Norcold RV Refrigerator "no co" Error Code reset instructions

For the second time since we've had the Holiday Rambler, we've got the dreaded "no co" error code on the digital display of our Norcold unit.  We nearly lost all our food the last time and I'm not currently sure that the food will survive this time - crossing my fingers.  So, apparently the way this happens is either the fridge did not complete its last cooling cycle, the fridge was jostled or off-level by a large amount, or poor ventilation.

Lower vent is where you access lower rear
of the fridge.

I knew that it wasn't poor ventilation.  I've been keeping a fan in the top compartment of the rear of the fridge blowing air out of the vents.  Since warmer air moves upward due to convection currents, the fan speeds up that process thereby helping the fridge to cool faster operate for shorter periods of time.  This is especially important for staying in warmer climates.

I'm not sure how you interrupt the cooling cycle of the fridge.  When we unhook from shore power, we don't turn off the fridge.  Since we keep the fridge set on "Auto", it switches between AC power and propane gas (LP) automatically when it senses AC power loss.  Anyone with any insight on this, I would appreciate feedback via a comment!

Behind refrigerator lower portion - The black
box on the left is where the control board is
located

The only possibility (again, I don't know the actual cause to why this happened either last time or this time) that I can think of is that we switched out the propane when we left our last campground.  So, if the fridge was in the middle of a cooling cycle (which makes sense) and was on LP, then it's likely that it didn't have pressure in the line to feed LPG to the fridge.  This is the most likely cause  - we just haven't been able to verify it as the specific reason.

So, how, exactly, do you bypass this error?  First off, if it's the first time the error came up, chances are that you can just turn the power off to the fridge and turn it back on.  According to the Norcold manual, this should do a "soft" reset of the board and eliminate the code.  However, if this is not the first time the code has come up, it will probably be necessary to do a "hard-wire" reset.  The procedure for this is neither difficult or intimidating.  The biggest thing is that you will need to ensure that you follow the disconnect/reconnect instructions to a 'T'.

First, you will want to locate to vent for the lower area of the fridge.  This is located directly behind (outside) the lower part of the refrigerator.  Undo the fasteners by turning the top part 45 degrees in either direction.  The top will come out followed by the bottom (held in with slot-tabs).  Set the cover aside for now.

Refrigerator Control Board

The control board is covered by a black plastic cover that is on the left side of the unit (as you look at it from the rear).  Remove the hex screws to access the circuit board.  Don't be alarmed!   If you don't have any electrical experience at all, you'll still be just fine.  This is a very simple (you won't get shocked if you follow the instructions!).  That being said, with anything electrical, there is always a risk of shock.  Have a set of insulated handled needle nose pliers.  This will simplify things for you.  Now that you're looking at the control board, either take a picture of how everything is currently connected, or make sure that you write down what wires go where.  The wires that we will be disconnecting are as follows:  12vdc hot wire (Red wire connected to tab labeled 12vdc on board) 12vdc ground wire (White wire connected to tab next to large cylinder on bottom right of board), 110VAC (unplug fridge from electrical outlet), solenoid gas valve wires (two white wires between 12VDC hot and ground wires) and lastly, the spark/sense electrode wire (connected to large black cylinder on bottom right - be VERY careful removing this wire.  Make sure you don't bend it to the left or right.  Pull straight out).
This procedure is also outlined in the image from the service manual below

After you've disconnected all of the required wires, connect the 12VDC hot and ground wires.  Turn on the refrigerator's power.  The 'no co' code should reappear.  This is where you will need to have a 6 inch length of wire to use as a jumper.  We are going to be "grounding out" one of the pins on the board.  This is known as a "hard wire" reset which resets the entire control board.  To accomplish this, Norcold recommends 22 gauge (very thin) wire with about a 1/2 inch of insulation stripped from each end.  This can be done with wire strippers or with a utility knife.  Once your wire is ready, locate the rectangular plug in the bottom middle of the board.  Release this plug by undoing the plastic connector (looks like a small hook - use needle nose pliers to undo hook and pull out plug).  Once the plug is removed, touch one end of the jumper wire to Pin 15 (top row, second in from the left hand side - this pin is the one directly to the right of the violet/white wire in the plug assembly) and the other end to the ground (shown in pic above or video) for about 10-15 seconds.  If you've done the procedure correctly, you will hear a momentary 'click' sound from the board.  This sound is the indication that the board has been reset.  It should also clear the 'no co' error from your fridge!  If, for some reason, this procedure does not clear the code, you may have to repeat steps 7-9 which are the steps to use the jumper wire to reset the board.

Once the code has been cleared, turn off the fridge.  Reconnect the remaining wires in the reverse order that they were disconnected.  When all wires have been connected, turn on the fridge and resume normal operation.

 If you are still unable to clear the 'no co' code, it may be necessary to troubleshoot the issue further.  There may be a problem with the control board or one of the components on the control board.  Since this is the second time the same issue has presented itself (and has been easily fixed by this procedure), I was initially worried that there may be a larger problem.  Since the entire cooling unit was replaced (under warranty) when we got the Holiday Rambler,  I was pretty sure this wasn't the issue!  The last time the code appeared, I sought out the answer by searching online for the error code.  It wasn't easy to find a resource that simplified the process.  I hope I have done that with this post!

Note:  Attempting to fix things yourself usually goes one of two ways - you either jump right in and start tearing things apart without first researching and investigating the problem.  Or second, you try to find as much information as possible on the problem and formulate a solution.  I bring this up because I used to err to "calling the 'guy'" to fix the problems instead of looking into them myself.  This can become both costly in time and money.  Besides, if you're dry-camping or "boon docking", chances are, you aren't going to be able to get a repairman easily!  I wasn't born handy - it was a combination of self-teaching and guidance from family, friends, and online forums.  The most difficult part is gaining the confidence in knowing that most systems aren't difficult to troubleshoot or repair, it's just a matter of gaining an understanding of how they work.  Once you know how something works, like a puzzle, you can figure out which piece is missing and take steps to correcting the problem.  That being said, I don't know everything, so if there is any advice or guidance that you can offer, please comment below or email us.

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