E99 error with 17 to 85mm lens on some settings

This error message is common to a broken lens ribbon problem. Does the lens work in manual and not in auto. If so it could well be the problem. The fix is to have the lens ribbon replaced.

No there isn't Ian. What lens are you using just out of curiosity? There have been the odd issue with Tamron lenses causing error 99s constantly. Check your firmware just to be on the safeside - and keep it up to date if you can. Firmware is designed to iron out little kinks such as errors and other anomalies.

Hi turn on the camera with the lens on set to tv and a iris of f22 and use the stopdown button if the lens stops down the lens is ok if not the lens is faulty may need a intuper replaced

What wide angle lens is it need f number it may be to old to work on eos 400d

The 99 error is usually associated with a faulty pin connection. on the lens to the pin on the camera. Hers a trick that has worked in the past.
Use a pencil with eraser attached, gold the lens mount down while at same time you hold at a height you can run the rubber over the pins on the mount. Do the aame on the camera ensuring you dont get rubber bits inside camera. Finish off with a blast of copmpressed air feom a can and re assemble 99% of the time E99 disappears.

This could well be a serious issue, which you'd need to send to your manufacturer to fix, however there are a few things you could try first:

Take your lens off and with a clean rubber (like on the end of a pencil), clean the contacts of both the camera and the lens.

You will get that error when using some lenses other than Canon. A lot of the older Sigma lenses have that issue. Do you get this error when using newer Canon EOS lenses?

reset camera by removing battery completely for about 10 seconds.
otherwise, time for service.
sounds like a processor board issue.
you can use a contact cleaner sparingly, available from frys electronics or any other electronic reseller like radio shack.
good luck
mark

Your camera performs a quick 'integrity' check before each shot and goes into error 99 mode if the lens in incompatible or has a diaphragm problem. ( it will also display e99 if the shutter or flash unit is not ok but this does not apply here ). This is how you can check whether the diaphragm mechanism is ok : attach lens to your old camera and set camera to AV and set F stop to 16 . open back and release shutter and look through the back to see if your lens is closing to F 16. If it is closing fine then the lens is ok but is not compatible with your D400.

there are two possible problem of your camera...change first the lens or try other lens if you have,normally the lens have an error is on wide position...if nothing happen when you change the lens the possible problem is the shutter of the camera.......