Do you think it's worth a gamble to get an ECU from a wrecked (but running) Aveo with everything matching ( year, trans, close on the VIN's , etc) , install it and drive or tow to the dealers and have them "attempt" a flashing ? Thanks . Off to work now will keep everyone posted ..
I have always wanted to try this, and even pondered it myself, as I too own two 06 aveos, and both have the exact same ECU/trans. However I chickened out since we drive both cars that both ran fine with the exception of some dtc codes. What I know will be different will be the VIN of the car, (wont match the used ECU) and the crank position sensor may not be calibrated, but I would think it would run ok..?? Just a theory at this point, since I have only heard of rabbit swapping in a used ECM for testing an issue. From what I have learned I think it would work in a testing application, but would need to be 'programmed' with the correct VIN at some point, and according to GM's tech documents, it should have a crank 'CKP' relearn to calibrate the sensor or you may see misfires, or false triggers for the P0300 code as the crank sensor calibration would be off.
But it should still run, as in the past I have swapped CKP sensors, as well as ECM's and did not need to do the relearn, but have yet to do this swap on an aveo. I have swapped the ECU in a 2003 Cavalier with success and no relearn, and I have changed the crank sensor on a 98 quad4 in an olds, and did not need to do a relearn and both cars still run fine today. So I tend to doubt the absolute need for a sensor relearn, the VIN value is most important come inspection time.
old n'slow, I am not sure you posted the issue you are having that arrived at a suspect ECU? What codes brought you to your conclusion? Just curious since I have chased down a few ECU related issues, and neither wound up being the ECU, even after installing a new ECU to find this out. Yes I love to waste money on new parts I don't need, so take any advice I give with a grain of salt LOL
if you guys were asking about a 2009, i could answer this for you. But I can't say definitively for the EtecII..
I don't know ever scanner out there. But I have never found an actually vin on the outside of an ECU or in the code when plugged in.
I know some VAG cars might have that in the immo code. But those cars you need to keep the ecu, key/column, and the speedo cluster together or the car won't start.
Rabbit, FWIW, the VIN is coded in the Aveo ECM's, (as it is supposed to be in all eOBD cars) just request mode 09, and 02 is the VIN request, both of our 06's have the VIN value coded in them. I have used an OBD app called 'OBD2007' and it will read the VIN and display it if you don't mess around with direct J1979 requests. Also when I went to the smog shop they read the VIN off the ECU, and made sure it matched the VIN on the car, (apparently this is a requirement to 'pass') so I have gathered that having it coded to the correct VIN is a benefit. As always your mileage may vary. Other states may not be VIN Nazi's like California, so it may not matter in some cases.
Many might ask, so why can't a DIY'er just change the VIN value in the ECU? Or do a crank relearn? This is due to a seed/key 'security' algorithm, that for whatever reason locks the owner/DIYer out of advanced '$AE' OBD commands. i.e. changing the VIN. It is still a 'to-do' on my list of hobby hacking activities to brute force the key in a 'good known' Aveo ECU, so I can unlock it, and find out if it resembles other ECU's I am more familiar with, if for anything, to gain a better understanding of the PCM. Now that I have a spare TCU, ECU and a CANBUS interface/shield rigged up on an Arduino I hope to explore this area more in the near future, but I have to square away some coding time to make any progress on the key. and far as I know, this is the only reason one need's the GM tech2 scanner, as it has the algorithm math built in, and apparently GM is pretty tight lipped about the formula for sake of the cash cow this has created.
that interesting, as l look it up, I guess its time to upgrade my scanner. I knew it was accessible on my vagcom, but I had not seen it on my other scanner. I guess I will check with our scanner at work and see what i can find. Its newer, but if it reads vins, i don't know.
BTW, in my research i found the info on recoding vins in the ecu..
Yeah I don't keep up on OBD tools myself. Im too cheap. I was just exiting the auto service sector shortly before the tech2 arrived, but I have kept up on SAE standards over the years to know where to look for info in the unit itself, and the protocols used. Any tool will be severely limited due to an IP (intellectual property) pissing contest between GM and the industry that has been going on for decades. Greed is apparently a contagious character flaw that prevents any real progress by the people.
O6T200 asked what leads me to believe it's the ECU . Back about 2 months ago the check engine light came on . It read bad #1 bank O2 sensor & water temp too low . Since then changed #1 Bank O2 sensor with an AC Delco sensor and the #2 O2 sensor with a universal ( NTK ??? ) sensor . 174K miles so I changed both . The O2 sensor code went away .
Changed the thermostat & the water temp sending unit in back of block . My Actron scanner says ECU was reading 189 degrees water temp but after repeated resets check engine light keeps coming back on . RUNS GREAT SINCE # 1 O2 SENSOR WAS CHANGED . The problem is our Emissions test is due this month otherwise I would ignore the light .
Are you seeing the P0120 code at all? If my memory serves me, this is the code for 'low coolant temp'. I fixed this on my LS by installing a warmer thermostat. Turned out the beck arnley t-stat that was marked '189' only got up to around 180-189, and this threw the P0120 until I put in a t-stat marked '195' that was a napa brand thermostat, code went away. I think the ECM wants to see temps in the 190+F range, so you are very close. Does your guage tend to wander around 190-195F, or does it hover in the 180-190 range? If you see readings below 190 consistently I know this will throw the code and the MIL light. Seems like splitting hairs but apparently the ECM is picky. This is a cheap fix, so im throwing it out there, just in case that's your culprit. Keep us posted.
It's my daughters car now ( was mine for the first 150K ) so it might take a day or two to check codes again . I goted with it so I finally had her take it to a local garage where it is now sitting . I'll stop over tomorrow morning and tell him what you told me . Like you said a cheap fix & worth a try . Might take awhile but I will let you know . Thank you .
Now I'm wondering if I replaced the thermostat before or after the check engine light . It was early October when this all started .
P.S. I put the same Dorman metal housing thermostat on son's 04 Aveo ( 100K miles) and no problems with temp codes but one might be more " touchy" than the other .
Thermostats aren't reliably exact, and the coolant mixture will marginally effect it as well. Hell, I've bought as many new bad thermostats as I've gotten good ones. Its a good idea to switch it out to a true 195 degree and see if that fixes it. In my experience a bad ECU will not just fault one sensor. Its more likely that you need to end up with an OEM sensor. VW is particularly good at not accepting cheap aftermarket parts.
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