Sensor or Catylitic Convertor issue or both?

[Mils82]

Just purchased Golf plus 2006 60k very tidy, full service history etc on journey home engine warning came on. Took it to my local garage they cleared the codes and said it may be the Cc, however it was only replaced 2 years ago. Is it possible it is a sensor issue perhaps? Contamination in the converter?
Cheers.

[E-bmw]

What was the engine code?

Did they do anything else, as in actually do any diagnosing?

Don't replace anything without first knowing why.

Edited by E-bmw on Sunday 23 February 11:35

[Super Sonic]

As the sensor is cheaper I would replace this first. If the cat was changed for a cheap one, they typically don't last very long.

[Richard-D]

Mils82 said:

Just purchased Golf plus 2006 60k very tidy, full service history etc on journey home engine warning came on. Took it to my local garage they cleared the codes and said it may be the Cc, however it was only replaced 2 years ago. Is it possible it is a sensor issue perhaps? Contamination in the converter?
Cheers.

A better mechanic will look at the output from the lambda sensors (pre and post cat') and be able to tell if you have a sensor issue or a cat issue. It could be either from your description. There's every chance that a cheap cat' has failed after 2 years so recent(ish) replacement doesn't rule that out.

Short answer - find a better garage

[Mils82]

Thanks, engine warning is on amber suggesting its emissions?
It guzzling fuel time!
The lambda sensor was replaced on It's last mot in November. Before I purchased the vehicle.

[Mils82]

E-bmw said:

What was the engine code?

Did they do anything else, as in actually do any diagnosing?

Don't replace anything without first knowing why.

Edited by E-bmw on Sunday 23 February 11:35

The garage didn't give me a code. Is it worthwhile going to buy a code reader?

[E-bmw]

Mils82 said:

E-bmw said:

What was the engine code?

Did they do anything else, as in actually do any diagnosing?

Don't replace anything without first knowing why.

Edited by E-bmw on Sunday 23 February 11:35

The garage didn't give me a code. Is it worthwhile going to buy a code reader?

Better to beg/steal/borrow one for the moment, but without knowing what the car thinks is wrong & doing some proper diagnosis there is no point in wasting money by replacing random parts just in case you accidentally fix it.

[Megaflow]

Richard-D said:

Mils82 said:

Just purchased Golf plus 2006 60k very tidy, full service history etc on journey home engine warning came on. Took it to my local garage they cleared the codes and said it may be the Cc, however it was only replaced 2 years ago. Is it possible it is a sensor issue perhaps? Contamination in the converter?
Cheers.

A better mechanic will look at the output from the lambda sensors (pre and post cat') and be able to tell if you have a sensor issue or a cat issue. It could be either from your description. There's every chance that a cheap cat' has failed after 2 years so recent(ish) replacement doesn't rule that out.

Short answer - find a better garage

What he said. I wouldn’t be at all surprised if the cheap cat has gone south, but a decent garage should be able to tell you.

[Richard-D]

Mils82 said:

Thanks, engine warning is on amber suggesting its emissions?
It guzzling fuel time!
The lambda sensor was replaced on It's last mot in November. Before I purchased the vehicle.

Amber engine light isn't tied to emissions specifically. If your car has the capability of red then amber would usually mean 'non urgent engine fault'. I think that is the case with VW but your handbook will confirm.

Some vehicles change colour of light and some use a flashing light to signify a more urgent fault.

[Mils82]

Just done a code reading. P0420 ...
Cat efficiency below threshold... Bank 1.

So i guess Cat or sensors. Just need to find a reliable garage locally?

[paul_c123]

You need to look at the live data - O2 sensor voltages. If they look okay then the cat is at fault.