Tried Googling for codes CO413 and CO 414 after getting a diagnostic due to the “Rear Axle System Off” and occasionally “Service Rear Axle” light. Can’t find any info.

Where can I find a list of “C” codes?

 

First off we have no info on your car…what year, what kind of transmission, any mods ??…any recent maintenance??…below are the DTC’s for a 2017…you can see what “sets” that DTC and steps necessary to fix it…has your rear differential fluid been changed ??…check if the fluid is low…the last page where it says action taken is for your C0414.

 

Thanks for the info. It’s a 14 Z51, MT no mods. Took it to a dealer. They said they bled the system which got rid of the 413 code but they said the 414 code came back after a test drive. Told me that the whole rear diff needs replaced. Although, that’s what the info says from the service manual as you provided I have a hard time believing that’s what is needed since it drives fine. Would have thought the service procedure would have led the technician through more troubleshooting to determine the issue (module/sensor testing etc.) vs. just replacing the whole thing. To me it’s like having an O2 sensor code, replacing it with a new one which doesn’t fix the problem, then the next step in the service manual says to replace the engine. Doesn’t make sense.

 

You should have mentioned the service you had at the dealership…this helps us help you…we are not there to look over the shoulder of the dealer tech so my advise to you is to take it to a shop preferably not a dealer since they will just replace parts…at least someone can verify the level of the fluid…you can start there.

 

Thanks. This will help me to at least talk a little intelligently when I take it somewhere else for a 2nd opinion. Learning as I go with this issue!

 

Do you get the errors as soon as the car is started or some time later while driving? Immediate error codes are one symptom of a bad battery...

Ron

 

Always about 5 - 10 min. after driving. Makes me wonder if it has to do with it coming up to operating temperature.

I have had the battery checked and it shows okay but sometimes seems to turn over slower than others.

 

The car will crank longer in cold weather or if it hasn't run for a while. Fuel high pressure needs to be satisfied before the engine will try to start.

I don't want you to just start throwing parts at the problem - but a bad battery causes all kinds of electrical gremlins. and is relatively inexpensive to replace. C7 batteries seem to last 3 years or so although some will report 10 years.

Ron

 

Battery was replaced in September’22. Theoretically, should still be good but I know they can croak early. I have read where low voltage can cause gremlins but seems strange that it would isolate to this one issue and not others. Might be worth a try to get a new battery. Couldn’t hurt I guess.

 

The apparently most frequent low battery error shows up as a rear axle off error due to bad communications. But that does not explain the need to bleed EDIFF control hydraulic fluid. I would certainly investigate further before agreeing to replace the differential.

Your battery should still be under warranty. You should either get a free exchange or a prorated $ exchange depending on where you bought it.

GL

Ron

 

First... as noted just above, how old is your battery? Otherwise "identical" products can be all over the ballpark for service-life. If you opt to change the battery yourself, do NOT disassemble the stainless steel "L"-shaped buss-bar bolted to the POS battery post, despite a PDF mentioned here on the Forum and a referenced youtube vid saying to... doing so is a totally needless source of potential hassle (trust me on this). Just unbolt the hole mess as a unit from the POS post and use a bungie-cord or piece of twine to tie it up/back out of the way so you can get the aggravating battery out of its "hole." All the best, in any event.

 

Thanks for the info. I’m already pondering how I’m going to get it out of the hole. It doesn’t have a handle and I’m not very strong.

 

They make an inexpensive strap that latches on to the battery posts.

Works pretty good but you still need to be careful.

 

Thanks. I check that out.

 

I couldn't get my big hands through the hole while holding the battery. I didn't have good luck with the battery strap. I finally slipped a couple loops of rope under the battery and made kind of a cradle. From there I could lift the battery up onto the floor. I made damn sure that my new battery had handles!

If you try a strap - it only fits one way - the battery posts are different sizes!

Ron

 

I have the service manuals. C0413 and C0414? FYI, it's a 0 not an O all codes are a letter and 4 numbers followed by a dash and two alphanumeric for the sub-type. If you get the Hexadecimal version its a Hex Letter followed by 3 numbers. All codes start with B (Body), C (Chassis), P (Powertrain), or U (Universal). I'll go look those up.

 

Service Manual matches the All Data info posted above in terms of description and most pieces of info (it has a little more info)

C0413 is Rear Differential Hydraulic System Bleed Not Perfomormed
C0414 is Rear Differential Hydraulic System

Clearing C0413 is basically done by running a routine. Sounds like they did that.

C0414 is not so good. Basically if you don't have other DTCs set (C0303, C0407, or C0411) then you need to check the rear diff for leaks, mechanical damage, and that the fluid is at the right level. If all that checks out fine it says, well replace the diff (assuming its temporarily limited)

Now do you know the sub type? Sub type 54 is that its overheating (this is always temp), 58 is that the clutch pump motor current is less than 5A (and disabled it for the key cycle). But you can't have a list of other DTCs because if you do it could be those causing the issue.

If you check the battery and its still bad. There is a module up under the rear of the car near the diff, it has two connectors, the one connector has 3 connectors going into the diff. On that connector the 8th and 16th Pin (Red and Black) go to a connector on the diff, those are the clutch pump you can disconnect it on the diff side and measure the current. Probably. This wiring diagram is a mess.

Hope mine never goes bad...

 

I've had both of my Corvettes experience the Serv Rear differential warning. It has been the alternator twice on my 16 Z06 and just recently my 19 ZR1. When they fail it's usually not long after startup and can cause all kind of elec issues. Just check it to see if it goes over 15 volts. It just overcharges.

 

Thanks for checking! This is good info.