I took my 2023 Z51 to run a couple of errands today. After the second stop as I was walking up to the car, it would not remote start. I got in and the car started normally, so I drove off without thinking to much about it. As I was entering the highway near my house, the car was running perfectly fine, but I noticed a check engine light. I pulled over, opened the My Chevrolet app and saw the message below about the Fuel Management System.

I turned around and drove home without further issue, and the car continued to drive normally under light to moderate acceleration. After getting home, I stopped and started the car, but the light remained on. After several hours, I tried to remote start the car and it did not work. The car would just click twice and sit there. I got in and started the car normally, but the CEL light remains on.

The car has 2500 miles and the only modification is a Borla S-Type exhaust that was installed about a month ago. I only buy 93 octane premium gas from the same Exxon station near my house and the tank is at 3/8 full.

Has any one seen this message? Are there troubleshooting steps to determine more information on the message and is there a way to reset the light? Any thoughts or ideas would be appreciated. @Andybump ?

If needed, I can take it to the dealer on Monday, but I would like to avoid the trip if there is a simple explanation and fix.

 

If you have the actual Diagnostic Trouble Code (DTC) - that will point to a diagnostic procedure.

 

What is the easiest way to get the DTC?

 

Code reader if you have one. Some places like Auto Zone will read it for you for free.
Also, remote start won't work if there is a CEL

 

I bought a scanner and the code is: P31D3

I cannot find anything specific, but it seems to be related to the valves on my Borla S-Type based on other posts on this forum with similar codes.

@Andybump

 

Exhaust flow control valve: P31D3 = Valve position signal exceeds lower limit. I suspect that your new exhaust does not have AFM valves, or the "by-pass" electrical connector is / was not seated all the way? Do u have a FSM? I skimmed thru my alldata and there are electrical tests u can do or just go check the fuse for the AFM system.

Tom

 

I could not find that code in the manual I have - it lists some 1500 or so codes but not that one. If it is related to the exhaust flow control valves in the muffler, it may be possible to solve that with the valve relearn procedures. There is one for the AFM valves "Cylinder Deactivation Exhaust Control Valve Learn." and one for the tailpipe flow control valves: "Exhaust Control Valve Learn". Each requires a scan tool to initiate the process.

In most cases, the Borla system re-uses the 4 actuators. They are removed from the OEM system, and then mounted on the Borla system. They normally always require a learn procedure after they have been disturbed - that would be the case even if the actuators were removed and put back on the OEM muffler.

The valves themselves are part of the muffler system - you just re-use the actuators. It is possible that a valve in the muffler is stuck or sticking as well. In that case - the re-learn will not work. It would be a defective valve. Other points of failure are the actuators and the harness and connectors leading to them.

 

Thank you for the code description. My car has the Z51 package which includes the NPP exhaust. The Borla S-Type comes with the four valves, but you have to reuse the factory valve actuators. The shop performed the relearn process when they installed the exhaust and everything has been working fine for the last month.

I reset the DTC with the cheap scanner for now and the CEL is gone. I ordered a Launch Creader Elite that will allow me to perform the relearn if the CEL light returns.

 

Thank you for the detailed explanation, as always…

As mentioned above, the shop did the relearn, but I read in other posts it might have to be done several more times. I bought the Launch scanner to do it myself if the issue returns.

 

After clearing the code, I took the car for a short drive this afternoon to test the various exhaust modes. I tried all drive modes while sitting in my garage and I could clearly hear the difference in each mode, as the exhaust valves moved. I cycled through them five different times before leaving my house. On the road, I let it go in and out of V4 mode a couple of times to confirm the second set of valves were working.

The CEL did not return, so I hope the issue from yesterday was a one-time event. If not, I will do the valve relearn with the Launch Creader scanner.