Damn, I didn't even clock that was the later CEM. I even wondered why the component count on the PCB looked a little lacking. Sh!t, shows how long I've been away from the 400 series!
That explains quite nicely why you can't find the test mode ground jumper though.
As mentioned, CEM 3 should sing the fault song out the diag port in the engine bay. That's good news; the flash diag system is probably nicer and more accurate than the old 'test mode'!
Same principle applies on the testing, you just have to initiate the test procedures the way GJ has posted.
/Best of luck!
Chris...