Never again Honda - switching to Toyota. Thank You for info, I am going to scrap the car because they impossible to fix unless you know the right people or willing to gamble £100,000 + to get it fixed.
I sympathise. Can I ask, how did you/Honda establish that the ECM/ECU was at fault or was this just a guess?
I am waiting for our car to get really bad before I start messing around with things that could render it inoperable. Current value is about £2k. We have spent £200 so far on two garages (one local, one Honda) failing completely to identify the problem. The Honda centre recommended we buy a new immobiliser ring (£300) but failed to diagnose that anything was wrong despite the fault occurring for the guy on the shop floor who we left it with, while we were there. We had been on a journey for 30mins or so, parked it at the Honda place, it didn't start for him but then it was let sit for hours until the mechanics got around to looking at it. They probably had it running with bonnet open and doors open, ticking over for 10mins, therefore exposing maximum coolness, and the fault did not re-occur, which it would not do if temperature related. I find it disgusting that they would then recommend we pay for a new immobiliser ring with absolutely no justification when that is only one element of a system including the ECM, immobiliser receiver unit, immobiliser ring (possibly contains receiver, not sure how 'ring' part is defined), multiplexer module, parking brake switch, fluid level switch, inertia/(+tilt?) switch, probably more, and all the wiring and connectors that go between.
If it is the ECM then this is made by Bosch whose ECMs are also sometimes used in Toyota. As Rocky says, I think peak value from the car industry for the consumer has now passed. Like many manufacturers of electronic goods, it is now all about making money in the short term. Models are changed so frequently that reliability cannot be assessed before a new model is produced. All consumer car manufacturers (same for most consumer electronics) now produce cars that, on average, will now have a practical operational life shorter than the previous model due to the nature of design of the electronic systems, the lack of adequately trained staff in service centres (mechanics rather than electronics technicians), the designed-in desire for the user not to do DIY, an inadequacy of self diagnostic systems and the inevitable proliferation of intermittent faults such as the one we are seeing here. The manufacturer wants to keep the product you paid for under their control, as well as wanting to know how you use it, and dictate to you how you should - we are effectively leasing more and more of our bought goods now without realising it. And, generally, people are so unwise that they think that having more 'features' is always a good thing.
The late great Douglas Adams identified the problem through his brilliantly comedic skill with the example of shoe shops on a planet where civilisation had died out because the economy had collapsed because everyone kept on having to buy more and more shoes because they were intentionally getting made worse and worse to make more money for the shoe manufacturing cartel. Later, archeologists examining the strata record found a thin layer consisting of compressed shoes. Anybody that survived evolved into birds and vowed never to set foot on the planet surface again.