Error Codes , what they mean and how can I fix them.

Updated 3 months ago by Michelle Pool


E-2 errors are generally caused by the year not being correctly programmed into the meter, which causes the meter to think your strips have expired. The good news is, there's an easy fix. 

How to Set the Proper Date on Your Keto-Mojo Meter

  1. Open up the rear back cover of your Keto-Mojo meter and press the orange setting button just once.
  2. Look at the front of the meter to see the year displayed and flashing. Use the big  front (M) button just below the screen to advance the year; you'll need to advance it past 2050 if it's past the current year. Once you do that, it will revolve back to 2005. Keep pressing until you get to the current year.
  3. Continue to follow the setup procedure with the standard settings.
  4. Insert the code chip card that came in the box with your ketone strips, CH will show for a few seconds, (CH means CHecking). Wait until the code is displayed on the screen and make sure it matches the code on your vial of ketone strips. 


An E-U error means that the meter thinks the strip it's measuring has already been used. Typically this just means the strip has blood placed on it before it was placed in the meter and thus reads the strip as used.  To avoid getting an E-U error, follow the following steps with a new strip:

  1. Prick your finger with a lancet device. 
  2. Place a fresh, unused ketone strip in your Keto-Mojo meter, then wait while it checks the strip (indicated by "CH" on the meter screen. When the meter is ready, it shows the code that matches the testing-strip vial and the droplet icon will flash. (With glucose strips, the meter shows just CH for checking then the droplet icon flashes.)
  3. With the strip still in the meter, bring the droplet on your finger to the tip of the strip. On contact, it will suck the blood in via capillary action. (You need a droplet about half the size of a matchstick head; if you don't t use enough blood, you will get an E-F error, which indicates you used too little blood.)
  4. Wait as the unit counts down and gives you your result.

Want more information? Here's a super quick video on the E-U error code:


An E-F is a Fill error.

This error can happen for a number of reasons.

  • Normally your Ketone-Mojo strip doesn't get enough blood volume
  • If the strip is pulled away too soon
  • When the HCT result is above 75%.

Here are some tips to help you avoid getting E-F errors and ensure you get good blood flow for easy sampling every time.

  1. When you prep your lancet device, adjust the depth selector. Have your meter at hand ready to test, the check your setting of the depth selector; there are six settings for adjusting the depth of the lancet's pierce to accommodate everything from soft or thin skin to thick or calloused skin. With experience, you'll find the optimal depth for your skin. Before testing, make sure your lancet device is set to your optimal setting. 
  2. Wash your hands in warm water prior to testing. Along with helping to clean the area, it will create a little warmth, which can help with blood flow. (We also like to use an alcohol swab to clean the area before use.)
  3. Rub the area before testing to encourage blood flow to the extremity.
  4. Grip the finger you are going to test with your index finger and thumb of your other hand and squeeze for about 12 seconds before using the lancet. This increases hydrostatic pressure.
  5. Quickly prick your with the lancet device, then wait 4 seconds. Then gently squeeze around pricked area until you have a droplet about half the size of the matchstick head.
  6. Place a fresh unused strip in meter wait while it checks CH. When its ready the droplet icon flashes
  7. With the strip still in the meter, bring the droplet on your finger to the tip of the strip; on contact, it will suck the blood into the strip via capillary action.
  8. Let the meter countdown and give you your result. 

Following these steps, you should not receive an E-F error. With practice, you will get better at obtaining a reliable sample size. We find the glucose strips are the best to practice with because they are the most affordable.

Other Error Codes


Your batteries are too low. With low batteries the meter is not able to give you a accurate reading. You may also get other error codes if your batteries are low. Please change your batteries.


This appears when the ambient temperature is above or below system-operation range. The system operation temperature range is 50°F to 104°F (10°C to 40°C). Repeat the test after the meter and the test strips are in the system-operating range.

E-0, E-A, E-E, E-C

There's a potential problem with the meter. But don't worry--these easy steps should remedy the problem:. If the meter still doesn't work, contact Customer Support.  Don't worry-- all meters come with a lifetime guarantee, so we've got your back! If you're still having problems,

  1. Remove and reinstall the batteries.
  2. Ensure that year, date, and time are set correctly. (The year is especially  important).  (See a video on how to set the year, date, and time.) 
  3. Insert the code chip that came with your strips, then wait for "CH " to appear on the meter screen. (CH means the meter is checking itself). Wait until the chip code is displayed on the screen, then confirm that it matches the code on your vial. (See a how-to video for that here.) 
  4. Insert a fresh strip into your Keto-Mojo meter and wait while it checks and shows the code on the screen.
  5. Now, test with a blood sample. Everything should work properly. If you still continue to get the error, please contact Customer Support.

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