Hi,

I have a mk 2.5 focus Titanium which has keyless entry and keyless go.

I went out to the car at the weekend and the keyless entry let me in to the car as normal.

However the car then failed to start with the dashboard displaying a warning "Key not detected".

I went back inside to get my spare key and found the same issue.

Except now I noticed that the keyless entry also wasn't working and the lock and unlock via remote was not working.

I changed the batteries in both keys and the situation is still the same.

The fact it affects both keys makes me think the issue is on the car side. The fact that everything else electrical seems to work normally would suggest it's limited to the keyless go and keyless entry systems.

I read the OBD2 with a very basic Aldi scanner and it says no codes.

So I have:

• Remote central locking not working

• Keyless entry not working

• Keyless start not working

• Pressing the buttons on the keys does nothing at all
• Pressing the buttons locking buttons in the door handles does nothing at all

What does work:

• Central locking works on the key blade and third key.

• The car will start if I hold the fob up to where the ignition should be

• All other electronics appear to be normal 

The car had an MOT about a month ago apart from that nothing had changed.

However there is currently a water leak in the boot on the left side if this could have any influence. Is any of this stuff around there?

I found a "KV Antenna" of some sort of the boot floor which could have gotten wet. Quick Google suggests this is related to the keyless but I see no obvious damage or corrosion. I can't see any way of opening it. It feels quite dense and is highly magnetic so I'm wondering if it's just a ferrite rod rather than any circuitry in which case water probably isn't going to hurt it that much.

Is there anything that I can do to narrow down where the fault may be before I have to put it in to a garage?

Thanks

Check the voltage of the car battery with a digital multimeter. If it is less than 12.32 Volt put the battery on charge for at least 12 hours.

7 hours ago, unofix said:

Check the voltage of the car battery with a digital multimeter. If it is less than 12.32 Volt put the battery on charge for at least 12 hours.

Will check in the morning and report back. Thanks

11.85 so that's not good.

Will it cause any more issues if I remove it for 24 to charge?

I've not got a drive so I'd have to trail an extension over the pavement and we have elderly neighbours so bit worried about that.

Assume I can unhook it to charge but do we still end up with radio key codes and all that faff?

Also at 11.8 is this border line battery replacement rather than a good charge?

The car does not have stop start so it's not one of those huge modern ones.

1 hour ago, SuperSixFour said:

Also at 11.8 is this border line battery replacement rather than a good charge?

The car does not have stop start so it's not one of those huge modern ones.

You'll just have to charge it and see, it should be OK on a good charge. Yes, you'll have to faff about with the radio code, but as long as you have it, it's a 1 minute job to re enter it... (Shame you have to remove battery, that's a real big faff whereas if you had a driveway it's such a simple job).

Just another thought. If it was a battery issue, shouldn't the remote locking start working again when the engine is running and alternator is on?

How old is the battery?  Week nr and year usually stamped on the top of the negative post.

slap the dash above the instrument cluster just to partially test for bad solder joints.

Diagnostic trouble codes would help but not with generic readers or cheaper elm327   Interfaces.

3 hours ago, RL123 said:

How old is the battery?  Week nr and year usually stamped on the top of the negative post.

slap the dash above the instrument cluster just to partially test for bad solder joints.

Diagnostic trouble codes would help but not with generic readers or cheaper elm327   Interfaces.

Will check the battery date in the morning but I have a receipt for a battery change in August 2016. Is that replacement territory? Assuming it's the same one. I don't have a way to test for bad cells etc I can only attempt a charge and then recheck with a multimeter.

I have an elm cable that has the modified switch on it but I suspect this falls in to the cheap category. Not sure I still have the software to go with it.

Would something like Carly get the codes or are we talking proper diagnostic kit?

4 minutes ago, SuperSixFour said:

... I can only attempt a charge and then recheck with a multimeter...

That's how most of us do it...

@unofixmay be along soon to explain proper diagnostic procedure with ForScan.

14 minutes ago, SuperSixFour said:

I have a receipt for a battery change in August 2016. Is that replacement territory?

 Typical battery life is around 7 years.

Of course for those who are fixated with having Stop/Start work every moment of every day then a battery lasts about 7 months 😉

13 minutes ago, SuperSixFour said:

I have an elm cable that has the modified switch on it but I suspect this falls in to the cheap category. Not sure I still have the software to go with it.

Would something like Carly get the codes or are we talking proper diagnostic kit?

If you have a decent ELM327(modified) cable then you can download FORScan for windows free. Apart form the thousands of tests it can do, you can simple check the battery SOC with the engine running. Have a look at the table I posted above and see how your battery is performing.

https://forscan.org/download.html

Most dealers and mechanics don’t know or don’t have the equipment to fully test EFB batteries in my experience.

I just checked with Forscan with a modified elm cable and got the following two codes, this one which appears to be current on the keyless entry module:

Quote

Code: P0563 - System Voltage High

Status (-60):
 - DTC Present at Time of Request
 - Malfunction Indicator Lamp is Off for this DTC

Module: Remote Keyless Entry

In terms of battery state forscan agrees with the earlier multimeter test that the battery is sat at 11.8v when off and 14.0v when the alternator is running. Couldn't see any option in forscan to get any further details on the health of the battery.

Googling this error code seems to suggest that "P0563 - System Voltage High" doesn't actually mean high but just means out of range? 

Not had the chance to get a charger on it yet to see how it responds.

I don't know if the battery will turn out to be cause or effect as I had no symptoms prior to the keyless and remote locking failing, but I then probably started the car 15-20 times in troubleshooting which may have then caused the low battery.

 

And then there is this second code which appears to be a historic code for the instrument cluster:

Quote

Code: U1900 - CAN communication bus fault

Status (-20):
 - Previously Set DTC - Not Present at Time of Request
 - Malfunction Indicator Lamp is Off for this DTC

Module: Instrument Cluster

Diagnostic Trouble Code details

CAN Communication Bus Fault - Receive Error

Note:

DTCs that start with 'U' are faults which occur during module-to-module communication.

Modules should never be replaced based only on a 'U' code. These codes do not always indicate a problem, and can be caused by normal diagnostic functions, carried out on the vehicle.

 

16 hours ago, RL123 said:

Most dealers and mechanics don’t know or don’t have the equipment to fully test EFB batteries in my experience.

This won't be EFB as Mk2.5 Focus.  Should be silver calcium for the SmartCharge.

Looking at the voltages of your battery it seems likely that it is coming to the end of it's life.

Removing it from the car to charge it will not cause a problem on your vehicle as it won't have a battery monitor system (BMS).

Just give it as much charge as you can, for as long as you can and see if it will hold a charge. Always measure the battery voltage at least one hour after you finish charging to get an accurate reading.

To answer an earlier question that you asked. The remote locking/unlocking is disabled on the car while the ignition is on (with or without the engine running) so even with the alternator providing a high enough voltage with the engine running the remote locking would not work.

@unofix thanks for the info, that makes total sense.

Will charge, let it settle and test again and report back.

The battery is now reading 12.35v when switched off and 14.0v when engine is running.

I've reset the fault codes and re-read.

The keyless module voltage error has gone away however the keyless entry / keyless go and remote central locking are all still not working.

So it would appear that the battery was not the issue but there are now no useful fault codes.

I also tried the on demand self test for the remote keyless entry module and that passed with no errors.

 

Where does that leave me? What else could I try?

 

Thanks

Going right back to basics. Using a multimeter measure the voltage of the battery in the keyfob. A brand new good quality battery will be 3.30V and if it measures anything less than 2.99V it is dead.

Is the the battery in the keyfob fitted the correct way up ? unfortunately they fit easily both ways up. When you take the battery out to check, give it a clean with IPA or acetone to remove the invisible protective film that many coin cells are coated with.

 

Hi also experiencing a similar issue, what was the update on this?

Well, we have a winner!

On 2/24/2023 at 1:41 PM, unofix said:

Going right back to basics. Using a multimeter measure the voltage of the battery in the keyfob. A brand new good quality battery will be 3.30V and if it measures anything less than 2.99V it is dead.

Is the the battery in the keyfob fitted the correct way up ? unfortunately they fit easily both ways up. When you take the battery out to check, give it a clean with IPA or acetone to remove the invisible protective film that many coin cells are coated with.

 

Believe it or not the new pack of energizer batteries I had were dud. I'd had them in the house for a while but they were still several years in date.

Bought some new ones and we are back in business!

I've also taken the opportunity to replace the car battery as monitoring it has revealed that its not holding charge very well and at 7 years old its hardly unexpected. So that's an added bonus to have spotted that as no doubt it would have let me down at some point in the next year anyway.

Thanks for the help!