The Mégane II Owners' Club

Hi, I have the P0670 fault code when scanning the car but no dash warning lights. I have checked the battery and glow plugs and 1 is around 1 volt less than the others/battery. When cold the car idles lumpy, would the glow plug be the issue of the Relay ?

The glow plugs only help the engine start when it's cold, so wouldn't make it run lumpy on tickover. Unless you mean lumpy just after you've started it?

I've got the same error code.

I've read that the unit itself is fine but the GlowPlugs are what cause the error. Either because one (or more) have died or they are cheap ones.

I've ordered a set of Bosch plugs. I'll get back to you when I've fitted them.

If you have a voltmeter, test the plugs. (place the red on the battery and black onto the glowplug - if you don't already know how).
I had a glowplug out a while back and the indicator on the dash never came on.

Have you replaced your plugs ? I have a new one for the one showing low volts, will replace this weekend. Where is the relay located in case it needs replacing ?

Yes the car is only lumpy after start when cold. Once up to temp it's fine.

MeganeMule wrote:Yes the car is only lumpy after start when cold. Once up to temp it's fine.

Remove the cover and check to see if there is a voltage getting to the glow plug connector. Just pull one of the caps off, put the probe of your meter into the cap, and the other to the engine block, and turn the ignition on. You should have 12 volts for a few seconds. If you haven't, then you can start looking for the relay. With the cover off, you can easily check each individual glow plug by setting your meter to ohms/continuity and testing between the tip of it, and earth.
I'd put money on it being a glow plug first.

Sounds promising ! Yeah I did that check 1st and cylinder 4 is 11.2 volts and the others were same as battery at 12.46 volts, I have a glow plug and I'll do it at the weekend. Here's hoping !!

Just a heads up, after I did mine, I reset the obd error codes, and it wouldn't remove the error. The check ignition warning disappeared from the dashboard though. When I checked a week or so later, it had cleared itself?

So , started this morning like a pair of boots in a washing machine on a spin cycle !!, old glow plug replaced (measuring at a bolt less than battery) started after when cold and she's silky smooth ! Will check codes tomorrow when I have access to my Autocom. Also took out a sensor on the black pipe r/h side of engine as mentioned in another lumpy post and it was clarted. So cleaned that as well. Will monitor the situation !!

Fault code cleared and has gone !! Happy Days.