UK Car Repair Questions? Ask a Mechanic for Answers ASAP
I am sorry that you have not been helped yet. I just came online and saw your question
Although no immobilizer(anti-theft) system, does it have either factory alarm or aftermarket alarm system as what you are describing is classic symptoms of a faulty alarm control module
That is an antitheft module, so it does have antitheft. Let me see if I have the schematics for it
Sorry, had a family emergency.
I unfortunately dont have the schematics required for testing and will need to opt out to see if another expert does.