Hi

Can you guys confirm that the ECM is the black rectangular box left to the battery? Or is it somewhere behind the glove box?

The FSM (section EC) didn't mention anything about that, I'm a little lost.

Thanks

Hi there, I looked and see a picture in the EC chapter. Of course you haven't listed your car year, so I'm not sure I'm looking at the correct one. But, for a 2009 Altima with QR25DE, it shows a nice picture on page EC-34 and yeah, it appears to be a box next to the battery, left when facing the cars front end.

Thanks

I just took a look at it, the part near the battery, it's part # 31036-ZN56A written on it.

And I think that's the TCM, parts.nissanusa.com lists it as "AUTO TRANSMISSION,TRANSAXLE & FITTING - TRANSIMISSIN CONTROL MODULE" (for part code 31036).

I'll look at that page when I get home, but I don't think this is the ECM.

Sorry I forgot the car details: 2009 Altima 2.5 s (I don't live in the US, but I guess the closest thing there is the federal emissions option).


EDIT:
I just took a look at EC-34 and you're right, it clearly says that's the ECM. But the physical part on my car has the TCM part number. Unless both ECM and TCM are on top of each other? I didn't take the part off the car I just looked at the number.

In the FSM, TM-100 shows the location of the TCM. It's left of the battery and I think it's supposed to be above the ECM.

Okay, I got it. I think you'll get it the right one. The tranny controller will have less pins than the ecu. Look at the plugs for clues.

So, um, why are you wanting to locate your ECU (ECM, ECCS, etc.)? Just for peace of mind or is there an underlying issue you're trying to resolve? I ask, because maybe we can help with that.

Thanks for following up. [Wall of text incoming, brace yourself!]

All this started because no one could do the throttle body learn procedure after I cleaned it and after I replaced the TB. It didn't work manually with me and no mechanic could get it to program with their gadgets.
So I drove 400km to the closest dealer with a Nissan Consult III, only to tell the me I need to replace the ECM because it's not working correctly.

I have a few question I would appreciate if you could answer.
1: What do I absolutely must know before buying an installing one myself (Can I start the car before it's programmed by the dealer? Does the dealer typically flash it BEFORE it's installed in the car? What should I look for when buying used ECMs)? ...etc

2: Parts numbers differ, a lot. For example, I couldn't find the part number the dealer gave me online. I mean it exists in obscure websites but that's it (#23710JB51A). The part number I found on the websites I know is this (#23710ZN65A). What's the difference between all these? Or how can I research the difference? Until now, I couldn't.

3: The only reason the dealer told me the ECM has failed is because they couldn't get the Consult to connect, and thus can't do the throttle learn procedure. Is there any steps I could do that they might have missed? Like maybe clean the connections with an electronic parts cleaner? Because the ECM is under the hood I discovered today, not inside the car so it's exposed to everything.

4: I plan to disconnect the ECM just to see the part and serial numbers, if I do that, would it f*** with it's programming? Would the car remote still work? Would the car still crank? (I did leave the car disconnected in the past from the negative battery terminal for hours and it was fine afterwards in that regards).

And any other additional information you think I should know is greatly appreciated.

1. In older cars, the ECM was somewhat generic and would match a specific transmission/ engine combination. In new cars with black box technology, I'm not sure if the ECM is vehicle specific or not. I would imagine not, but I am guessing, so you'll need to come to your own conclusions.

2. You have a car that came in coupe and sedan format, with auto and manual transmissions, with 2.5 and 3.5 liter engines... that alone makes at least 8 different ECM options. Get access to yours and look at the sticker on the side. Look for the large letters/ numbers. Match those and I think you'd be good.

3. I like your thinking. Dealership may not have the time/ budget for additional diagnoses and just says replace it. You, however, maybe have more time to diagnose. Clean up those connections. Try an OBD-2 consult and see what you get. I am guessing that is a different plug and port than the Nissan Consult 3 port, but I do not know that, could be the same plug. Get the FSM and see if there is an additional fuse that is preventing the consult from working. For example, my friends Durango won't throw codes if the cigarette light fuse is blown.

http://www.nicoclub.com/service-manual? ... ma/2009/EC

4. You can unplug it and plug it back in later. Any codes that were stored in there would be deleted, similar to pulling your battery. I actually think your accessories will keep working with the ECM unplugged (like door locks or headlights). Your car will not crank with ECM unplugged. Once plugged back in, all should work fine.

Check out this thread and see if you find anything useful in there:
how-to-info-reset-ecu-pull-codes-reset- ... 25400.html

I got a small update.

The rpm is now back to normal after the engine has reached normal operating temperature, I could barely hear it, all by itself. I didn't do anything at all since posting this thread other than a single oil change (old oil was 20w-50, new 10w-30). Coincidentally, the car slowly fixed itself after the oil change. Coincidence? maybe, I don't know.

Great! I think oil pressure or more specifically oil temperature can affect cold start mode in the ecu, but I'm not sure about it. So, I'm not completely surprised, but I am enlightened a bit. Thanks for posting your results. I hope it runs good for you from now on.