My check engine light is on in my Jaguar X-type 2003, and the car just failed the emission test. The code that they gave us was "P0057." What does this code mean?

the engine managment system on this car treats each bank as 2 seperate engines bank 1 and bank 2 the fault codes you have got are emission related. diagnosis is not easy because the ecu will use the other bank to compensate and alter its fueling etc to reduce emissions. the only way to sort it out is to put it on suitable diagnostic equipment and monitor live data ie. lambda sensors/ catalyst efficiency hope this helps

First step is to have the code or codes read.If the "check engine light" is on there will be a reason and should be a code or codes to be read.Once you have the codes,you can determine the correction needed to get that "check engine light" out and a valid emissions test completed.Get back to us with the codes found.

Probably not a cheap fix.
The car will not pass the test if the light is on during the test.
The light is on when the computer has a problem that will affect emissions or performance.
You would need to have the computer scanned for trouble codes then fix the problem. Once the problem is fixed and the code is erased, the light should stay off.

you can force the engine light to come on with ready or not software (type it in on google) i have this gear. your ecu has to reconise all emmissions sensors data on a 3times in a row before it will complete a full diagnostics cycle.
the ready or not scanner and software will atomatically do everything for you and tell you when everything is ready (so much easier than messing about guessing all the time).
you can also program scanner to your state regulations aswell.think it's about $50 now

hope this helps.

regards, danny

The person running the test is an idiot. The OBDII test instrument is not capable of determining if there is a warning lamp failure. It is probably guessing based on voltage level, but lamp resistance does normally vary. The test is supposed to be done visually. Take it to someone else, and they will probably be more competent and pass your car.

Hello
Does the light ever come on while you are driving the vehicle? It is possible that the vehicle does not trigger the code on the key cycle when vehicle is connected to the OBDII scan tool (a cycle is the time from when a vehicle is started to the time the vehicle is turned off) you should however most of the time be able to check a vehicles trouble code history to see what may be turning the light on
Good luck
Chris

This means your vehicle has failed to complete one or more of a series of self-diagnostic tests, usually but not always emissions related. The only way to find out which system has failed the test is to have the Diagnostic Trouble Codes read with special diagnostic equipment. Once you know the codes stored in your vehicle's computer, it will help determine what repairs are needed.

the check engine light comes on when 1 of about 200 separate faults has occurred in the electronic engine and emission control systems, when the light is on there is a fault code for the failed system stored in the computers memory, Kragen and Autozone and others do this test for free, ask for a OBD 2 fault code test or just say you have a checke engine light and need a test.

What codes come on? P0420

The converter's only purpose is to reduce emissions from the engine, in rare cases the converter can disintegrate which could result in a loss of power but this is not very common,

This means that you're Cat needs repair or replacement, You're car will not pass legally smoged without fixing this. :

Good luck

have you had a diagnostic code check? if not i'd start there. it sounds like it might be a oygen sensor, but before spending money on it, it really should have a diagnostic test to tell you exactly whats causing the problem.