Just picked up a 2000 Maxima with the IACV issue. I'd like to repair this ECU rather than replace it. I've found that one of the Mosfet arrays burned up but this ECU is different (earlier?) than some I've seen posted. The chip that blew was the NEC upa1559h. I've gotten my hands on a few but a couple of the traces on the board are completely cooked and I'm not sure exactly where to lay the jumpers. I just need a picture of the backside of the board in this spot if anybody has an ECU laying around

Traces with chip removed
[IMG][/IMG]

 

Your photo shows the engine mount mosfet, not the IACV mosfet, or did you have both blow? Anyway, I've got an '01, so my pics won't help, but most likely you've blown outputs to the connector, so you could check those. Somewhere on this forum there's a connector diagram with the pins labeled so if you dig that up you could see where to probe, or look at the wiring diagram in the FSM. I'd also disconnect the engine mounts so they can't destroy that chip in the future.

 

Hmm I didn't know that was the engine mount mosfet.I'm getting the IACV code plus the idle is all over the place, yet the 2 STA508A mosfets look completely fine. I guess it's possible that the IACV is trashed but didn't short out the Mosfets. Either way since I have it out and have the chip I'd like to fix it, but I do plan on disconnecting the motor mounts anyway.Gonna look for that diagram

 

Yep the IACV mosfet is the one near the connector, the engine mount mosfet is away from the connector near the top edge of the board (with connector facing left). You can disconnect your engine mounts and probe voltages on the 3 pins, only one should have Vbattery, if the others do too then your mount is shorted. I've heard that blowing an engine mount can damage traces to the IACV mosfet, so maybe your IACV mosfet is ok but one or more of the traces are damaged. You can probe those too, a good reference post is the one by nakis: http://forums.maxima.org/6966447-post29.html

 

Actually this ECU doesn't have the Mosfet (STA509A) near the connector that I see blow up in other photos. In that spot there are 2 smaller Mosfets. The 3 Mosfets toward the side in the later ECU all look Like NECs, I have 2 STA508As and the one NEC in the back that blew up.

Can I assume that the harness pins are the same on this ECU? I dont have a FSM or anything. Since these Mosfets seem to be proprietary I don't think theres any datasheets I can look up for them. That's why I'd love to have a picture just to make it easy.

Do you know what voltages are supposed to be present at the connector for the IACV? I'd like to make sure I don't plug it in and blow the new one up

 

My 2001 ECU has the same 3 mosfets you do in the very same location, one NEC uPA1559H and 2 Sanken (SK) STA508A's. However near the connector I also have a Sanken STA509A, that you apparently don't. However since I know the NEC uPA1559H in my ECU isn't for the IACV, I figured it wasn't your IACV chip either. BTW, I should add that of those 3 mosfets, I'm not certain the NEC uPA1559H is for the engine mount (it could be one of the STA508's), however given others have had IACV issues due to an engine mount failure, I surmised your blown chip was the one controlling the engine mounts, but I could be wrong.

Anyway, one way to figure which chip is your IACV mosfet would be to probe continuity from the ECU connector IACV outputs to find out which part it goes to. I think you'll find it's none of those 3 chips, but it would be good to verify just to be sure.

I'm not sure about the pinouts or the voltages, however you can find the 2000 FSM on this website: http://x.nissanhelp.com/forums/Knowl...5#.UZk4n9jRbpE

 

you could try these guys
http://www.avproecm.com/nissan.htm

 

Were you able to resolve this? My 2000 ecu has the same chip fried. I have one on the way, but want to make sure the rest of the board is okay.

 

Re. the FSM, you should be able get it off this site (just search for FSM).

Re. fusing: AVPRO 311-070 replacement for the STA509A Mosfet is available from AVPRO (see the post by “ManualMaxima” org user). AVPRO will repair your ECU for $250 (with AVPRO fused part) or $190 (with original STA509A Mosfet part). See http://www.avproecm.com/ .

Last month, I talked to Nick at Avpro, he said they would charge me $150 to upgrade my undamaged ECU. (I would have to ship it to them). Alternately, they would ship me their modules for $100. I would have to unsolder the STA509A’s and solder in the AVPRO part; it seems that this is a nontrivial soldering job ... Re. a broken ECU, they will fix it for $250.

Also, note that some ECU-repair companies are not to be trusted: Circuit Medics (definitely not), not sure about others ...