Hmm,

I have a 2006 Jaguar S-Type 4.2 Litre V8. This is my first Jag...

About 3 weeks ago I put on new Adamesh Springs, Bushings, and Exhaust Mufflers

jaguar suspension and brakes | jaguar s type | lowering spring kit
Polybush High Performance Complete Bush Kits - 2003 - 2008 Models
jaguar s type exhaust | performance part

For three weeks the car ran perfectly...I mean phenomenal....I had my local garage install and no problems except they had to shave some of the poly bushings on front to fit...gas mileage improved even which i found odd.

so today, the dreaded check engine light came on....no codes, just the check engine light. i will take it into the dealership tomorrow for them to check it but do you think any of the above performance parts had anything to do with it?

 

Sounds like your device isn't working properly so isn't reporting the codes that will be there. Get one that works - see thread in General Tech.

 

Dealership says the car needs new catalytic converters now. I had worried about this because I had seen in some of the threads guys talking about needing new cat converters after changing the mufflers. anyone have any idea why this happens? any fixes? i really don't want to put new cats on this thing $$$. i have six months til my next emissions test so i can drive it til then but then what? I live in Dubai so we have this thing called Tasjeel where they inspect the car....

 

Can you retrieve the specific codes? Can recommend something from there...

 

Don't think the mufflers have anything to do with it. I changed my mufflers out 4+ years ago and have all the original cats at 105K miles. Almost 60K miles with the changed mufflers (Excuse me – rear boxes).

What takes out cats is either mechanical damage or running the car rich so the cat has to burn all that excessive fuel off inside itself. These will create very high temperatures which can damage and destroy the ceramic honeycomb.
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Thank you. The codes are: P-0175 and P-0172

Tech said both banks have gone. My local mechanic did clean the injectors when he put my new parts on and I recall he used some fuel additive to do this. I didn't think much of this at the time though as I was focused on new springs and "boxes" (mufflers) and grill.

The dealership cleared the check engine light. Tech also reminded me they don't test emissions ( I sometimes forget I am not in LA).

Car runs great. Dealer offered to replace cats for $3k. I said no thank you. I am content to drive with no cats but I hate check engine light. If i drive with no cats any harm done? If not how can I control check engine light?

Also car now has 60k kilometers (only 38,000 miles).

 

Those aren't catalyst efficiency codes...

Bank 1 and Bank 2 too rich codes...

Not sure if its' going to have anything to do with the cats to be honest...

You should get your own OBD scanner with live data to help diagnose further...

 

Cheap device with live data: ELM327
BT for most devices or WiFi for iPad