[arunphilip]

Changing the Key Battery
I have an August 2013 EcoSport with keyless entry and push-button start. About 10 days ago, I received this warning on my Sync screen:

Key Battery Low
Replace Battery

It was quite obvious and helpful to see this warning message - it meant that the battery in my key was failing. Once that battery went down fully - it would mean I'd have to unlock the car using the key (the key is hidden inside the key fob itself) and would have to hold the key where the ignition slot is usually present to use push-button start (more details below).

As I'm not at home, I don't have immediate access to my spare key. After putting off the battery replacement for these 10 days, I decided to finally make the change.

The user's manual gives quite clear instructions on how to replace the battery, and I thought I'd supplement it with a few photos.

1. Accessing the Physical Key

The physical key is just one step away - pressing two buttons will pop open the Ford logo on the rear of the key fob, and lets you access the key. In case your key battery is completely dead, you can use this key to open your car, since the driver's side door has a key slot even for the push-button start enabled vehicles.

However, to replace the key battery, you don't need to actually use this key, you just need to remove it from the key fob.

With the logo off and the key removed, you can see some details. The key fob (and by extension, I assume the keyless entry module) is manufactured by Continental. Here's Continental's home page for keyless entry systems.

The key fob itself carries Ford part number CN15-15K601-AB.

2. Opening the Key Fob into Two Halves

For these two steps, gently use a flat-headed screwdriver to avoid damaging any plastic. With these two steps complete, a latch should be undone, which will allow you to use your nail to pry apart the two halves of the key fob around the center.

Once the key is in 2 halves, you'll notice that one half has a circuit board. This contains the radio frequency (RF) circuitry, programmable transponder, etc.

You don't need to do anything to this while replacing the battery, so you can safely set it aside.

The other half carries just the battery:

The battery used is a 3V coin cell battery, called the CR2032 model. The battery is installed with the positive side facing the plastic of the key, and the negative facing upwards (i.e. you can see the negative in the above picture).

3. Replace the Battery

You can pop the old battery out with careful pressure from a flat-headed screwdriver, and replace it with a new battery.

Then its just a matter of closing up the remote in much the same way as you opened it.

Notes and Miscellaneous Points

• CR2032 batteries can be bought either online, from shops that deal with electronics, or even large supermarkets. Popular brands for CR3032 are Panasonic and Maxell (not Maxwell). Unfortunately, fake batteries are very common, so ensure that you purchase it from a trusted source in your area.
• Out of curiosity, I checked the voltages for the old and new batteries using a multimeter. The old battery gave a voltage of 2.977 V (DC) and the new one 3.438 V (DC). Generally, the cut-off voltage for CR2032 is defined as 2V. This makes me wonder whether Ford have programmed in a larger margin of safety in terms of making the warning appear earlier (to cater to lazy geese like me).
• Old Battery Voltage:
• New Battery Voltage:
• Ignore the minus sign in the above screenshots, I had my test leads reversed.

What if your car has keyless entry/push-button start and the battery is totally dead?
Car manufacturers have designed their systems for this eventuality.

To get into the car, you can unlock the driver's door (which does have a keyhole) using a physical key. This physical key is contained within the key fob itself, and accessing the physical key is detailed below.

To then start your car, you have to hold the key fob next to the steering column where there's a circular mark (this is where the ignition slot is present in a normal car).

How this part works is pretty cool. By default, the battery in the key fob drives an RF transmitter that announces its presence to the car, allowing the touch sensor to unlock the car, and the car to detect the key fob's presence in the car when the push-button start is pressed.

On the other hand, when the key fob's battery is drained, the key fob has a backup passive mode. The steering column has a transmitter that sends a signal, and this radio signal is good enough to power the transponder chip in the key fob to identify itself, even when the key fob itself has no power. This is quite similar to how RFID systems work.

This way, you can still use your car even with a fully dead battery in the key fob.

[penpavan]

Originally Posted by arunphilip

Changing the Key Battery

What if your car has keyless entry/push-button start and the battery is totally dead?

Thanks Arun for the excellent step by step guide. I have a June 2013 Ecoboost and was warned about the draining battery about a month and half ago. Amazing consistency as to how the battery has performed in the same period.

I was not aware of what to do when the battery goes completely dead. Thanks again for the enlightening post.

BTW, I had taken help of this video.

https://www.youtube.com/watch?v=OvF2Ie9rCg4

[ecosport rules]

Originally Posted by arunphilip

1)CR2032 batteries can be bought either online, from shops that deal with electronics, or even large supermarkets. Popular brands for CR3032 are Panasonic and Maxell (not Maxwell). Unfortunately, fake batteries are very common, so ensure that you purchase it from a trusted source in your area.

2) The old battery gave a voltage of 2.977 V (DC) and the new one 3.438 V (DC). Generally, the cut-off voltage for CR2032 is defined as 2V. This makes me wonder whether Ford have programmed in a larger margin of safety in terms of making the warning appear earlier (to cater to lazy geese like me).

3)On the other hand, when the key fob's battery is drained, the key fob has a backup passive mode. The steering column has a transmitter that sends a signal, and this radio signal is good enough to power the transponder chip in the key fob to identify itself, even when the key fob itself has no power. This is quite similar to how RFID systems work.

This way, you can still use your car even with a fully dead battery in the key fob.

Thanks for the detailed description.
Few observations and one question from my side:

1) Ford ASS is selling the CR2032 battery for INR 750 I am not joking.
I was in splits when the parts manger told me the price, got it for INR 70 on amazon

2)True that about the larger margin by Ford.
I Deliberately didn't change the battery in mine to check the remaining life after the" low battery "warning
It has been 3 months and it still works well every day

3) Will the key fob passive back up mode work even if the battery is removed or will it work only on low battery

[Thad E Ginathom]

Originally Posted by ecosport rules

1) Ford ASS is selling the CR2032 battery for INR 750 I am not joking.
I was in splits when the parts manger told me the price, got it for INR 70 on amazon

You could have got one from your local-street gadget/electrics shop: it is the battery used on PC motherboards. Prices for CR2032 do seem to vary widely though. The obvious fakes are very cheap; the hopefully-genuinely branded ones are surprisingly expensive.

[GTO]

Thanks for sharing, Arunphilip! Moving your post to an independent thread so that other EcoSport owners don't miss it.

[vaasscit]

Originally Posted by ecosport rules

got it for INR 70 on amazon

MRP of CR2032 is INR 40. Got it confirmed from the Manufacturer. Posting it for the benefit of everyone.

[JoeTheWanderer]

Originally Posted by ecosport rules

1) Ford ASS is selling the CR2032 battery for INR 750

Just got my EcoSport keys' battery changed (the keyless ignition type).

Both the keyfobs' battery had gone kaput about 2 months ago. I was visiting the Royal Enfield service center, so thought I'd get the batteries changed at Ford.

I was in and out in about 15 minutes having paid a total of Rs. 366.

They gave the old batteries back as well. Here's the part number.



This was at Mody Ford Bowenpally (near MMR Gardens).

I did look at this DIY, but couldn't pry the keofob apart - maybe I was just too scared.

[n_ramesh99]

Originally Posted by arunphilip

Changing the Key Battery


What if your car has keyless entry/push-button start and the battery is totally dead?
Car manufacturers have designed their systems for this eventuality.

<snip>

This way, you can still use your car even with a fully dead battery in the key fob.

This post has been useful almost 6 years after it was posted!

I have a problem of excessive draining of cell. The low voltage warning pops up within a few weeks of replacing with a new cell. I was originally under impression that there was no way to start the car if the battery is completely drained. I was told the same when I took the delivery of the car. After reading this post, I was relieved that I did not have to change the keyfob immidietely. I tried the method posted and I see that it works.

[Dramitn]

Just a quick update to the thread
For the 2017 onwards facelifted ecosport the battery is PANASONIC CR2450

Pasting the link from Amazon

Panasonic CR-2450 Lithium Coin Battery 3v - Pack of 5 Provide Long Lasting Power in a Variety of Devices,from keyless-Entry fobs to Toys
https://amzn.eu/d/4aTn1H5

[Samfromindia]

Originally Posted by JoeTheWanderer

Just got my EcoSport keys' battery changed (the keyless ignition type).

Both the keyfobs' battery had gone kaput about 2 months ago. I was visiting the Royal Enfield service center, so thought I'd get the batteries changed at Ford.

I was in and out in about 15 minutes having paid a total of Rs. 366.

They gave the old batteries back as well. Here's the part number.
Attachment 2129270


This was at Mody Ford Bowenpally (near MMR Gardens).

I did look at this DIY, but couldn't pry the keofob apart - maybe I was just too scared.

Pack of 5 Duracell CR2032 goes for 136.

https://amzn.eu/d/1op00rz

This is perhaps one of the most popular cell battery along with LR44 used in devices from watches to handheld video games. And not to forget, computer motherboard uses this same battery for BIOS.

[Dramitn]

Originally Posted by Dramitn

Just a quick update to the thread
For the 2017 onwards facelifted ecosport the battery is PANASONIC CR2450

Pasting the link from Amazon

Panasonic CR-2450 Lithium Coin Battery 3v - Pack of 5 Provide Long Lasting Power in a Variety of Devices,from keyless-Entry fobs to Toys
https://amzn.eu/d/4aTn1H5

in the facelift version the key is slightly different

posting the steps to change the battery in the ford ecosport 2018 facelifted version

the battery for the key is the panasonic CR2450

remove the key from the key fob

there is a notch on the top portion depicted in the second picture.

pull it apart

another notch next to the clip holding the battery in place, insert a pen to tease the battery out

replace battery and reassemble the key fob and you are done.