Hi to all on this site.

I've just joined and would like to say thanks for all your suggestions on the non/bad starting probs with xj6 models.

I bought my lovely xj6 a couple of weeks ago and drove her over 200 miles home without a hitch. Then for the next few days took her out for short trips of about 20miles. Now this may be a coincidence or it may be at the heart of the problem, I recoded my key fobs as directed so that both are now able to operate the locks. (Only one was in use by the previous owner as he did not the nerve to try and reprogram both). After making sure both were accepted by the devil living in the dashboard and all was well, I parked her up for the night. You guessed it, in the morning she started, drove 50 yards and conked out! I got her started 10 mins later and spent an hour trying every fuse etc to see what's gone wrong.

I reprogrammed the fobs and started her up. Ran for 5mins at 1500 rpm and slowly died. Then engine orange light came on and fault code reading P1621 showed on OBD. Took throttle housing apart and cleaned it and Idle valve. Still high rpm.

Twist is she now starts up and drives but if I use fobs to lock she refuses next time. I have to disconnect neg on battery count to 30 and reconnect. Then she starts up with no probs but runs fast. If she doesn't start I get out of the car leaving doors unlocked, press fob 3 times(eigther buttons) then she starts up!!! Disconnecting the battery only if she fails after this.

So if anyone has had a similar experience and found a solution I would be very thankful for your advice. The plus side is, if your xj does this to you at least you can get home by disconnecting the battery for a few seconds while doors are unlocked, reconnect and get in and start up without using the fobs. Hope this helps get someone out of a jam. Sorry if I've rambled but needed to detail for diagnosis.

Thanks guys.

 

Hi madjagden,

Welcome to the Jaguar Forums! It's great to have you with us.

First of all a couple of housekeeping issues. You posted the same thread twice about 10 minutes apart, so I deleted the duplicate thread. Also, your post was one large block of text with no line breaks, which discourages others from reading your post, let alone responding. Your thread had 241 views but no replies. I have taken the liberty of adding some line breaks to make it easier on the eyes.

My first thought is that it might be worth reprogramming your remotes just to rule out their programming as a contributing factor. Some online sources report that P1621 has to do with the immobilizer circuit, but I haven't found a definitive reference, and I don't understand why your car would start at all if the immobilizer circuit were triggered.

The fault code P1621 is not listed in the DTC Summaries manual for your 1996 XJ6, which you can download here:

http://www.jag.co.jp/test_tool/jaguar_dtc/AJ169679.pdf


My first suspicion would be that the OBDII scanner used may have returned an incorrect code. If possible, you might try having the car read by a different scanner. Most local auto parts stores will scan codes for free.

Hopefully others will have some suggestions.

Cheers,

Don

 

This is interesting, I have not verified any of it but it sounds like your symptoms http://www.jaguarforum.com/showthread.php?t=59665

 

I tried disconnecting and shorting the battery leads together today on my XJR. None of the effects described in the link above happened. The LTFT did not change and a pending code is still pending, so I don't think shorting the battery leads together does anything.

 

The ignition has to be switched on during the process and possibly other routines have to be followed too. Doing it as suggested in the referred to post isn't complete so it won't reset the system. See the explanation on Jaglovers in the XJ40 section.

OTOH, doubtful a reset would have any effect on the OP's no-start issue.


Cheers

Larry