1.9dci power loss solved!!!

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Beast Rider
Posts: 15
Joined: Wed Sep 19, 2012 7:09 pm
Currently Drives:: Renault Megane 1.9Dci 120 dimonique

1.9dci power loss solved!!!

Postby Beast Rider » Sat Jun 28, 2014 8:31 pm

Lady's and gentlemen I believe i have found the solution to an on going problem with sudden power loss while driving along.

I have a 1.9dci mk2 Megane Dynamique.

As have many of you, I have been plagued with the power loss problem and have exhausted every avenue in trying to figure it out without taking it to Renault and charged lots of money.

After trolling through the internet for about 18 months trying to figure this out I was nearly at a loss when I stumbled onto a possible solution which I didn't quite believe at first but on further investigation was entirely possible.

The solution I hear you cry.......

BRAKE LIGHT SWITCH!!!!!!!!!!

Apparently Renault and many other makers have written into the ECU program a safety feature that stops you from pushing the brake peddle and accelerator at the same time, this is controlled by the brake light switch, if the plunger is depressed it tells the ecu to kill the power to the injectors, over time the plungers get sticky and worn and stop working properly thus the power loss, the switch cost me £18 from the local parts shop and took about 2mins to replace without the need of ant tools and appears to have solved the problem.

I hope this helps a lot of people with the same problem as I have read a lot of stories of this on the net with no solution.

AlexB
Driving Legend
Posts: 4306
Joined: Tue Mar 22, 2005 8:17 pm
Currently Drives:: Renaultsport R.S.250 Cup

Re: 1.9dci power loss solved!!!

Postby AlexB » Sun Jun 29, 2014 11:44 am

Well done! I wrote about this cause several times before. Here, for example:

viewtopic.php?f=2&t=13227#p82387

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Re: Megane DCI no power

Postby AlexB » Mon Apr 26, 2010 1:51 pm
Check the stop light end-switch on the brake pedal.
AlexB
(no, a different AlexB)
AlexB
(no, a different AlexB)

AlexB
Driving Legend
Posts: 4306
Joined: Tue Mar 22, 2005 8:17 pm
Currently Drives:: Renaultsport R.S.250 Cup

Re: 1.9dci power loss solved!!!

Postby AlexB » Sun Jun 29, 2014 12:01 pm

Disabling throttle with the brake switch is a silly feature which comes from the states, where people keep crashing automatic cars by confusing left and right pedals. In sports manual cars, such as rs250 cup, this function is not present in order to give the driver more control over rotation of the car in extreme situations. Well, one needs to learn left and right first!..
AlexB
(no, a different AlexB)

Beast Rider
Posts: 15
Joined: Wed Sep 19, 2012 7:09 pm
Currently Drives:: Renault Megane 1.9Dci 120 dimonique

Re: 1.9dci power loss solved!!!

Postby Beast Rider » Wed Jul 02, 2014 8:20 pm

AlexB it was that post I saw it in, to be honest i didn't take much notice as everyone else overlooked it and was focusing on the EGR.

Also I just couldn't make the connection between the brake light switch and throttle, it didn't make sense to me until I did some more research.

Anyway thanks for the post, its a shame I didn't pay more attention months ago.

VroomVroomClonk
Learner Driver
Posts: 95
Joined: Wed Oct 02, 2013 8:37 pm
Currently Drives:: Megane 1.9 DCi CC 2004
Location: Suffolk

Re: 1.9dci power loss solved!!!

Postby VroomVroomClonk » Sat Jul 05, 2014 9:34 am

Wow! I've only just read this and I certainly hope you're right. My wife is out in the car at the moment, otherwise I'd be out there with the WD40 right now.

Alex, sorry, I never saw your old post about the brake switch. I did try various searches on the problem, but presumably I never got the right words for that one to come up for whatever reason.

This has bugged me for the whole year I've owned the car, and especially with Triumph2.5Man ending up doing major surgery on his injection system I thought there would never be an easy fix.

Many thanks for posting this and I'm certainly going to try it :D

fredcamp2
Learner Driver
Posts: 66
Joined: Mon Jun 30, 2014 8:57 pm

Re: 1.9dci power loss solved!!!

Postby fredcamp2 » Sun Jul 06, 2014 3:50 pm

The brake switch operates as a safety device in the event of a problem with the accelerator position sensor. If the brake pedal is depressed while the accelerator at a constant position the engine speed will drop to idle thus a faulty or incorrectly adjusted brake pedal switch results in a running problem Regards Fredcamp2

Purpleboots
Posts: 1
Joined: Wed Dec 21, 2016 7:51 am
Currently Drives:: Megane sports tourer (07)

Re: 1.9dci power loss solved!!!

Postby Purpleboots » Wed Dec 21, 2016 7:56 am

I am hoping that this solves my problem. I have the "check injection" torture message. It comes it goes,but not for good,and cat has lost its ooomph. :banghead :banghead :banghead

robbie1003
Learner Driver
Posts: 54
Joined: Wed May 25, 2016 8:19 pm

Re: 1.9dci power loss solved!!!

Postby robbie1003 » Wed Dec 21, 2016 9:48 pm

[quote="AlexB"]Disabling throttle with the brake switch is a silly feature which comes from the states, where people keep crashing automatic cars by confusing left and right pedals. In sports manual cars, such as rs250 cup, this function is not present in order to give the driver more control over rotation of the car in extreme situations. Well, one needs to learn left and right first!..[/quote

it actually is part of the system to help save fuel and also part of cruise control if you have it fitted.

Adam07Laguna2
Posts: 1
Joined: Sun Nov 18, 2018 9:18 am
Currently Drives:: 2007 Renault Laguna II

Re: 1.9dci power loss solved!!!

Postby Adam07Laguna2 » Sun Nov 18, 2018 9:29 am

Hi guys is this likely to be the same problem in a Laguna? I have a 2007 mk 2 and recently after a fairly long drive it's really down on power!
There are no warning lights and I can still hear the turbo kick in but it's like it's restricting the power.
Engine itself has done 100,000 miles and I've serviced it every time it's due, sounds perfectly smooth apart from a slight clicking noise it has made since I bought the car and has never caused and concern before, the clutch slips slightly when you floor it but I know it's due to be changed.
There's no smoke of any colour aside from a little vapour on a cold morning or bad smells and I would have thought if it was a fault with the turbo, EGR, MAF, injectors or fuel pump it would have triggered the EML at least!
So yeah it's left me a little stumped on the surface!
I'm going to code scan it tomorrow if I get chance and see if there's anything untoward there but I'm just looking for ideas if anyone has experience of this problem on MK 2 Lagunas :')
Cheers guys :)

VroomVroomClonk
Learner Driver
Posts: 95
Joined: Wed Oct 02, 2013 8:37 pm
Currently Drives:: Megane 1.9 DCi CC 2004
Location: Suffolk

Re: 1.9dci power loss solved!!!

Postby VroomVroomClonk » Mon Nov 19, 2018 1:32 pm

This brake pedal switch problem manifests itself as a very brief loss of power, see here - https://www.meganeownersclub.co.uk/forum/viewtopic.php?f=2&t=21585

That doesn't sound like the general " really down on power" that you are describing.


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