Keys

[Bosley]

Hi,

I picked up a MK3 1.8 a few weeks ago, it has 2 keys with dead batteries and I have been using the keys in the lock old fashioned style, now I’m quite happy with this, will doing this create a long term problem? as I am paranoid about car alarms, I have ordered 2 new batteries, if and when I fit them will the car recognize the keys with new batteries without setting anything off , or should I just stick to what I am doing now?

Any advice appreciated.

Cheers

Boz

[andy1964]

Should be OK with the new batteries - I’ve swapped the batteries in mine twice since I got the car, without any problems.

If you use the key in the lock, can you still deadlock the lock - as you can with the keyfob, by pressing the “lock” button twice?  This is a good security feature.

Also the keyfob (on mine) has a button to enable you to disable the interior alarm sensor after locking the car - this sensor can, in a few circumstances, cause false alarms e.g. a metal garage door being opened & closed which happens to mine if I reverse into the garage but not if I drive in forwards.

Also, using the keyfob to lock & unlock (rather than the key itself) will result in no wear & tear on the door lock barrel of course.

[Drumtochty]

Warning it is not unusual to get “new” batteries that have been around for a time and will not work the fob as the voltage is down, happened to me last month. A fresh set of “new” batteries sorted it.

All things being equal new batteries will get the fob to work without any further issues.

The instructions to change the batteries is in the owners manual.

[rhino666]

Changing batteries is not going to cause issue.

If you consider that removal of the remote from the range of the car is the equivalent of changing of the batteries.

worse case scenario, reprogramming the remote side is reasonably straightforward - sticky post on the subject somewhere but get back if there is a problem.    

[Mudster]

When I bought my NC, one fob had a flat battery and the other almost flat (no range on the fob and didn’t always work). 

The completely flat one had a broken tang on the key holder section and had been glued together. Had to get a replacement case from eBay and transfer electronics over from old to new case. I reckon it had been flat some time and just worked straight away.

[delboymcc]

I bought 2 new key cases from amazon, paid to have them cut, inserted the electonics. They opened the doors but the car showed a red key on the dash (immobilizer I assume) and will not start. Any ideas.

[Roadster_Robbie]

You’re not the first…

Problems with Key after fitting new case

Hi all, I have a Mk3 NC 2008 car. It came with two keys. Both worked fine but one had a damaged case. I bought a new plastic case and transferred the Key, PCB and Battery. Initially nothing worked. After repairing the key it will now lock and unlock the car. But it won’t start the engine. Any ideas. Pairing Method used Remove key from ignition switch. Close all doors. Open driver’s door. Carry out the following procedure within 24 seconds: Turn ignition switch ON and back to LOCK pos…

[Mudster]

Did you swap the immobiliser chip from the old key case to the new case. It’s a small grey oblong glued into the case and you need to ensure it isn’t damaged when swapping over.

I used some side cutters on the plastic case and carefully trimmed back with a Stanley knife to get the chip out. It completely destroys the old key case.

[delboymcc]

Hi. I cant find anything in the buttons end. Is it in the key hinge end that doesnt come apart and is that why you have to destroy the case to get it out?

[Roadster_Robbie]

Does this help?

Immobiliser kicks in after changing key fob body

Here is a pic of a blank key and its plastic housing without an immobiliser chip. I put a scrap of paper in the slot where it would live to make this easier to see. The screw holding it all together is hidden under the Mazda badge. I needed the other half where the circuit board lives simply because the button sheet had lost its integrity. [20200615_230353_c]

[delboymcc]

Hi. Thanks for that. As it was the plastic catch that keeps the electronic part to the key part that had been broke by a previous owner, I did`nt need to break out the chip I just exchanged the other half of the key holder, so no damage to the chip and key all in one piece.Brilliant !

[Mudster]

Aah, fair enough.

My case had the broken clip and somebody had superglued it all back together until the battery ran out. Just thought I would change the battery and ended up having to destroy the whole casing.