Canon Err 01 lens communication error: how to fix it

Err 01 on a Canon EOS camera means the body and lens are not talking to each other properly, usually because of dirty contacts or a lens that is not seated well. These steps cover what Canon suggests before you book a service visit.

Switch off the camera, take the lens off, and very gently wipe the gold contacts on both the lens and the camera mount with a clean, dry cloth. Take out the battery and put it back, then refit the lens until it clicks. If Err 01 keeps coming back, try another lens to see whether the body or the lens is at fault, and take the faulty one to a Canon Service Centre.

• 1. Switch the camera off: Canon asks you to turn the camera off before you remove or attach a lens. Doing this first also stops the camera from trying to talk to the lens while you clean the contacts.
• 2. Take the lens off: Press and hold the lens release button and turn the lens until it stops, then lift it away. Put the camera down with the mount facing down so dust does not fall onto the sensor or mirror, and stand the lens on its front end so the rear contacts are not scratched.
• 3. Wipe the lens contacts with a dry cloth: Look at the row of small gold contacts at the back of the lens. Stroke a dry, clean cloth lightly across them, keeping clear of the rear glass. Canon warns against using a wet cloth and against touching the contacts with your fingers, since skin oils can lead to corrosion.
• 4. Wipe the camera's contacts the same way: On the camera mount, the matching contacts sit as small pins near the edge. Wipe them lightly with the dry cloth, without pressing hard. If the contacts look heavily soiled, stained or green, Canon suggests leaving them alone and taking the camera to a service centre.
• 5. Take the battery out and put it back: Canon also lists reinserting the battery as a fix for Err 01. Open the battery door, remove the battery for a few seconds, and slide it back in until it locks. Make sure it is charged, as a low battery can make faults harder to judge.
• 6. Refit the lens until it clicks: Line up the red or white dot on the lens with the matching dot on the camera mount, then turn the lens until it clicks into place. A lens that is not fully locked can give a communication error. Set the focus switch on the lens to AF, then switch the camera on and take a few test shots.
• 7. Test with another lens or body: If Err 01 comes back, try a different Canon lens on your camera, and your lens on another Canon body if you can. If only one lens triggers the error, that lens is the likely problem. If every lens triggers it, the camera body probably needs attention.
• 8. Write down the error and contact Canon: If the error still shows after cleaning and reseating, Canon advises noting the error number and contacting your nearest Canon Service Centre. You can find one through Canon India's service network page or book a camera service appointment from the Canon India contact page.