I am getting the following error with my EF-S 55-250mm f/4-5.6 IS II lens only when I zoom it beyond 135mm:

Err 01

Communications between the camera and lens is faulty.
Clean the lens contacts.

Can anyone tell me what can be the issue?


2 Answers 2


It looks like you have a problem with the aperture flex cable (ribbon cable). It is quite common on certain Canon lenses like the 17-85 and 24-105, but can happen with almost any lens.

When the flex cable starts to go bad it will interfere with the physical communication between the camera. Changing the focal length will put stress on the flex cable and cause the error.

Sometimes shooting wide open at f/4.0 will allow you to keep using the lens but the cable will need to be replaced

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  • \$\begingroup\$ Thanks for your answer. May be bad flex cable is the issue here. \$\endgroup\$
    – Pavan
    Commented Nov 5, 2015 at 10:54

Generally, the EOS Err 01 error code is prompted when the physical communication, IE, the contacts between the camera and Lens are not making contact.

A gentle wipe of the contacts on both sides with a clean dry cloth, normally does the trick.

Canon warns to not use a wet cloth or finger to touch any contact as it will encourage corrosion.

If that does not fix the error, you will most likely need to go to a service facility to have it looked at. it seems a little strange for this error to happen at a certain focal length and beyond only!


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