My autofocus suddenly stopped working and a code of r11 comes up.

Slow down your shooting. The "R11" indicates that you can take 11 more images before the buffer is full and the camera will stop functioning until the images are moved to the memory card.
Select a smaller file size. Nikon cameras allow you to select from several sizes of JPEG as well as a RAW and a RAW + JPEG file. These files vary in size. If you select a smaller file size, the buffer will take longer to fill, allowing you to shoot longerTurn off long exposure noise reduction. This function causes the camera to expose twice for every image, and this can fill up the buffer quickly as those images are processed and written to the card.

Step 3 Select a smaller file size. Nikon cameras allow you to select from several sizes of JPEG as well as a RAW and a RAW + JPEG file. These files vary in size. If you select a smaller file size, the buffer will take longer to fill, allowing you to shoot longer.

Step 4 Turn off long exposure noise reduction. This function causes the camera to expose twice for every image, and this can fill up the buffer quickly as those images are processed and written to the card.

Read more: How to Fix the R11 Error on a Nikon D40x Digital Camera | eHow.com http://www.ehow.com/how_6327343_fix-nikon-d40x-digital-camera.html#ixzz0wC3WxqrT

Hello,

Please remove the battery and and then insert it again and test to automatically reset the setting.

melnavz

What you need to do is, take back off were timer is, check and see if resistor is burnt out R11. If R11 is Burnt you will need to replace it.

nikon r09,r11, etc . it mean memory buffer of your camera. memory buffer is a temporary memory for your captured images before it store to memory card.
if r00 it mean, you can't take a picture, even 1 picture... that because the camera buffer memory is full.
the number of memory buffer will also drop if noise reduction on

There are some answers that may help you, here....
https://www.photo.net/discuss/threads/d200-autofocus-fault.170857/

You will need the interupter replaced the iris is closed down so the a/f will not lock on

You might like to check if the A/M slider switch on the lens by the Nikon label is set to A.
It sometimes gets moved accidently.
Set to M the lens will not autofocus.

This might be obvious, but is the AF / M switch still on AF?

when was the last time you had the fluid and filter changed? This trans should be done every 30,000. Is it shuddering as the torque converter locks up?

TSB 97-10-6 has a repair procedure for this ysmptom:

Vehicles equipped with an AODE or 4R70W transmission may experience a torque converter clutch shudder or vibration. This occurs under light to moderate acceleration above 56 km/h (35 mph) while in 3rd or 4th gear. This may be due to either transmission fluid breakdown and/or the Powertrain Control Module (PCM) calibration.

Verify that bulk fluid does not have moisture contamination. If suspected, use quart containers of MERCON®. Refill transmission with the proper amount of Motorcraft MERCON® Multi-Purpose Automatic Transmission Fluid (ATF) (XT-2-QDX).

NOTE: DO NOT USE MERCON® V.

Check emissions decal to verify vehicle has the latest calibration. If it does not, reprogram the PCM to new calibration level using Service Bay Diagnostic System (SBDS) or New Generation Star (NGS) Tester with May 1997 CD-ROM or later. Refer to the PCM Calibration Chart found at the end of this article for proper application.
NOTE: VEHICLES SHOULD BE DRIVEN A MINIMUM OF 480 km (300 MILES) TO WORK THE NEW FLUID INTO FRICTION MATERIAL.

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PCM CALIBRATION CHART Application Old Calibration Old Part Number (-12A650-) New Calibration New Part Number (-12A650-) 1996 Crown Victoria/Grand Marquis 49S/Canada/High Altitude 6-18F-R05/R11 F6AF-AE 6-18F-R11 F6PZ-DJA 49S/Canada/High Altitude 6-18H-R05/R11 F6AF-BE 6-18H-R11 F6PZ-DKA Mexico 6-18H-R05/R11 F6AF-KE 6-18H-R11 F6PZ-DMA Police 6-18I-R05/R12 F6AF-CF 6-18I-R12 F6PZ-DLA California 6-18M-R05/R11 F6AF-DE 6-18M-R11 F6PZ-DNA California 6-18N-R05/R11 F6AF-EE 6-18N-R11 F6PZ-DPA

Olympus web site for a repair or replace option.