error 1 28-300 L

I have used the search funtion but haven't found any help with my particular lens so please bear with me.

I have a 1D Mk2 camera and I am getting an error 1 code only when using my 28-300 L lens. I have cleaned and inspected the contacts thoroughly several times but still getting the error. what is unusual is if I install the lens just short of when the lock mechanism clicks the lens works perfectly fine. Of course this presents a totally different set of issues with it not being locked in place.

Has anyone else had this problem or know of a solution just short of sending it back to Canon? I'm going on a trip soon and don't have time to send this lens off in time for repairs. I used to shoot all of the time but life has gotten busy and my gear has been idle for a while.

The lens has been treated with great care, never dropped or abused, it was a very expensive lens and treated as such.

Any useful help is much appreciated.

The contacts in a Canon camera body are usually spring loaded. Lightly push on each of them to make sure that none are sticking. Also, move the switches for AF and IS back and forth a few times leaving them in properly seated in the appropriate position.

Thank you for your help. I cycled the switches several times trying to get a clean connection. At first I thought that you were a genius, well you may be because that was a great idea. I thought it was fixed as the camera shot several photos without the error, but after half a dozen shots the error started again.

Your comment lead me to think that to try my old 5D with this lens and after about a dozen shots the error showed up again. That narrows it down to the problem being in the lens and not the camera.

I even tried fresh batteries to make sure low power wasn't an issue.

An odd thing to note is when the problem is about to occur the red square focus indicator is always very dim right before the failure.

Well I'm posting this as a follow up to my problem. Maybe someone else will get help from searching the "Error 1" tagline.

I am going on a trip soon and really need this lens working properly, I was hoping someone had a quick fix or hack.

Being in a time crunch I called Canon repair service and sought help and a estimated repair time frame. They were very helpful and gave 3 possible repair costs and a repair turnaround that fits in my schedule, approximately 2 weeks or less after they receive it.

I've had this lens for many years and even though it is a sealed lens it was in need of cleaning. Canon cleans the items as standard practice during repairs, which is a nice plus.

Just to be clear, Error 1 is a communication loss between the lens and camera. The advise previously made were great suggestions and I appreciate it, hopefully it will cure someone else's problem.