Talk Morgan Forums Thread Like Summary - M3W EML/CEL P0173 – What are my options?

My 2019 Three Wheeler has had an intermittent EML since I bought it, “P0173 Rear Adaptive Maxed Out.”
The car drives fine, and from what I understand, it is one of many common fault codes that these cars can lovingly throw at you.
Sometimes it disappears for a few dozen miles, other times it stays on for months.

Every year, the technician at Morgan resets and clears the code for me, but it always comes back no matter what.
He has always said not to worry about it, it is common, and to just ignore it – apart from a reset, there isn’t much they can do about it.

Whilst physically seeing the light is annoying, for 3 years now I have put up with it and enjoyed the car thoroughly.

The problem is, I’m starting to get to the point where I feel I want to sell the car and experience something new but selling a car with a check engine light and saying to a possible buyer “oh I promise the car is fine” won’t go down well, and will make the car almost impossible to sell unless I take a bath on the price. I doubt I could PX it, either, at least not for a reasonable valuation.

Obviously, I could have the fault cleared and try to avoid using the car until it’s sold in the hope it doesn’t reappear until it’s the new owners problem (which I suspect is what the previous owner did with me) but I’m not a dishonest seller and don’t feel comfortable doing that.

So, what are my options?
Is there a way I can log into the ECU and clear this code myself? I have got a copy of Pro Tune but it doesn’t really seem to give me any control.
Can I get the sensor that causes this EML “turned off” or increase the thresholds that cause it to go off, to prevent it from happening again?
There must be something that can be done – surely the car can’t be stuck with this forever?

True the adaptive settings are reset back to baseline if you power off the ecu for more than a few seconds, however it will quickly retune the adaptive settings next time you start the car. My car is garaged with the battery disconnected, sometimes for weeks at a time and I've never had an engine light issue.

With an unlocked ecu you can, if you like, merge the adaptive settings into the base map so it then uses a preadapted map as the baseline. For info my car is garaged with the battery disconnected, sometimes for weeks at a time and I've never had an engine light issue.

Depending on how open the aftermarket exhaust is it can require nearly all of the standard adaptation and if it goes out of range, even momentarily, it will trigger the engine light. This is then locked on for around 10 or so engine off/on cycles and if it doesn't go out of range again it will go out on it's own.

Krazy Horse have fitted a number of different exhausts over the years and most are fully OK with the standard ecu. I believe there can be an issued with the Demand Engineering "Demon" exhausts but can't be certain.

If you could find it an unlocked S&S ECU would be £500-£1,000 and the proven alternative Emerald ECU is £1,000 plus. However even on the stock ecu the engine should run OK with a suitable Stage 1 exhaust and functioning Lambda sensors.

For replacement Lambda sensors contact andy.warren@yahoo.co.uk as he can supply improved replacements cheaper than MMC. He may well have some ideas on how you can test the existing ones.

The other approach would be to swap the exhausts for stock. I have a virtually unused pair of stock exhaust pipes which you're welcome to foc if you can collect them from Sussex. Alternatively I am occasionally in Essex (nr Stansted) so you could collect them from there if the dates work.

As a last point - the check engine light is an MOT fail so it definitely would cause problems if/when you sell the car.