Need ECU reflash for S/C after swapping engine?

knowledge8069 · 07-04-2010, 12:07 PM

Do I need to have the ECU reflashed for the GM S/C kit after I replace the engine with another used one? It was already done a few years back when I first installed the S/C. Thanks.

widbyj · 07-04-2010, 03:55 PM

If you replaced just the engine (still running the entire S/C kit) and you still have the previously re-programmed ECU in place it will be fine once the crank learn procedure is completed. It should at least start and idle a bit rough at first then you'll need the tuning redone asap (dealer, HPTuner, etc...) like you would after any other engine swap. (I've done this myself already)

knowledge8069 · 07-04-2010, 10:06 PM

So I need to get the crank learn procedure done regardless? As long as it's not running too rough, can it be driven someplace to get this done or does it need to be towed?

widbyj · 07-05-2010, 03:53 AM

I drove mine from the shop to the dealer without any trouble but of course was going very slow and easy, less than a mile. I'd probably had it towed if it were any further, just to be safe? Then again, I was putting in a new crate motor so expected no problems. I've been told that any good auto shop with up to date OBD/CAN scanners can do it too.

knowledge8069 · 07-05-2010, 12:13 PM

Got it, thanks!

knowledge8069 · 07-07-2010, 12:53 AM

Ok everything is back together, starts up, engine running smoothly. Noticed that "trac off" light is on now. Pushing the traction control on/off button has no effect. Is this something that gets fixed when the crank learn procedure is performed? Also it shifts into drive a little harder than normal.

widbyj · 07-07-2010, 05:01 AM

Seperate issue - check hub sensor wiring, you may have a bad hub...

wrestlingandrunning · 07-07-2010, 10:34 AM

Quote:

Originally Posted by knowledge8069

Ok everything is back together, starts up, engine running smoothly. Noticed that "trac off" light is on now. Pushing the traction control on/off button has no effect. Is this something that gets fixed when the crank learn procedure is performed? Also it shifts into drive a little harder than normal.

Does it kind of rev up too when you shift into drive?

Cliff8928 · 07-07-2010, 01:09 PM

Quote:

Originally Posted by widbyj

Seperate issue - check hub sensor wiring, you may have a bad hub...

But is the ABS light on?

knowledge8069 · 07-08-2010, 11:26 AM

No it doesn't rev up when shifting, just goes into gear a bit hard. ABS light is not on.

Forgot to mention I also changed out the front coil springs because the car was sagging a bit, if that could be relevant to the "trac off" problem. I didn't unplug the hub sensors when replacing the springs. Is it likely that the wires got broken somewhere from stretching? I read somewhere to check the resistance of the hub sensors, like widbyj was saying. Both showed around 1150 ohms, within the required range.

Update: Checked the wires to the hub sensor up to the first 20", no breaks. Maybe in the engine compartment? Where does the other end connect?

Cliff8928 · 07-08-2010, 01:47 PM

If the hub sensor was bad you would have your ABS and service vehicle soon light on, so that's a non-issue.

Is the service engine light on? P1336 is the CKP Variation code (Case Learn)

knowledge8069 · 07-08-2010, 01:56 PM

Yeah the Service Engine Soon light is on, but it was already on due to my catalytic converter guts being punched out. I'm in the process of replacing that when I get some more cash.

There probably is a CKP code behind that, it's going to get towed in about 30 minutes to have the case learning done. Hopefully it clears the "trac off" light. I read that the PCM regulates the traction control, so if the PCM is not right then the traction control may also not be. I'll let you know later tonight once the case learning is done. I just wanted to check with you all first to make sure the stealership wasn't going to pull something extravagant on me. =)

Cliff8928 · 07-08-2010, 02:05 PM

When certain codes set, the PCM will disable traction control as it is controlled via timing.

knowledge8069 · 07-09-2010, 11:04 PM

Ok got the crank learning done, all warning lights are off. Apprently there was a transmission harness loose, so I think the "trac off" was from that. Thanks for the help!

alero_bmxer · 07-10-2010, 01:11 AM

if your iat sensor isn't plugged in it will cause the car to shift hard from neutral to drive and usually 1st to 2nd also. when i got my WAI i forgot to plug it back in and it did exactly what you described.

knowledge8069 · 07-10-2010, 01:45 AM

Probably what it was.