Hi again

Well, changing the front brakes was easy---wish I wouldn't have let it sit several months while thinking I was looking at a $400 garage bill.

Anyway, after not running for that time--now I have a Check Engine light on. The 97 car only has 73,000 miles on it and ran great today after the brakes were working.

My question is, is there anything I can easily check regarding the Check Engine light--or clean, ????? The engine is running just fine with all the power it normally has.

thanks again,
Darrol

 

The code!

OBDII readers can be had for very little ~$15 or, as it runs great, drop by an Auto Zone or most any parts store and they'll read it for you gratis. Ignore what they tell you it means and report back here with the actual code. You'll get lots of help. He who reads, may also clear...and you probably should clear it once you've established what it is, if it is a real problem, it will come back on, presently.

 

I'll do that

 

there were 2 codes
#1 02 sensor bank--sensor 2
#2 No DTC definition found

the code did clear but after driving it 100 miles it is back on

thanks

 

It would be preferred that you report the actual code. The reader interpretation is not all that accurate for Jags.

 

funomance,

The actual diagnostic trouble codes (DTCs) will be in the form of the letter P (for Powertrain) followed by a four-digit number. An example would be P0151.

I am attaching the DTC Summaries manual which gives you the actual Jaguar definitions of each code.

Cheers,

Don

 

The fault was P0139

the manual below shows that the code is

P0139 HO2S sense circuit slow response – Engine at normal operating temperature; drive 2 Refer to P0133 possible causes
cylinders 1, 2, 3 (A bank), downstream (2)

And P0133 possible causes are

HO2S contaminated
HO2S wiring harness high resistance fault
HO2S failure

Ok experts---what next?
thanks

 

Hi funomance,

You might think the "easiest" thing to do first would be to clean the electrical connector for the Bank 1 downstream Heated Oxygen Sensor (HO2S) to address possible corrosion that could add resistance to the electrical circuit (very common on Jaguars). I say "easiest" in quotes because the electrical connectors for the sensors are sandwiched between the rear end of the cylinder head and the firewall/bulkhead and can be very difficult to access.

If you are able to access the connectors individually, disconnect them one at a time, clean with zero-residue electrical contact cleaner spray, then reconnect before you disconnect another connector. The reason is that the connectors for the sensors are identical, but if you reconnect them to the wrong harness connectors the ECM will be confused, requiring a "re-orientation" procedure by the Jaguar dealer. If you must disconnect all the connectors in order to access any of them, use a paint pen or other permanent method to mark both halves of each connector pair so you can reconnect them in the correct pairs.

Perhaps a better first step would be to connect a scanner that can read live data and watch the signals from the four oxygen sensors to see if one is indeed responding more slowly than the others. If so, replacing the faulty sensor may resolve your issues.

Cheers,

Don

 

thanks Don

 

Hello
I had the live data test done yesterday and they said they could not get an accurate reading because of an exaust leak. They also mentioned a slow response from the 02 sensor and attributed that to the exaaust leak.
I have had an exasut leak for several months while it did not cause this Check Engine light. The leak is in the middle of the car and I was able to get a 4 inch exaust repair clamp around it--still does have a leak though. The leak may have gotten a little louder recently????? The mecahanic said that there may now be more than the one exaust leak and now causing the 02 slow response????
Anyway, I have some sheet metal that I will put around the exaust and then the clamp over that to eliminate most if not all of that one leak. Then get the fault cleared and see if it comes back on

unless anyone has a better idea

I checked several months ago on the cost of getting exaust fixed---almost $1500!!!! They said it needed from the header back to the last 3rd of the exasust.

thanks
Darrol

 

Hi
Well, I sealed the exaust leak well--however, when started the car it was still noisier than normal and so think I have another leak somewhere. That is what a mechanic thought also. The check engine light came back on within 50 miles.

I don't know when I will have $1300 to fix the ecaust. Will driving it with a small leak in the exaust damage any 02 sensor or the catalytic converter?

thanks again
Darrol

 

You probably want to get under your car and use some Gungum putty to seal up where you applied your fixes. If you do replace your pipes then consider a performance exhaust for the same money.

 

America wonders: what is gungum putty?

 

Hi funomance,

I may be wrong, but I believe that only leaks between the exhaust manifold gasket and the downstream O2 sensors can cause a check engine light. I don't believe a leak beyond the downstream sensors can be sensed by the Engine Management System to trigger a fault code and the Check Engine Light. So the leak you repaired in the middle of the car is probably not related to your CEL.

Please have the fault code(s) scanned again and post the exact codes here and we'll try to help.

Cheers,

Don

 

I believe that, as ever, Don is correct. Exhaust leaks under the car won't be contributing to this issue. Have you checked the exhaust manifolds? These are well known for cracking and causing exhaust leaks, and as you have two of them, it could explain a problem with a single O2 sensor.