Originally Posted by
GMPX
Hi Rob,
P0604 = Control Module Random Access Memory (RAM)
That is quite an odd code to be setting. The CSP conversion for that OS was released in April 2015, I don't know how many people would have used it before given it is an export model but there has been no feedback on issues with it.
Best I can probably do is flash this OS in to an ECM here and see if the code pops up here too. Though I don't know how much of a test that really is because on the bench LOTS of DTC's set when nothing is connected to the ECM.