X Type / Engine Light / O2 Sensor / Code P1646 - FIXED
 

Hi Thought I'd podt this again with a better header. Please help - Very new to this forum. I have a 2001 Jauguar X Type 2.5 V6 with 60,000 miles on it. The Engine light came on so I went to local garage which I have been dealing with for 20 years. The computer said fault code P1646/7 = O2 Sensor upstream Bank 1 which we replaced at around £68.00 etc. After 20 mins the light came back on. Local garage said to take to Jag dealer as they didnt want to start guessing. However I dont trust the local Jag dealer after hearing a friends recent horror story £5k worth of guess work!. Local garage did a vacuum check, eyeballed exhaust, checked hoses and all seemed to check out ok. Today I took it to another local garage where a friend worked who cleared the fault but after another 20 mins and upon first start it came back on.
For a few months prior I did have a noise which came and went coming from under the car when it was cold. I wouldt say it was drive train but sounded like a rev related rattle which has gone now ie since the light started coming on. Your thoughts on relacing one of the Cats which may not be doing its job and is sending gasses back up to trigger 02 sensor? All help greatly appreciated. John Mc

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Hey John good to have you with us :icon_beerchug:.....a great intro story, thanks for sharing, but sorry to hear about your issues:icon_denk:

I really hope we can help you out and you enjoy your time here..... This is the new members section, you're unlikely to get the best help here....I've moved this to the X type area for hopefully better results for you my friend.

Good luck


If you like forums, I think you'll like it here! Some of the best guys around and a really great mix of information, camraderrie and fun :icon_rally:

I've manually upgraded you to full forum access so you can better view the site...................................

John, looking at the diagrams for your car, things are not looking to promising. Because you can replace an O2 sensor and the code doesn't clear, that would lead me to believe that you have good O2 sensors. This is where things turn ugly. That really leaves 2 other possibilities then.

Just to make sure you don't have the simple problem, check to make sure that fuses F38 and F42 in the engine bay fuse box are good. If both of these fuses blew, it is possible to cause the codes you are seeing.

If both fuses are good, then that leaves either a wiring issue between the O2 sensors and the ECM or the ECM is bad. This is where a detailed, hand over hand, inspection of the wiring harness will need to be done. Odds are, if you are going to have an issue, it will be in the passenger corner of the engine bay near the ECM. Otherwise, if the wiring harness looks good, it is looking like your ECM is giving you troubles. In certain cases, the plug on the ECM has gotten loose and a little bit of water will get into the plug and lead to problems like this. So, it could be something that simple. But, taking it to a professional shop to have them look things over is highly recommended before you start dropping big money on replacing the ECM.

Thank you for doing this. I am all over the place and finding my feet on the forum as I say many thanks for moving this to the better place. John.

Jim & Chris many thanks for your replies. The second garage I took it to mentioned that they would look at pre and post wiring etc so I will be taking it there on Monday and will let you know how I get on. Prayers its not the ECU! Its just such a great wee car and looks so good I dont want to lose it. Getting about 28mpg even as it stands just now. I run a one man outfit doing chauffeur,event,golf transport in Scotland so if you are ever travelling up here then all advice on how to and where to is freely available as indeed it is to all Jaguarforums folks. Not sure if I can put my website info on here for future contact in case I get sorted out with the car etc. Dont want to breach any rules or protocols. Will be in touch soon. Best regards - John

X Type Engine Light o2 Sensor etc
 

Hello to everyone. Good News. Its fixed. My own garage conceded defeat and referred me to another "New kid on the Block" Chris at CTH Auto Services based in Glasgow G13 4DJ. His reputation of having never been beaten is still intact! Chris nailed it down to being the other o2 sensor (RHS Lower) to that which the previous computers said it was (LHS Lower) For good measure he also replaced the other two upper ones all with Jaguar parts. Initially on driving it I found it to be a bit sluggish and a bit indecisive on gears but this has since got a lot better. Overall cost around £250.00 for parts so far and I have to go back and discuss the labour charges which I'm thinking will be around £150-£200.00. It is a lot of money I know but if you could see how good the car is looking you would understand why I was so keen to get it fixed. I hope it remains fixed as you never know with cars! I hope you all have a Great, Safe, and trouble free Christmas chaps and once again thank you all for being here. John.

Thanks for posting, and welcome by the way. Im a new member as well and I have learned a great deal here. Thanks for sharing your problem and especially the solution...I have the same code and I plan on changing the 02 sensors, now that I see what you did , I think I'm just going to change out all of them.
Thanks again and I'm glad you got the trouble sorted out!!

Thanks for your feedback , good to see you got it fixed
:)

Remember to do the preliminary stuff like hose and vacuum checks first before doing all of the sensors and use Jaguar parts. They don't seem any different in price from europart stuff bit that u could see anyway. Gokd luck sir.

thanks for this, im having the same problem, computer says bank 1,sensor 1... so replaced it... same error!! ... will continue with the diagnostics