Bank 1

[CUPRACAR]

Help Bank 1

Can anyone help with this fault?

I have a 100-cell cat and since having it fitted I get this fault code every few days

16804 P0420 Catalyst System, Bank1 Efficiency Below Threshold.

My understanding is that after fitting a high performance cat the gas flow post cat is outside the parameters the ECU expects, and the fix is to space the post cat Lambda out.

Is the fault code above not a reference to the pre cat Lambda? I maybe wrong but I would have thought that Bank 1 was pr-cat and Bank 2 was post-cat, can anyone enlighten me.

 

[The MoffMeister]

if you speak to j@mes he had the same problem, he ordered some bits for the US that moved the lambda censor further away from the exhaust so not as much gas flow passes through the lambda, as far as i know he has had it for a good few months and no problems as yet!

 

[m0rk]

Bank 1 is the probe that sorts the fuelling.... it's probably failled

Do not move it with spacers.

reset the code, if it comes back - replace it.

Stretch, you're thinking of Bank2 - you shouldn't move or tamper with B1

 

[CUPRACAR]

Bank 1 is the probe that sorts the fuelling.... it's probably failled

Do not move it with spacers.

reset the code, if it comes back - replace it.

Stretch, you're thinking of Bank2 - you shouldn't move or tamper with B1

Mark

Am I correct in my assumption then that bank 1 is pre cat?

I have changed the post cat lambda and still have the old one; do you know if it’s the same part No as the pre-cat one?

 

[m0rk]

Hi

Yes, Bank1 is pre cat

Physically I think they may be the same, but the connector will be different (to stop people connecting them the wrong way around!)

 

[cordobabrendy]

the two connectors are different, the post cat sensor is 4 pin with a different moulding as mork says , to stop people connecting them up arse about face.
revo (and other) stage 2 maps should sort this?

 

[CUPRACAR]

Hi

Yes, Bank1 is pre cat

Physically I think they may be the same, but the connector will be different (to stop people connecting them the wrong way around!)

Thanks for the help I will check out the connectors tomorrow

 

[CUPRACAR]

the two connectors are different, the post cat sensor is 4 pin with a different moulding as mork says , to stop people connecting them up arse about face.
revo (and other) stage 2 maps should sort this?

I have stage 2 APR and I was told the software dose not ignore the bank 2 sensor as in REVO but as Mark said the prob is with Bank 1 sensor

 

[m0rk]

Normally if the cat is reported as 'below' efficiency then you 'need' to ignore the code

however, if either sensor reports a fault code, you should change them

luckily it's straightforward - just a pain to access

 

[CUPRACAR]

Normally if the cat is reported as 'below' efficiency then you 'need' to ignore the code

however, if either sensor reports a fault code, you should change them

luckily it's straightforward - just a pain to access

and expensive

 

[m0rk]

about £80 I'd say. and grazed & burnt knuckles

 

[techie]

Bank 1 isnt precat.

You will have Bank 1 probe 1+2

Bank 2 you wont have. These fault codes are for V configuration engines so you can tell what side of the engine the fault is on.

The above fault code is indicating that the CAT is not working as the second lambda probe is picking up hydrocarbons etc.

 

[CUPRACAR]

£96.00 for the post cat that I’ve changed and probably didn’t need to

 

[CUPRACAR]

Bank 1 isnt precat.

You will have Bank 1 probe 1+2

Bank 2 you wont have. These fault codes are for V configuration engines so you can tell what side of the engine the fault is on.

The above fault code is indicating that the CAT is not working as the second lambda probe is picking up hydrocarbons etc.

Now totally

 

[techie]

The 100 CEL CAT isnt doing a good enough job to remove the required gasses.

 

[CUPRACAR]

The 100 CEL CAT isnt doing a good enough job to remove the required gasses.

So we have Bank 1 sensor 1 = pre cat sensor

Bank 1 sensor 2 = post cat sensor

So if Bank1 sensor 2 is brought out of the gas flow slightly we may have a fix yes?

 

[techie]

Thats the idea of the spacer blocks.

 

[Balf2k]

Sorry to raise an old thread back up but I can't find one of these lambda spacers anywhere. I pm'd a guy on VWvortex forums but never get a reply. Does anyone know how I can source one of these, It's really annoying having to reset my CEL every week or so due to my 3inch DP and 100cell Blue Flame cat. Any help would be appreciated.