I am a high school teacher working with a donated canon 40D to loan to students for projects.

A student wants to shoot manual mode on the camera, but the lens (Canon Ultrasonic EFS 17-85 mm) won't fire. If I set the camera body to any other setting, it doesn't have a problem.

Is it a bad sensor? Can it be repaired/ worth the cost of repair? I've cleaned contacts and the lens looks to be in great working order. I'm assuming a former student has dropped it at some point but I didn't catch the error code until this year.


  • thank you @MikeSowsun ! It is the lens- a different lens does not have the issue and the camera shoots on manual no error code Sep 23 '21 at 15:35

The Canon EF-S 17-85 USM is an old lens design and it is well known for having ribbon cable issues which cause errors like you are experiencing. The flexible ribbon cable transfers focal length and aperture information through the lens body to the camera, and it is common for it to be damaged over a long period of normal use.

It is not worth repairing as the second hand replacement cost is about $100, (or less) and the cost to repair it would be more than that.

I would recommend replacing it with either an EF-S 15-85 USM or EF-S 18-135 USM. Both lenses are more modern designs with better optics and image quality.

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