Door replaced - car now in limp mode!

mikeee · 2025-08-14T09:54:13-0500

Ok the two are obviously unrelated……

But after returning a week later to pick up my car after a door replacement, the car is now in limp mode
(Reduced engine acceleration) max 4000RPM.

Called in to Silverstone on the way back and they say it needs to come in for exhaust valve diagnostics.

I do have the Milltek valve controller fitted but it’s been fine up to now….

Anything I can check myself to attempt to clear the fault or just let Lotus do their thing?
And any issues with leaving it plugged in or better to remove it and return to stock prior to them investigating?

Thanks!

mr.suntorytime · 2025-08-14T09:56:54-0500

mikeee said:
Ok the two are obviously unrelated……

But after returning a week later to pick up my car after a door replacement, the car is now in limp mode
(Reduced engine acceleration) max 4000RPM.

Called in to Silverstone on the way back and they say it needs to come in for exhaust valve diagnostics.

I do have the Milltek valve controller fitted but it’s been fine up to now….

Anything I can check myself to attempt to clear the fault or just let Lotus do their thing?
And any issues with leaving it plugged in or better to remove it and return to stock prior to them investigating?

Thanks!

the cables are known to melt and short out then blow the fuse in the fuse box. unplug it asap.

jp129 · 2025-08-14T09:57:43-0500

I would unplug the Miltek, return to stock, clear the code and see if limp mode goes away.

If it does, then it's the Miltek VC that failed.

Based on my experience, they appear to be "fragile".

mikeee · 2025-08-14T12:30:11-0500

Removed the rear diffuser and unplugged it and returned to stock - sorted.
Although I couldn’t see any obvious damage/melting to the VC.

Went for a spirited drive to test it and weirdly I didn’t miss that VC at all - most of the difference it makes is at low RPM where it makes it louder and cracklier but Sport mode above 4000 sounds good even without it - don’t think I’m bothered about getting it replaced.
But will see what 3rd cat delete alone is like.