Problem with Rover / Lucas 3AS immobiliser

[MargoC]

Hi!

I bought my Cortez nearly 2 years ago and previous owner had already bought new one-button-key-fob for car, but it still didn’t work every time. So, last year I changed master central door lock mechanism and it worked better for some time, but still not always.

This winter, on last drive, that Lucas / Rover 3AS immobiliser black box itself started doing some noise and gave me quite thrill when I needed lock the car and start it again. Las time it functioned, when I accidently locked the car after that drive.

At the end of April, I had to take the time to deal with this issue, as Cortez was on studded tires and MOT was also at the end of May. Long story short – I didn’t get central door lock working and immobiliser off, so no chance to get engine running and prepare Cortez for summer.

I searched internet, Haynes manual and even took my 3AS apart and found, that for unknown reasons several “legs” on main Motorola chip were black, kind a burnt. I consulted with electrician and he said, I could try and clean the legs and if any of them were broken, then these could be re soldered. After cleaning, all legs were intact, but as much as I could see, there were some damages to tracks and small connection parts too. So, unfortunately cleaning didn’t help either and most likely my 3AS is toasted.

As I live in Estonia and Rovers from 90-s aren’t very common, then even local Rover enthusiasts and workshop don’t know anything about 3AS systems. They just suggest changing it to more modern one.

Doing the web search, lot of suggestions are to bypass that 3AS. As 3AS is not connected through ECU, as later ones, then it should be quite easy. But understandably no-one writes it publicly and all information is changed privately.

That bypass sounds right first step for me. With that I could get engine running and make sure it is the immobiliser that is dead and not letting to start the car. After that I can focus on new alarm / immobiliser installation.

Before starting joining other forums where I read about that 3AS bypass, I’m interested in, do any of you have this bypass information? Or do you know someone who had that issue and solved it with bypass and could give me right steps to do it?

If you do, please let me know through Pm.