an awful lot of Renault drivers suffer poor starting and a simple replacement of TDC or flywheel sensor solves it - might be carbon related - costs fifty quid or so plus a little labour in most places and main dealers don't seem to know about this common problem
The reason is because the steel tip of the TDC sensor which picks up a signal from the flywheel telling the ECU when to fire the spark plugs gets dirty after a year or two and cannot get the signal.
There is no need to pay up to ££90 for a new one at a Renault garage just simply remove it and clean the tip! also clean the connector.
Yes there is a coolant sensor in the Renault megane.
Renault Megane Dymanique
at the back
The coolant temperature sensor in a Renault Megane Scenic is located on the right hand side of the engine as you are looking at it. It is located just above the TDC sensor.
It has to be reset by a Renault dealer (or anyone with a Renault Clip diagnostic).
Next to the air filter box
On a Renault Megane Scenic, the output speed sensor is usually situated behind the gearbox. It can only be felt because it is small and has wires connected to it.
normally sensor is on drive shaft , but in some Renault models speed sensor is taken from ABS unit- if ABS itself is fine it could be due to fault in wiring. on some models you check speedo cluster (instrument panel) by pressing knob on instrument panel for about 5 seconds and all the dials start moving. if it works then it means wiring problem. only Renault can solve this problem ( french technology)
new tyre pressure sensor reset megane Sometimes resets if you blow up the tyre about 5 lbs above then adjust to correct pressure.
The sensor is in the near side wing mirror If you look at the bottom of the mirror you can see it
on the thermostat housing at the top of the engine block, normally secured by a spring "c" clip.
This should be mounted with 2 bolts on the top edge of the gearbox next to the engine where part of the flywheel should be exposed I believe