A fault I'm in no hurry to fix (Mégane 2)

CelticRambler

Here's one for the sleuths amongst you: "SERVICE" light is lit and the display reads "electrical fault" - the very first time in over a decade that this Mégane 2 has bothered to display an error message, despite all the many electrical faults its had in that time.

Everything's working except cruise control, and I've worked through the various check-lists suggested on the Renault and Megane-owners forums (not a member, though, hence posting here). The speed limiter works; the CC dash light comes on, but nothing happens.

Here's why I don't want to fix it: ever since I've had the car, it averaged 6.7-6.9l/100km until I had the timing belt changed, at which point it went up to 6.9-7.1l/100km (... ) But ever since this fault occurred, my fuel efficiency has improved, currently at 6.4l/100km, having briefly flirted with 6.2l/100km on a long drive last week.

The CT's good for another 20 months, so I'm in no rush to fix the problem - but it'd be nice to have Cruise Control back again! Any ideas? Any other tests I can do without resorting to an error code reader?

TheBoyConor

You need to read the codes. Otherwise you're going blind.

One thing you could try is disconnect the battery for an hour to discharge everything and then it might reset itself.

CelticRambler

TheBoyConor wrote: »

One thing you could try is disconnect the battery for an hour to discharge everything and then it might reset itself.

Already done. The SERVICE light doesn't come back on immediately, but the cruise control doesn't work. The error message inevitably comes back within about 10-15 minutes (usually a lot less).

TheBoyConor

Then you'll have to read the codes and go from there. Simple as that.

Mad_Mike

CelticRambler wrote: »

...Everything's working except cruise control...it averaged 6.7-6.9l/100km until I had the timing belt changed, at which point it went up to 6.9-7.1l/100km

Just wondering if this coincided with the timing belt job being done?
Is it possible that when doing the timing belt that somebody disconnected a wire/cable etc which has taken the cruise control out of action?

CelticRambler

This problem doesn't coincide with the timing belt - that was done a few years ago and somebody certainly messed something up at the time: when I went to collect it, the head mechanic sheepishly apologised for it not being quite ready, on the grounds that they couldn't get it to start! But once they did whatever they had to do to fix it, everything was back to normal except for the fuel consumption being very slightly higher than usual.

This fault warning just appeared out of the blue shortly after the cruise control refused to engage. Then I noticed that the displayed fuel consumption seemed to be unexpectedly better than average, and at this stage I know it's not an anomaly. I can get almost 900km out of a full tank whereas it was only around 800km before.

TheBoyConor

Fuel consumption and the loss of cruise control functionality are probably not directly linked to the fault. MPG probably improved simply because you are not using the CC anymore and and driving manually is giving better fuel economy.

CelticRambler

I'd only just started using the CC regularly, so the fuel economy is real for my driving style.

colm_mcm

There's no other answer other than read the code

or don't read the code.

CelticRambler

colm_mcm wrote: »

There's no other answer other than read the code

or don't read the code.

Fair enough. No possibility of reading the code in the foreseeable future; I just thought the weirdness might make sense to someone.

dieselbug

Fault codes stored in engine management will cause the cc to be disabled. Fix the fault and your cc will most likely be restored.