Hi,

I have a Skoda Fabia 1.2 12V (Motorcode (6Y) SEAZQX01) and on board appeared yellow check engine light.

Errors are:

17811 EGR System Regulation Deviation

P1403-35-10 Intermittent

16804 Catalyst System Bank 1 Efficiency below Threshold

P0420-35-10 Intermittent

I reset several times but still comes back.

Some say that gasoline is to blame others say it should be changed lambda sonde.

They are proberbly both connected to the same fault. I suggest getting the EGR checked and replaced first as that may also cure the second issue.

Im probably betting a cat fault if its done a few miles or had a missfire issue.

But it could well be an EGR issue, would be worth trying to generate a conformity code but you need dealer equipment to do that.

That's definitely a EGR problem. My old VAG car did that same thing, gave an error code for cat even though the problem was with the EGR solenoid, which wasn't working.

That is a perfectly normal operation, if EGR isn't functioning normally, it increases emissions and ECU calculates that there's something wrong with the cat... :p

To be more detailed, errors have occurred three times and removed after exactly 300 km. I reset the throttle (or cleaning) and the errors disappeared but after 1500 km the error appeared again. Also I driving the car at low speeds of 2000-3000 rpm.

When error occurs, I think the car has no "power" and even if I pressed the gas pedal I feel that not "pull" (Maybe it's just a feeling, because later the car wark normaly).

Cristian

Edited 30 October, 201015 yr by crior

Hello again, the error reappeared and now I have the same error:

17 811 EGR System Regulation and

16 804 Deviation Catalyst System Efficiency Below Threshold Bank 1.

If I reset the EGR, the error occurs after 1500 km else 200-300 km and not aftel 200-300 km.

Now I am convinced he is the EGR.

The service tested EGR, CAT and Lambda sensor and said they are OK.

It may be from driving in the city or driving with 2000-2500 rpm (3th gear).

Any suggestions?

Thks, Cris

We've done a check today:

I checked the EGR and it is OK.

I checked the two lambda sound (bank 1 and bank 2) and I find that bank 1 does not heat over 30 degrees. After, I kept the engine at 2000 rpm to 4000 rpm the temperature increased by 5 degrees, but still "not working" (not change the values of voltage 1.2).

What do you think?

Thank you all,

Cristian

Perhaps the heating element on the sensor has had it = new sensor.