i had a check engine light come on and had two codes. one for the #1 bank OX sensor which was replaced and the secondary air system and the system was replaced, pump, valve and solenoid switch . then i thought all would be well and then i drove the car for 3 days and the light came back on, now i have two more codes, the back Ox sensor again (low ) volts and one new code, i have no idea what it is. it was P2105. Tac that force shut the engine etc down and the car almost stopped running. it barely moved. until i shut it down and restarted and now it is running fine again with the ck engine light on. i looked it up and got two answers one said #5 fuel injector circuit open and the other the throttle control. so what do i do?? where do i look? for the problem.. i am starting to not like this car.. HELP!!! anyone have any ideas?? i am totally lost.

 

Hi Bigvettefreak,

In order to offer specific suggestions, we really need to know the model, year and engine of your car. You can add that info to your signature in your Control Panel so it shows up in all your posts, but in the meantime please post it in this thread. (Note that this is the forum for the X350 XJ8/XJR sedans - the car in your photos is an XK8).

Also, are you using generic online OBDII code databases to look up possible causes of codes, or the official Jaguar Diagnostic Trouble Code (DTC) Summaries manual or Workshop Manual? I ask because the possible causes listed in the Jaguar documents often begin with things such as problems with wiring, low voltage, etc., and not a fault in the actual sensor or other components involved. It can save money and time to rule out the other possible causes before you replace parts.

Also, please post the actual codes for the open injector circuit and throttle control. The codes are designed to reduce guesswork, so without them we're still guessing.

Thanks!

Don

 

i just checked the codes again in my 2006 XJ8L 4.2 and now i only have 1. code instead of two. i guess the car fixed the other one it self. now i have the P0137 O2 sensor circuit low voltage Bank 1 sensor 2. it is brand new.. It is a Bosh sensor, should i be using Denso? would that cause a problem? what or where so i look now?

 

The original sensor was probably made by Denso, but as long as the Bosch O2 sensor is of the correct type and has the correct electrical connector, it is probably not the source of your problem. Did the sensor come with the electrical connector already installed, or was it the "Universal" type that required you to install the connector on the wires?

Have you had any indications of low battery voltage? Low voltage, especially while cranking the engine to start it, has been known to trigger all sorts of erroneous DTCs on these cars.

The DTC Summaries point to problems with the O2 sensor wiring harness. The Workshop Manual has a procedure of Pinpoint Tests that you can conduct to check the wiring and diagnose the fault. You will need to disconnect the harness from the ECM, and that requires a special 5-point Security Torx bit with a hole in the center. I ordered a set from eBay for about $20.00.

See the Powertrain section of the Workshop Manual, page 2472 for the beginning of Pinpoint Test G258127p8. You can download all six sections of the manual in pdf format from the 'HOW TO' quicklinks thread near the top of the home page of this X350 forum.

But before you begin the Pinpoint Test, I would recommend that you confirm that the new O2 sensor is firmly connected to the harness, and inspect the harness connector for corrosion and the wiring for any signs of damage, and clean all the ground points used by the ECM. Note that the torque spec for the nuts on the threaded aluminum ground studs is just 6.5 ft. lbs., which is just a little more than hand tight. Several members have learned the hard way how easy it is to snap a ground stud off of the body.

You can download the Electrical Guide at the link below, which will show you where the grounds are that serve the ECM. Look at the Figure that shows the Engine Management System for your engine:

http://www.jagrepair.com/images/Elec...al%20Guide.pdf

Cheers,

Don

 

For what its worth, I have read also that it can cause problems if the front and rear O2 sensors are of different brands. Should be either both Bosch or both Denso, but not mixed.

I don't know if that is urban legend/apocrypha, but thought it was worth mentioning as I'd heard it could cause weirdness.

cheers
adam

 

Just wanted everyone to know all issues have been repaired and the ar is once again 100% thatnk you all for your help and ideas.

 

What did you do to resolve the issues, for future reference?

 

+1 on trosty's question. Please don't leave us hanging without telling us how the issues were resolved!

Thanks,

Don

 

i replaced the air pump, the divert er valve and the solenoid switch. then i replaced the Battery and that fixed all the low voltage problems.

solved all the issues. and i replaced the O2 sensor as well.. now the car drives like new with power to spare.