Any car mechanics out there?

[flymo]

Car mechanic? I have a question for you.

I have a Renault Megane Scenic RX4, Y reg. We went over a pothole and as a result lit up one of the warning lights that relates to the CAT converter. I've since plugged in a diagnostic box and got error code P0420 confirming the CAT fault.

My question though, is it more likely that the oxygen sensor/lambda sensor (is that even the correct term) that bolts into the exhaust right after the CAT is knackered?....or is it the CAT.

I've had the sensor off the car, cleaned it up etc and replaced. Cleared the error code and restarted the car but the code returns and the light stays lit.

Would appreciate any help please

[BanannaMan]

Most likely it is the O/2 (oxygen) sensor.
If you have a repair manual you can test the Ohms of the sensor.
Other than that... the only way to know for sure would be hooking the car up to a computer diagnostic scanner.
In this case worth what the garage will charge you to avoid buying/replacing expensive un-nessesary parts.

Hmmm - a Renault you say...

... in which case, I'd suggest frappez-le avec un marteau!



I'm not helping am I.

[flymo]

Originally Posted by BanannaMan

Most likely it is the O/2 (oxygen) sensor.
If you have a repair manual you can test the Ohms of the sensor.
Other than that... the only way to know for sure would be hooking the car up to a computer diagnostic scanner.
In this case worth what the garage will charge you to avoid buying/replacing expensive un-nessesary parts.

Ok thanks.

I think I'll take a punt on replacing the sensor, they only cost £30 or so.

I took the sensor out to clean it , I did notice bits of what looked like scale from the kettle but seems that it may be the remains of the ceramic coating from inside.

[Viney]

£30! Thats if you get a second hand part. They are/were something like £120 new when i went to get one for the Ashtray a few years back. Maybe Pattern parts have caught on in that area.

It will more than likely be the sensor though as its the only thing that sends a signal back to the ECU.

[flymo]

Originally Posted by Viney

£30! Thats if you get a second hand part. They are/were something like £120 new when i went to get one for the Ashtray a few years back. Maybe Pattern parts have caught on in that area.

It will more than likely be the sensor though as its the only thing that sends a signal back to the ECU.

Thats for a pattern part, the Bosch (and branded) ones are around £100 as you say.

[flymo]

Sorted, it was the Oxygen sensor, replaced it for £13, reset the error code. Bingo.

Saved me a fortune at the Renault dealer.

Originally Posted by flymo

Sorted, it was the Oxygen sensor, replaced it for £13, reset the error code. Bingo.

Saved me a fortune at the Renault dealer.

Renault, don't you just love 'em!
Just after Christmas my window wouldn't wind up - regulator (£250)
Car died on the way to work - TDC sensor (£150)
Had my Clio from new, on my 3rd set of pads/discs in 54,000 miles.

They must love it when I walk into Renault Wirral, can I come & see you next time?

[KeithCRM]

Originally Posted by The Beer Hunter

Renault, don't you just love 'em!
Just after Christmas my window wouldn't wind up - regulator (£250)
Car died on the way to work - TDC sensor (£150)
Had my Clio from new, on my 3rd set of pads/discs in 54,000 miles.

They must love it when I walk into Renault Wirral, can I come & see you next time?

Megane:
Last year my 72000 service; £700, replacement handbrake; £200, Trackrod end; £100. My employer told me to get rid, it was the most expensive car in the company to run (large BM's included).

Switch lights off; boot opens, aircon failed twice, engine mounts knackered.........I could go on.

Nice car but started to fall apart after 50K

nice work that man