Anyone had a CEL come on and a code P2818? Today on a cruise I had a CEL come on and a message that said Rear Axel System off. I called Onstar for a diagnostic scan and a single code came up as P2818. I only have 1200+ miles on it with no crazy driving or launch control pulls. There are several things that could be wrong when I entered the code. Has anyone had this code and repair done for it? I am calling my dealership for a appointment tomorrow but im curious if anyone had this fepair done.

Update… at 1700 miles after dealership did the maintenance system clean in the DCT, code did not return. As mentioned the dealership said valve body would need to be replaced but after the clean, CEL and code never returned. Service department said they can’t replace the valve body if the code and CEL did not return and part will be under my name for one year and kept at the dealership. It would be returned after one year if problem doesn’t return.

My question is has anyone have a code come back 500 miles later or the system clean did the job.

 

recommend you bring it in for service, to get it resolved and for record purposes.

 

I found this in the 2020 Service Manual.

 

Sorry to hear you are having an issue with the car. Hope it is nothing major and you get the car repaired quickly.

 

I’d start and turn off the vehicle 10 times to see if the code disappears.

sometimes codes are set for little to no reason and then they go away and stay in a history mode and nothing more.

just something I would consider.

start and turn off ignition ten times to see if the code disappears

good luck

 

I had a C7 Z51 and a similar message would occasionally appear and disappear. Eventually the message stopped appearing.

 

Yep many safety sensors that can generate ~100 CEL codes per this Corvette tech. Worth watching for the OP, as the CEL may go away without a visit to the dealer. May go away with a simple flush the dealer will be told to perform, especially with few miles that could be caused by debris from initial wear
.

 

Jerry - awesome video!!! Thanks for sharing. One of your more informative posts yet.

 

With what seems like more and more of these occurring, is this not something they can do prior to shipping the vehicles from BG?

 

^^^^
Would not be beneficial, IMO until there was some initial wear on particularly the 1st gear clutch plates. I'll explain:
From my observation that is one reason I changed the DCT filter year one with ~3000 miles with OLM showing 5% oil life left, was a slight jerky motion when going very slow up to about 1000 miles

When I pull into my garage I creep as I watch the driver's mirror tip to door wood molding. I keep it at 1 to 2 inch max. That assurers the harder to judge passenger mirror clears. Below ~5 mph the 1st gear clutch MUST slip. Like my prior 5 standard shift Vettes if I didn't modulate the clutch car would stall! After ~1000 miles that jerkiness stopped and like now at 8,000 miles it's perfectly smooth. I attribute that to a high break-in wear of those multiple clutch disks.

Just a SWAG (Scientific Wild *** Guess) but a reasonable assumption. So you need some time on the DCT to get the clutch plates, shifting forks, Synchro cones, gears etc to wear-in.

The DCT is designed to slip with low pressure even when the car is stopped. It does not go into neutral. So that 1st gear clutch gets lots of initial wear. Would appear to me, waiting a minimum of ~1500 miles before a flush is logical. I waited until my 1st engine oil change at ~3000 miles. BUT GM says even if changing the DCT filter early also change at 7500 miles as wear-in continues. I expect as most wear it's high initially and tapers off with time. BUT I will change the DCT filter again when ALL DCT oil MUST be changed year 3 minimum.



The DCT is basically two 4 sped transmissions that have shift forks, Synchro cones, gears including the dif pinion and ring gear. Instead of rowing a stick, hydraulic actuators move the parts controlled by a computer. Lots of valves controlling the actuators. Wear debris can clog the valves. Probably the biggest benefit of a flush in back flushing those valves. Fortunately the DCT has many seniors that check the position of all those gears and shift folks BEFORE it switches from one clutch that operates one 4 speed to the next.

 

Thanks guys for the info. I have an appointment this Thursday and will post there findings and repair.

 

Thanks. Saved that since it's from a person who does have extensive DCT experience not just speculation- including mine!

Have lots of informative posts just have to be willing to read more than 280 characters and like pics! Have not learned to solve the World's problems with few words as others think they do with Tweets. Did learn many years ago a pic is worth far more than 1000 words!

 

UPDATE!!

So I have an update on the techs findings at my dealership. They did a scan and found one code {Control Sol Valve #8 Stuck} So he performed system test and clean valve body functions and a multi point inspection. Still has issue and ordered a new valve body. Cleared code and CEL and so far as before car is running and shifting smooth with no issues After 100 plus miles added, no CEL or trip codes. I will wait for the call when the valve body comes in with fingers crossed.

Any feedback or opinions on this issue from anyone that has this issue?

 

I had code P0700 (Trans Gen Trouble), P0868 (Trans Pressure Low), P0869 (Trans Pressure High) and P2724 (Pressure Control Solenoid "E" Stuck On). Dealer first tried to do the DCT flush which unfortunately did not resolve the issue. So they then had to replace one of the valve bodies inside of the transmission. While I was waiting on the valve body my car was driving fine as well. The CEL cleared but then came back a little while later but the transmission still seemed fine.

With the valve body replacement, they also replaced the internal filter, the external filter as well as all of the transmission fluid. This cleared all of the codes and so far so good. 🤞 They told me that in their experience, it doesn't take much to plug up a sensor or solenoid, even microscopic particles can cause these types of issues and codes. If the flush can't dislodge the particles, they have to end up replacing the valve body. The whole process didn't take long, maybe 3-4 hours while I waited for the vehicle.

This issue didn't sour me at all about the car or transmission. Both are awesome. It was a minor inconvenience and hopefully GM/Tremec is learning more about these types of issues and will make changes down the road to the valve bodies to make the sensors/solenoids less susceptible to microscopic particles.

 

Thanks for the info,so far CEL did not come on so far will see though.

 

Just makes us wonder where this stuff comes from and how it gets to the valve body without being filtered first. And, I wonder what "microscopic" means in this context. Small enough to pass through the internal, so called "lifetime" filter? Small enough to get through the external canister filter? I would have expected the external canister filter to remove anything big enough to clog a valve - suggesting this stuff already somewhere in the unit between the filter and valve body (that is assuming the filter comes before the valve body). I have also imagined that the internal "lifetime" filter is (based on its location in the pan) in the intake, and probably a coarser particle filter (which is scary, why is that needed?). There are also two magnets in the pan for collecting (obviously) ferrous metal particles.

I also wonder if an early DCT filter change, with the associated hydraulic system flush would have prevented what happened to your transmission. Perhaps once that stuff get in to and clogs the valve, its too late. And (speculating) the early flush avoids that by getting the debris out of the lines before it clogs a valve. There is a video on the forum about how foolish it is to change the DCT filter early because of all the diagnostic trouble codes that would have alerted the owner of the need to do that. But those processes do not detect the presence of this debris (microscopic?) until it has actually caused a problem. So, I did not entirely follow the reasoning in that video.

 

I suspect that the contamination that causes DCT problems is left over from the manufacturing process and somewhere between the filter(s) and the valve bodies. Hopefully Tremec has designed the filtration system to remove contamination that could cause problems.