Hi all, 2005 Skoda Fabia 1.4 mpi 16 valve 100hp. Been in for repair and failed on emission as - 

• Exhaust carbon monoxide content after 2nd fast idle exceeds default limits (8.2.1.2 (b))
• car had been putting out fault codes before going in for MOT and I recorded then cancelled before sending in. These fault codes were as follows:
• Faults
   
  17584 Oxygen Correction Behind Catalyst, B1 Limit Attained
  17598 oxygen sensor. 
  17586 Linear 02 Sensor / Pump Current Open Circuit
  17550 - Load Calculation Cross Check: Lower Limit Exceeded, this could be poss caused by a dirty throttle body or defective MAP sensor, 
  17769
   17769/P1361 - Cylinder 3 Ignition Circuit: Open Circuit
  Possible Symptoms 
  • Malfunction Indicator Light (MIL) ON
  • Misfire
  • No Spark
  • Possible Causes 

  • Faulty Ignition coil(s) with output stage 
  • Fuse(s) faulty
  • Wiring and/or Connector(s) from coil(s) to ECM faulty

  Possible Solutions 

  • Check/Replace Coil(s)
  • Check Fuse(s)
  • Check Wiring and/or Connector(s)
  
  Coil pack on cylinder 3 was replaced as fault code. as I said, car has failed on emissions and is in for repair at the moment. Mechanic is good, but struggling. Every time he tries a repair emissions are still wrong. Any ideas gratefully accepted. 

How high is the CO?

The one you've got in bold, 17586 may be as simple as a busted wire so have a look down on that gearbox bracket for dangling cables where the precat sensor connects into the loom. 

Has the 17769 gone away with the new coilpack?

 

Why is he struggling, it needs a new post-cat lambda probe.

 

Edit: or a new cat

Edited 26 March, 20197 yr by sepulchrave

If CO is too high then most likely the CAT is faulty, perhaps its blocked or collapsed internally which could be the cause of some of the other errors.

 

Edited 26 March, 20197 yr by xman

1 hour ago, sepulchrave said:

Why is he struggling, it needs a new post-cat lambda probe.

 

Edit: or a new cat

Except the linear O2 sensor is the precat one...

 

Edit, oh, and please check the wiring where mentioned before rushing in to change that sensor. Wiring in that area of these cars is commonly found to be broken, and four of the loom wires that go to the precat sensor are thin/flimsy 0.35mm² size.

Edited 26 March, 20197 yr by Wino

3 hours ago, Wino said:

Except the linear O2 sensor is the precat...

 

I did mean pre-cat, no idea why I wrote that.

I've just replaced mine for the MOT, if you have VCDS you can see the live readings in a few of the measuring blocks.

Hi All. Many thanks for all your help. By a big clean up the emissions are down and the car is through the MOT. Quote the mechanic, it’s not perfect. Looks like it’s going to be new pre and post cat sensors and a new cat at some point. As I said, thanks all.