Why is my 1997 Subaru Outback power light flashing 16 times when starting engine? Also Check Engine light comes on intermittently while driving?

If the CEL is flashing you need to stop driving. The rattling could be anything from a bad valve to a thrown rod or bearing within the engine.

Have the codes read. Check the brake fluid level. Wouldn't surprise me if low brake fluid doesn't kill the engine know days.

I found this under Fixya; 2006 Subaru Outback; there were 25 answers: The problem is not with an emission issue as you would expect with a check engine light. The ER 55 code on the odometer means that there is a loss of communication with the ECU, that is why the check engine light is on and cruise light flashing. for what ever reason whenever your check engine light comes on the cruise becomes disabled. Lame I know. I work in the service department and have seen this issue a lot. The only real way to fix this issue is to go the dealer and have them do a reflash for your vehicle. If the ECU is bad it is covered under the federal emmission wrty for 8 years or 80,000 miles

Fix your car right away by clicking the link I attached
2011 Subaru Outback 2 5L Workshop Service Repair Manual

not sure how that could be the cause, but check to see if vent valve is stuck closed. Otherwise, see my notes at link below.
Do It Yourself Diagnosis and Repair

First thing to do is have the computer scanned for trouble codes.

the check engine light comes on if there is a problem with thecomputer system related to the emmision, when this is is repaired the light on can only be turned off with a monitor,code reader. some of these are quite inexpensive.over the web or at a part store.

try disconnecting the + positive terminal for a few minutes and see if it goes out most likely the 02 sensor needs replacing ...however low fluid levels may also contribute to this oil,brake fluid etc.

under dash connect together the 2 green multiplugs. The CEL light (Check Engine Light) will flash. Slow then fast. Count the slow flashes then the fast ones. I.E. code 21 will give 2 slow flashes then 1 fast = 21.

let me know the code and I will diagnose for you.

Dan

I just bought a 1999 Outback with the same problem, the previous owner says replace the PCV valve

Hope it works