P0603 Keep alive memory code.

[510PPV]

Anyone dealt with a p0603 Keep Alive Memory code on these cars? 2014, fresh rebuild with GP 2.5 LSA cam, kong ported LSA, id1050s, aux pump. Car will not idle unless we create a vacuum leak. Car ran fine when it came apart, put everything back together, all the grounds are good, alternator is charging and now we’re dealing with this.. No matter what tune gets loaded into it, it does the same thing. I believe we’re at the point where we are thinking a file got corrupted and screwed up something in the ecu and that our next step is to get a fresh ecu? What yall think? Any suggestions? Aux battery was deleted by previous owner.

[smwalker]

Check the fuse

Trunk fuse box
Fuse # F134

Labeled: ECM BATT

Amp rating: 10A

Cjrcyit description: K20 Engine Control Module

[JoeR]

For the stall, first thing I'd try is a Throttle body Reset with a good scanner.
Are you tuning it yourself or dropping in canned tunes?

Joe

[510PPV]

For the stall, first thing I'd try is a Throttle body Reset with a good scanner.
Are you tuning it yourself or dropping in canned tunes?

Joe

Throttle body is working as it should. Car is at a friends shop(he did all the work, I trust him.) As far as tuning, we’re working with a local tuner who is well known in the latemodel LS/LT world.

[JoeR]

OK. The P0603 is a TCM checksum error, so it's possible that it's related to the tune. If you're confident that's not it then it's most likely a bad controller. There's really no external faults that can cause a 603. A factory reprogramming of the TCM will tell you if the controller is bad. I'd definitely try that before replacing it.

I'm confident your tuner will be able to work through a closed throttle stall, but even with the throttle body working properly, these cars respond very well to a reset when they're acting goofy. Sometimes all a person has to do is touch the throttle blade before the pcm goes to sleep and it'll act like an idiot until you reset it. It's free to try if you have a good scanner, which I'm sure your tuner has.

Joe

[510PPV]

Put a new ECU in it and the code is gone, car starts and idles as it should with everything hooked up correctly.