Background #
As delivered the MGF comes with 2 keys and 2 fobs. If you only have one fob, this could be problematic in managing the engine immobilizer and the alarm system. So, if you don’t have 2 fobs then an MGF key fob replacement is likely a good idea.
For UK spec vehicles, the alarm and engine immobilizer system are a little more aggressive, which makes the key fob even more critical. The Japanese specification cars were a bit more driver friendly for this aspect.
All MGFs use the Lucas 5AS system and the fob(s) are square (square-ish anyway) in shape. The fob has just 2 buttons, lock and unlock.
Which Fob? 433Mhz or 315Mhz #
It’s important to know that there are two different frequencies in use for the Lucas 5AS system. You need to make sure that you get the right replacement fob. The 433Mhz versions are most common. These are what the UK and EU markets use. The 315Mhz version is for Japan and some other export markets. So, you need to be sure which you have. If you know the history of your car this may not be a factor.
There is no easy visual way to know this looking at the outside of the fob. However, if you open up the fob, there is a transponder on the circuit board on the same side as the battery. Its shown in the pictures at the bottom left of the circuit board (click on images for a larger view). If you look at this you will find printed either 1207 for a 433Mhz unit or 1239 for a 315Mhz unit. It is printed on the top of the round silver transponder.
Once you know which fob type you need, you’re ready for an MGF key fob replacement.
Programming The Fob To Your MGF #
If you buy a fob from somewhere, it will not just work with your car. The fob must be programmed (or paired/coded) to work with your MGF. The Lucas 5AS ECU has to “know” the fob(s) that are valid for the car. So how do you get this accomplished? There are potentially other options but these are two that I know about.
Remote Key Ltd Service With DIY Programming Device #
Before I knew that a PSCAN unit could be used for programming fobs, I was looking for a solution to get a 2nd fob for my 1997 MGF, Japanese export model. I found the company Remote Key online who offer not only a new fob but also an option to provide it with a DIY programming device. This sounded like a good idea and, at the time, knowing nothing about all this, they were extremely helpful in verifying I needed the 315Mhz type unit. I had the new fob and programming device delivered to a UK address while visiting family.
If you order the with the DIY programming device, there is a £30 deposit. You receive a refund on return of the programming device. In the UK the postage to return the programming device is prepaid. Outside the UK you’ll have to pay to post it back. This is truly as simple to use as the website notes. See the video I took of the process – not overly exciting as it just works!
If you don’t already have/know the Emergency Key Access (EKA) code, Remote Key will send you and email with it when they receive the programming device back.
Using a PSCAN Device #
Since using the Remote Key Ltd service, I discovered that a PSCAN unit can also allow you to program a fob. The PSCAN unit does lots of things beyond fob reprogramming. In hindsight, given I’m in the USA and have to self-support all issues with my MGF, I should have just bought the PSCAN unit and a fob. Live and learn. Still, the Remote Key solution is so simple it may appeal because it truly is so simple.
For reference the PSCAN device is described as: A PC-based tool to read error codes and live data parameters from engine, ABS, airbag, alarm and body controller ECUs fitted to Rover, MG and Landrover cars. Designed to give dealer level access (approaching that of T4) for supported vehicles. I will add a separate article about the PSCAN at a later date. I have purchased one now, and find it quite easy to use and truly helpful getting precise information on any error codes and other information from the Engine Management System (EMS) and other onboard systems.
Since I didn’t need to add another fob, I found a very good video “How To” on YouTube by Beards and Bangers. It shows you how to program a fob for an MGF. Better to watch the process than write it out. As you can see, it is quite easy and the software guides you through the process. This page on the PSCAN website has a screen image which shows the overview instructions the software provides to assist, as shown in the video.
Other Devices – PSCAN Alternatives #
If you have an appropriate T4 device you can also use this to program fobs for an MGF key fob replacement.
Other Materials #
I’ve built this website and spent time on the knowledge base to bring together a lot of information I have collected from around the internet. The intent is making it easy to find rather than having to know about and have skills with search engine query terms to get what you were looking for. Please make use of the knowledge base.
