2010 SD4 - I have a rough idle that disappeared when I unplugged the speed inhibitor switch operated by the brake pedal, the car generally runs a lot better without this plugged in even though I’ve replaced it with a new one.
What does the speed inhibitor do exactly and what are the consequences of not having it plugged in? Current: MY11 SD4 HSE / Sterling Quartz 2010 caravan

Previous: MY11 TD4 GS / Bailey Bordeaux 2002 caravan

The Brake Switch supplies a signal to the FL2s Electronics (via the CAN) and helps control many systems.

It may be something to do with the Automatic Gearbox (False) Neutral that occurs when the car is held stationary, in gear, on the footbrake, (say) at traffic lights. Be aware that I think that this feature was only in the Autoboxes after the MY2011 (all SD4s have it and are after this date)

As it has a bearing on many functions, including ABS, I would not advise driving with it disconnected.

Searching in the Repair Manual for 'Brake Switch' gives 27 entries, but I am not sure why you chose the Brake Switch to look at before checking for error codes or mixture problems. FL2 XS SD4 Auto 2010 2012-2017 (21k - 91k miles) (MY2011)
FL2 Metropolis SD4 Auto 2014 2017- (16k - 77k+ miles) (MY2015)
Metro in its 11th Year of (Extended) LR Warranty / Full LR Service History
(Expensive, but Trouble/Worry free - hopefully?)

It isn’t the brake switch I’ve disconnected, it is the speed inhibitor switch that is adjacent to it, but by you mentioning “false neutral” that’s kind of making sense now. When fully depressed it must tell the gearbox to appear neutral to stop the car trying to creep forward. Therefore if out of sync it would give the sensation of a lumpy idle.
I don’t think there’s any harm it being disconnected until I can get it looked at. Current: MY11 SD4 HSE / Sterling Quartz 2010 caravan

Previous: MY11 TD4 GS / Bailey Bordeaux 2002 caravan

I’ll just add that there are no warning lights at all on the dash Current: MY11 SD4 HSE / Sterling Quartz 2010 caravan

Previous: MY11 TD4 GS / Bailey Bordeaux 2002 caravan

Thanks for reply.

Please can you tell me where in the Repair Manual & Wiring Manual your switch is, as I can only find 2 Brake Switches (Brake-Switch Diagnostic & Brake-Switch Fluid Level), and I cannot locate a Speed Inhibitor Switch.

Can anyone else help please FL2 XS SD4 Auto 2010 2012-2017 (21k - 91k miles) (MY2011)
FL2 Metropolis SD4 Auto 2014 2017- (16k - 77k+ miles) (MY2015)
Metro in its 11th Year of (Extended) LR Warranty / Full LR Service History
(Expensive, but Trouble/Worry free - hopefully?)

I have disconnected part LR005349 that is brake pedal operated and engages the neutral position sensor located on the gearbox, I believe it is the neutral position sensor that is faulty and the root of my intermittent transmission faults including gearbox stuck in one gear and not being able to move the shifter out of park as well as the lumpy idle.
Disconnecting this switch has made cruise controls unavailable but sorted the transmission faults.
I can live without cruise control until I get a new neutral position sensor fitted. Current: MY11 SD4 HSE / Sterling Quartz 2010 caravan

Previous: MY11 TD4 GS / Bailey Bordeaux 2002 caravan

Have you seen this explanation of the Autobox 'Stuck in Park' problem.
https://www.freelanderspecialist.com/freel...ck-in-park

Also I have seen a post on another forum saying a similar problem on a FL1 was solved by removing Brake Switch Connectors and using Switch Cleaner on pins.

I cannot prove it, but I think your explanation of switches is for FL1s and the less complicated versions of the FL2, I think that the SD4 switch only talks to the CAN Bus. (I may be wrong) FL2 XS SD4 Auto 2010 2012-2017 (21k - 91k miles) (MY2011)
FL2 Metropolis SD4 Auto 2014 2017- (16k - 77k+ miles) (MY2015)
Metro in its 11th Year of (Extended) LR Warranty / Full LR Service History
(Expensive, but Trouble/Worry free - hopefully?)