Renault Modus (2004 - ) - 05 1.6 Batt drains overnight, on random occasions

Honest John Back Room » Technical matters
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Mon 3 Aug 2009 12:57
05 1.6 Batt drains overnight, on random occasions - tunacat
A friend. let's call him Don, has a Renault Modus petrol automatic. At random, he will come out to it in the morning and find the battery flat or virtually flat; won't turn the starter motor anyway.
A jumplead start and it will go, and be fine again for days/weeks. The alternator and battery have been checked by both the AA and the Renault dealer, but deemed fine. The only fault code logged was to do with the Radio/CD, which the dealer said was a known potential cause of such an issue. They offered to replace it, for £450, or disconnect it. It got disconnected.

Don also got a new battery fitted, just in case it was a weird intermittent cell fault. That was at the end of May, and the car had been fine, until it did the same thing again this weekend. The AA man jumplead started it again, and Don *believes* he said that the issue with the Radio/CD draining the battery can still occur if it has not been disconnected "properly" (?). Don didn't indicate that the AA man had checked if it was disconnected properly, or done anything further.

Bit of a pooper though, never knowing whether your battery's going to be flat when you come to the car, even after it's been okay for 2 months. Equally, extremely difficult to determine exactly what component is draining it.
Just wondered if anybody else had encountered this problem on a Modus / knows of the solution?

Edited by Dynamic Dave on 03/08/2009 at 13:27

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Wed 5 Aug 2009 12:00
05 1.6 Batt drains overnight, on random occasions - Tornadorot
I guess one way to "properly" disconnect the radio/CD would be to remove it completely, though I expect this will require some special implement to extract it from the dash (which can often be found on eBay).
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Wed 5 Aug 2009 15:42
05 1.6 Batt drains overnight, on random occasions - piston power
Remove the fuse if it only supplies the radio and nothing else.

I have had similar issues with my car and found the glove box light coming on when it was shut by a faulty switch, i removed the bulb it "seems" ok at present, also these cars with the canbus wiring systems have to be locked up so the cars electronics shuts down does he lock it up or leave it unlocked?

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Thu 6 Aug 2009 13:29
05 1.6 Batt drains overnight, on random occasions - tunacat
Thanks for the glovebox light suggestion Bigtee - I'll check if the car's got one, and also what fuse is for what, next time I see the guy.

As far as I know, he always locks the car.

What with central locking, alarm, rain-sensing wipers, auto-headlights, anti carjacking, electric PAS... there are just so many possibilities for some errant circuit to drain a battery, given say from 6pm to 8am !
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Thu 6 Aug 2009 14:07
05 1.6 Batt drains overnight, on random occasions - madf
Each Renault comes with 10,000 designed in electrical faults and a random number generator in the ECU selects which one to occur and the time it occurs and its frequency.

For that reason, I steer clear of all Renaults.. With multiplex wiring , it is designed to make diagnosis impossible for the average garage.
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Fri 28 Aug 2009 22:03
05 1.6 Batt drains overnight, on random occasions - huttojon
I also have an '05 1.6 petrol auto which has now drained it's battery 3 times in two months!The local Renault dealer has failed to find any problem although he agrees that there is one!The car has now been returned to the supplying dealer with the objective of finding the fault and fixing it. I've only had the car for 2.5 months and can and will use the "Sale of Goods Act" if there is no satisfactory remedy.If they come up with anything I'll post it here.
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Fri 28 Aug 2009 22:44
05 1.6 Batt drains overnight, on random occasions - Simon
The local Renault dealer has failed to find any problem...
I've only had the car for 2.5 months...


I wonder if that is why the previous owner got rid of it???
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Wed 6 Jan 2010 21:21
05 1.6 Batt drains overnight, on random occasions - huttojon
The car ran fine until early December when once again the car dumped the battery and so was returned to the supplying dealer for repair.The car was returned with a new alterater fitted under warranty.I thought that this was a proper diagnosis until idle conversation with the dealer indicated that the faulty alternater diagnosis was on the basis that"it can't be anything else" no science was involved!The supplying dealer has been informed that if there is another failiure he gets to keep the car - my solicitor has all of the details as my patience and goodwill are all used up.huttojon
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Thu 7 Jan 2010 12:14
05 1.6 Batt drains overnight, on random occasions - tony@tooting
Canbus equiped cars can be a nightmare where parrasatic drains are concerned. Multiple computors that can "wake up" as soon as the car key gets anywhere near the vehicle in some cases.
I'm not supprised that the dealer is having problems with the Clio. To check for a drain they have to connect an ameter across the disconnected battery, close and lock all the doors, boot etc, and then wait upto an hour, just for the ECu's to go to sleep. If no drain is present during that day, then as soon as the gauge is switched off, or the battery in it goes flat, you have to start from fresh again in the morning. If you do get a drain, open the doors and all the ECU's wake up! How are you going to know what one was on? You then have to try and check the power usage of each and every one in turn. And dont forget that all of this "testing" is done in done in a workshop enviroment, and not under the same conditions that you are using the car under.
(I take it you dont leave the keys/spare keys anywhere near the car?)
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Thu 7 Jan 2010 13:20
05 1.6 Batt drains overnight, on random occasions - WorkshopTech
I have seen renault electrics make grown men weep. Comment about keeping the key well away from the car is a good one to follow up. Good luck with it.
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Fri 15 Jan 2010 11:24
05 1.6 Batt drains overnight, on random occasions - ironclad
My 2007 1.6DCi radio failed to work and the temp and time on the binnacle remained on when car switched off last week - apparently a low temperature fault known to Renault. Battery then drained when car not used for two days but the unit will be replaced under warranty.
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Wed 29 Sep 2010 22:38
05 1.6 Batt drains overnight, on random occasions - Modusmadness

I have a 4 year old LHD Modus that has suddenly lost all power to the battery. Everytime the guys come out to look at it from the equivalent of the AA they shake their heads, start it and say 'it's the battery'. Now after 3 new ones and a long stand in the garage which cost me 82 Euros, and no clue as to what is happening to discharge it I realsied that it had rained the night before the battery went and I'm wondering if other people have had a similar experience?

Personally, if I can get it going I will then either drive it over a cliff or part exchange it for a horse and cart!!!

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Wed 29 Sep 2010 22:43
05 1.6 Batt drains overnight, on random occasions - madf

I find it incredible people still buy Renaults when a modicum of simple searching will show they are are prone to weird electrical faults for the past 10 years or more..

Even I know it..

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