄

P.S. I am also experiencing key not detected issues hence why I was reading this thread. I will do some investigations as per some comments I have read.