Pass same exception thrown by upstream server to client with Nginx

Is there any way in which we can pass the same exception thrown by the upstream server to the clean where Nginx is acting as a Reverse proxy? e.g. I am using Nginx as Reverse proxy in front of some upstream servers and for some reason, an upstream server is returning a ConnectionTimeOut exception, but my client receives 504 GateWayTimeout exception. So my question is can we directly pass the upstream exception to the client so that client receives connection timeout exception instead of 504 GateWayTime out exception.