[adam123]

Heya

Currently have a Renault Megane 53 1.6 petrol and the engine management light has been on for some time. Not being a fan of taking the car into the garage, I have purchased an OBD scanner and the car has produced the following codes.

P0141 - Sensor Heater Circuit Bank 1 Sensor 2
P0010 - A Camshaft Position Actuator Circuit / Open Bank 1

The car runs okay, however on first starting when cold, there is a very strong petrol smell (similar to an old petrol car with the choke out) and sometimes struggles to not stall without keeping the revs on.
Also noted a significantly higher fuel consumption and possibly a small loss in power when warm.

I have looked up the codes and the following have been suggested
P0141 - Replace oxygen sensor

Any guidance would be greatly appreciated as I have been ripped off many times by garages who have replaced the wrong parts etc etc.
P0010 - Haven't had much luck with this other than it may be something to do with the VVT electrical system, maybe the solenoid or camshaft sensor.

Just looking for some guidance as to what maybe the problem. Not a fan of taking to garages as they seem to replace parts that don't need replacingetc and costs go up.
Possibly a couple of sensors malfunctioning and whether I need to replace them.

Thanks

Adam

 

[madnoel10]

Not all scanners are Renault compatible so you may be getting erroneous codes being thrown up.

Also even the best scanner won't tell you what to replace - it is only a guide as to where to look. For instance your scanner is telling you a fault has been found at one of the oxygen sensors in the exhaust but that doen't necessarily mean it itself is faulty. If the engine is over-fueling which it obviously is the same code will appear.

If the engine is difficult to start when cold or runs rough when warm then it may be the engine coolant temp sensor is faulty but it could also be due to a faulty ignition coil.

 

[adam123]

Thanks for your reply

Luckily I seem to have got a scanner that is Renault compatible but I deffinately see your point. Was just hoping that it narrows it down a bit.

To narrow the symptoms down a bit, I recently replaced the coil packs on service due to two of them failing - so hopefully it isn't that. The car itself isn't difficult to start but runs very rough when cold and sometimes needs a few revs applying to stop it stalling. However it is noticeably using much more fuel than it should be as a whole - therefore as you say, the engine is clearly overfuelling.

What you mentioned about the oxygen sensor possibly not being faulty and just picking up the fact the engine is overfuelling makes sense so maybe the first fault is causing the second fault.

Therefore the first fault (problem with the VVT circuit) may be worth concentrating on do you think? (and may rectify the second in itself)

The camshaft dephaser pulley was replaced last year, and the oil control valve (OCV/solenoid) was replaced at the same time. So I was possibly thinking a fault with the camshaft sensor causing the ignition of a cylinder when the pressure/fuel air mixture in the cylinder isn't at the optimum. This would surely cause a drop in power/increase in fuel consumption - and at only £20 for the sensor, may be worth a try.

Would be grateful for any thoughts

Many thanks again

Adam

 

[madnoel10]

Fully compatible scanners suitable for Renaults don't bring up PO codes but codes whuch begin with DF. Yes Monsieur Renault likes to be quirky.

It may be worth checking the wiring connections to the engine coolant sensor/s. If faulty the engine may think the engine is either hot when in fact it's cold and vice versa. The sensor/s work on the resistance principle so a faulty connection can cause the ECU to fuel incorrectly.

If a cylinder is misfiring then unburnt fuel will be entering the exhaust and the oxygen sensor will trigger a fault

Also have you removed the spark plugs to check their colour?