CUP 260 Electrical Cut-Out

[sonicrisk]

Hey all,

Just wondering if anyone can enlighten me as to whether or not using this cut-out after every trip will cause the ECU to 'unlearn' any settings.

I have to use it as I've been caught out more than once with a dead battery after only a couple of days. Trickle charger not an option unfortunately

Cheers,

Nick

[robin]

The previous Lotus ECU appeared to use (main) battery backed RAM for storing settings. If they've carried on this approach with the current ECU then this is what I would expect to happen.

Cheers,
Robin

[Sanjøy]

I overheard a running in discussion with a man in the know that stated that if you pull the cut off all running in data is lost. Not sure if this is relevant to the data you mention. This was a 2011 car.

[neil]

I think you've got to leave it something like 30 seconds after you turn the engine off before you use the cutoff so that the ecu has time to shut down.

[campbell]

Just Mains trickle charger ruled out, or any type at all? There are solar ones I believe. No good if car is undercover mind you - which I suppose it is

[sonicrisk]

Thanks guys... I feared this was the case! The first time it died and had to be jump started, the dash showed the Engine Check light and the airbag light (still on 9000km later)... the car is not fitted with airbags which made me think the ECU had lost something... is it possible that the ECU can lose any of the CUP settings and revert to a base map?

The battery has left me stranded a couple of times now so I have absolutely no faith in it, so, I use the cut-out after every trip. I guess the ECU is starting from scratch every single journey then

I think I may have to fit a 'normal' battery to the car... which is heavier

Campbell: underground parking and no power sockets... doubly screwed!

[robin]

The airbag light is reset by the Lotus Scan tool (or similar). I had the same issue on my 240 that had harnesses fitted. Of course the light will just come on again if you disconnect the battery once more.

I suspect the 260 calibration is flashed into the ECU so won't be lost by battery disconnect.

On a car like that I wouldn't be too worried about the learned settings unless it's actually causing you problems. I think the learned settings are mostly to do with idling and emissions; if it doesn't stall you don't care about idling and you cannot care about the environment too much when driving a 260 cup

Cheers,
Robin

[sonicrisk]

Funny you should mention that Robin, the car does conk-out a lot more than is used to. Normally as you coast to a stop and dip the clutch.

I bought one of those OBDII readers off £bay a while back but haven't tried it out yet, may give me a clue and may be able to reset a couple of lights.

[robin]

Not sure the ECU OBD port gives access to the airbag/seatbelt pre-tensioner computer - if it does you may be able to clear the open circuit fault on the seat belt switches.

The car conking out is a sure sign that it's forgotten its idling settings.

Not sure what you can do really other than drive it more often so you can keep battery topped up and not use cut-out.

Cheers,
Robin

[neil]

Looks like you'll need a trip to Murrays - OBD readers cant clear the airbag fault, you need Lotus Scan for that.

I found this in a thread on Seloc from someone who's had a similar problem:

they had spoken to Lotus and had been informed that this is due to the battery isolator switch being activated before the ECU has had chance to shut down. This causes the ECU to revert to "default settings" i.e. non-Cup, hence it then looks for a signal from the airbags etc.

The manual states that "if the isolator button is used when the engine is running, or within 15 seconds of keying off the ignition, the MIL will be illuminated at the next key-on.