Canon EOS Error 01 (Err01) – The worst case scenario

Canon’s explanation of the Err01 is “Communications between the camera and the lens is faulty. Clean the lens contact.” Well, life can’t be that simple can it?
I’m sure there are cases where the lens contacts are indeed dirty enough to interfere with communication between the camera and the lens. There are lots of cleaning tips online including the ‘pencil eraser’ method. If that worked for you consider yourself lucky.

Here is the dreaded Err01 message:
Canon EOS XTi - Error 01

No amount of cleaning, resetting and swearing was going to make the error go away on this Rebel XTi. I’ve also verified that it wasn’t the lens, dirty contacts, or the firmware. So I decided to take a deeper look (literally) to see what is really wrong.
Canon EOS XTi - Error 01

Canon EOS XTi - Error 01

Canon EOS XTi - Error 01

It turns out that the internal connector pin that connects the lens contact pin assembly to the circuit board has burnt out! Yes, burnt. The connector was covered with green fungus-like powder and some gooey substance was underneath it. And there were black burn marks on the flexible strip.
Canon EOS XTi - Error 01

Holy crap! how could have this happened? My two guesses are:
A. There were excessive moisture/humidity build up along the contacts while the lens was being removed with the camera powered on. (very unlikely, but a theory nevertheless)

B. The lens motor overloaded the camera. Perhaps, this poor XTi was trying to auto-focus a huge lens for prolonged period of time and/or there were constantly higher than normal resistance from the lens barrel from your hand being in the way, etc… (very likely, especially when using non-ultrasonic lnses).

Canon EOS XTi - Error 01

Canon EOS XTi - Error 01

Canon EOS XTi - Error 01

I carefully cleaned the connector with alcohol. But as you can see, few of the connectors are burnt out and has disappeared from the strip. It’s obviously not going to work as is. But I’ve put the camera back together just to see if it behaves any different. Yep, just as expected – didn’t work. The camera throws same error as before.

Now, I either have to look for a donor Rebel XTi that has the pin connectors intact or the part itself. With some luck and careful soldering, I should be able to bring this poor EOS XTi back to life. Fingers crossed and eyes open on eBay! Although, I should probably contact Canon first to see if they can help me locate the part.
Canon EOS XTi - Error 01


  1. Same prob here.
    I have the Err1 on two bodies but only with the same lens.
    Change the lens contacts is not so easy, so I would prefer the support.

  2. Changing the lens contact is very complicated. The connectors are routed through the shutter box assembly. You’ll end up doing more damage.
    Best way is to buy a used donor that has different problem such as broken LCD or power supply. Then swap the entire back half of the camera.

  3. Buy another Canon XTi, a broken one to use as a donor. A broken XTi can be had for less than $60 these days. Make sure the donor camera has good shutter. Look for ones with LCD or power supply problems. Just make sure you don’t get a donor with the same problem as your camera. Then swap the entire front half of the camera. This is much simpler and safer than separating the shutter box.

    It isn’t that easy to disassemble and reassemble the camera. You do need to de-solder and re-solder an aluminum heat plate of some sort in the process. And there are quite a few delicate connectors and wires that needs to be handled carefully. If you feel adventurous, it is worth a try…

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