ateick

iTrader: (1)

Congrats on the fix. What an ordeal.

Imagine though the amount of people everyday that just say yes to the $2300 misdiagnosed quote and all their hard earned $'s are flushed down the toilet for no reason when all it took was unplugging that mount.

I hope the apologized up and down.

Congrats again.

jontyrees

The $800 was to replace the motor mount, but I told them I just wanted to unplug the existing mount, leave it there, and reset the security system

jjubert

iTrader: (2)

Isn't there something you should do to adjust the electric motor mounts before you disconnect them in order to improve ride comfort? Feel like I should do this before problems like this occur.

Fakie J Farkerton

iTrader: (51)

No.

Montego Murph

iTrader: (1)

He may be very right.

It's my understanding that the mounts go "soft" below 1200 rpm, and "firm" above 1200 rpm.

I remember reading somewhere that when you disconnect the mounts, you should do it while the engine is held at 1500 RPM so that you're removing it in "firm" mode. A little more vibration at stop signs, but overall better while traveling.

Should he go ahead and do this, or is he risking something by plugging the mount back in?

Fakie J Farkerton

iTrader: (51)

dwapenyi

iTrader: (3)

Put in another way:

risk frying the ECU, or live with a little dis-comfort until the motor mount is replaced?

Chances are the mount will be replaced with non-motorized one, so this dis-comfort may be something he will be getting used to.

Also, it looks like the electrical mounts default to firm mode, i.e, with power dis-connected the mounts are firm. The kid's observations bear this out: the car experiences shakiness at low rpms, when the mounts should be soft.

jontyrees

That's how i'm approaching it. I haven't driven it yet to get a feel for how much vibration there is, but i doubt it's significant. Plus, I don't drive it, so what do I care - lol. The manual transmission versions don't have the active mounts - do they vibrate more at low rpm?

Quickywd01

iTrader: (16)

Every noob should read this thread.

dwapenyi

iTrader: (3)

Yup.

gapboi210

I would think the mounts default to soft. Most use metal filings in the hydraulic fluid. Electrical current is applied to cause the shavings to group together making the mount firmer. Remove the power, no voltage, softer mount. From what I understand anyways.

nestorlugo

iTrader: (11)

Huh!



When i removed my center beam the (oem) mount on the rear was completely torn ,the metal in the middle where the screw goes thru fell right off! The only thing i saw was a passage way leading to the bottom of the housing.

Child_uv_KoRn

iTrader: (7)

I can't believe you got that lucky. It must have been a day away from frying the ECU.

jontyrees

Ugh. I declared victory prematurely. Car crapped out again yesterday, exactly the same symptoms. Of course it can never do this in my driveway, it's at my kid's buddy's house, so there's another tow charge coming.


Three thoughts come to mind.
1 - the ECM was damaged, and has finally given up the ghost.
2 - the dealership unplugged only the mount that caused the problem first time around, and the other active mount is now causing the problem
3 - the dealership unplugged the mount, communicated with the ECM, reset the code, and plugged the mount back in.


Options appear to be getting the car home and checking to see that both mounts are unplugged. Pull the ECM to look for signs of damage, (I don't know how to do this yet, but I'm hoping there is a tutorial here somewhere). Replace the ECM - most likely with an aftermarket part, since I've seen people on this forum who did this with no problem, and you can get them for ~$100.


Question is, once you replace with a new ECM, how do you have to reset codes, etc to work with the keys I have? I'm hoping the mobile auto locksmith, who couldn't communicate with the car the first time, will be able to do this as long as the mounts are disconnected.


And I thought we were out of the woods!

dfj240

iTrader: (1)

The new ECU will have to be programmed to your keys and ignition switch. This is typically only possible through the dealer. I don't know of any locksmiths personally that have the equipment or experience to communicate with the car's electronic systems, specifically the NATS.

The possibilities you list are certainly not far off base. Very possible for any of those to be the problem. I hope you can get it tracked down quickly and get it resolved once and for all. If I were a gambling man, my money would probably be on option 3 on your list though.

TexasTex

iTrader: (1)

It's always something it's not, at the dealership.

jontyrees

The plot thickens.....I was able to restart it once I got it home, by turning the key from off to power accessories on, back and fore a couple of times. The Security light by the clock went from solid on to flash, then off, and the car started no problem.


Question is, is this a sign that the ECM is about to give up the ghost, and that I should get another one while I can still drive the car? Do electronic parts like that slowly give up? I'd have expected a more binary situation - alive, then dead, not ailing for a while.


I checked the motor mount lead, and the dealership did leave it disconnected, so that's not causing the problem.

The_Fixer

iTrader: (1)

Have you ever thought that the actual key switch is going bad like in the 4th gens?

maximasicilian123

I read only up to this post. Take ur car somewhere else and don't ever go back there. Sometimes its hard to find a good mechanic but try Google u might find reviews

dwapenyi

iTrader: (3)

The car does have 2 electrical motor mounts, front and back.

dfj240

iTrader: (1)

Your absolute best bet is to pull the ECU and inspect the circuit board for signs of burning, charring, shorting, etc. If you find any such instances, then the ECU needs replacing. Electrical boards are peculiar things, but an electrical board is an electrical board. Have you ever seen a TV that seemed to be temperamental about working or made loud humming noises until it warmed up, etc.? Same idea. The board or it's components have been compromised in one way or another, however there is still enough contact that under the right conditions the board will conduct as normal. Outside of those specific conditions, the board doesn't have the ability to pass the proper current and will fail causing the car to fail to operate.

Long story short, it's not entirely uncommon for electrical components to be in the ailing state for a while. Hell my brother's old B17 Civic had an ECU with a fried diode or capacitor in it, so his car would just shut down randomly. Sometimes it wouldn't start back up for days, other times it would die and then come back before the tach hit 0.

I use the same rules for electrics as I do for women; Don't try to understand them, don't push them when they're at their limit, don't ignore them, and whatever you do, don't tell them that they belong in the kitchen. Not sure how that applies to electrics, but I'll leave that to your good judgment for it's judicious application.

Anyways, beer, rambling, stopping.

TL;DR - Pull ECU, inspect ECU; if bad, replace ECU, get NATS programmed, job done, have beer.

jontyrees

Solid. I've been avoiding the inevitable conclusion that the ECM needs to be replaced, but I think that's the only way to go. More hassle, more expense - and the prospect of another trip to the dealer . I need to grab the part number info for the current ECM, which I understand I can read from the passenger footwell without actually pulling the thing out. There are several used ones on ebay for $65-$100, so I'll most likely grab one of those. Or would a new aftermarket one be better? I REALLY don't want to pay $700-$800 for a remanufactured one from Nissan, or $1,000+ for a new OEM board. If it were a new car, it might be different, but we're talking a 12yr old ride that we got for less than $5k.


So I'm thinking it goes something like:
- get matching used ECM
- pull existing ecm from bracket, and drive to dealership with it hanging on the floor, switch new one in in their parking lot
- ask dealership to flash the new ecm to work with the keys I have


Sound right?

Quickywd01

iTrader: (16)

You're getting smart. Sounds about right to me.

jontyrees

Just pulled the trigger and bought a used ECM from Ebay. I couldn't read the part number form the passenger side footwell, but had a brainwave and stuck my cell phone in there a snapped a few pictures, until I got one that included the PN. Had to zoom in on it, but came up with A56-T68 ZP7 2322


Ebay search revealed several pulled units with A56-T68 ZP7, but with varying 4 digits after that. I don't think that's significant, probably just the manufacturing run. I bought one for $99.50 shipped with the suffix 2222. It was the cleanest looking in the pictures, pristine in fact, and was pulled from an Infiniti I35. Who knows, maybe an I35 has an easier life than a Maxima, lives in a garage, gets serviced regularly, etc.


When I do the switch, I'll take some pictures and post them here.


On another note, I'm getting conflicting opinions on whether a 2002 Maxima has active motor mounts front and back, or just front. How can I confirm?

dwapenyi

iTrader: (3)

Download your FSM here;

Index of /FSMs/Nissan/Maxima

I realize when I commented before I was looking at the 2003 Maxima. 02 and 03 should be physically exactly the same pretty much, but who knows?

Assuming so, you should find what you're looking for in the EC section, page 712 or thereabouts.

jontyrees

Thanks - great link! The 2002 manual talks about Front and Rear Electronic Controlled Engine Mounts, so It must have both. It also mentions testing their operation without a Consult II device by revving the engine past 1k rpm with the transmission in D and disocnnecting the harness. If the car vibrates more when it returns to idle, the mount was working. This suggests that it would have been better to rev the engine to set the mounts on "hard" before disconnecting. It wasn't an option for me, since the malfunctioning mount tripped the security immobilizer, and we had to disconnect the mount just to get the code cleared. I don't want to reconnect it long enough to raise the revs up in case it fries the ecm entirely. Now my question is, where is the connector for the rear mount? I'd like to unhook that one too.

Long term, since I ordered a replacement used ECM, I may get replacement front and rear active mounts - they're pretty cheap on ebay - I think around $150 for the set of 4 including active F and R. Depends how difficult they are to install.

jontyrees

Found it:

http://ww2.justanswer.com/uploads/fi...ount_plugs.jpg

dwapenyi

iTrader: (3)

Dont know if it makes a difference but that pic is a 5th gen as opposed to your 5.5 gen.

jontyrees

I saw that - it's actually an I30 Infiniti. I'll have to check the car when I get home, but according to the website that pic came from, the mount connectors are the same. We'll see. The more I read about it, I think if I do end up replacing the mounts, I'll go with non-active. A little vibration is the tradeoff for more peace of mind.

TexasTex

iTrader: (1)

You're in Austin? My stomping grounds.

Were you on the mile?

The_Fixer

iTrader: (1)

You dont need electric mounts and 95-03 mounts are all the same

jontyrees

Yep - the old South Point Nissan has recently become Clay Cooley Nissan.

If that avatar is new, I'm guessing you're a Spurs fan?

My next move is to see how hard it is to unscrew the ECM from the bracket behind the center stack. There's not a whole lot of space back there to get a screwdriver at it. Looks like a socket might work though - seems like the screws are hex shaped. I had a quick go at unhooking the electrical harness from the ECM, and that sucker was on there pretty good. It didn't just glide off.

jontyrees

That's what I figured. Only thing that might make me replace the current mounts is if they were in the soft state when the connector was unplugged. If I do replace, I'll go with non-active.

TexasTex

iTrader: (1)

Wow, I remember South Point. It's Clay Cooley now huh?

The Avatar is new, fitting of the crying that went on last night! DIE HARD SPURS FAN. I grew up in Dripping/Driftwood area and have been going o Spurs games since the Alamo Dome and D-Rob was a kid, hence my Spurs tattoo when I was 18!

I took a peek behind my EMC when I bought this car, it shouldn't be too difficult to get behind there.

cornholio

iTrader: (1)

get a small right angle screwdriver if your ratchet doesnt make it. similar to this one:


you can find one at lowes/home depot (probably autozone, aa, etc). not too hard to get it with that.

be careful putting the harness back on the ecm, don't force the locking clip too much or it will shatter (i found out the hard way lol)

jontyrees

Thanks - good advice.

Child_uv_KoRn

iTrader: (7)

gear wrench

TexasTex

iTrader: (1)

Agree. I have no idea how I worked on anything prior to these little beauties...

Nopike

iTrader: (2)

Good advice.

I only wish you the best but other than the dealer mentioning it there is no reason to think the ECU is the cause of your problem. The dealers don't know what the hell they are doing half the time any ways. Try the easy cheap stuff first.

In your first post you stated. "The car was running just fine, but started to be reluctant to start. Engine turning over just fine, so battery and starter were fine, just wouldn't catch. After being like this for a day or two, it completely failed to start. Engine still cranking just fine, but no start."

So the engine is cranking fine means you are missing fuel or spark. I would still consider a starter. Much easier to change than the ECU and if it does not fix your problem you just take it back. I'm not suggesting you just throw parts at the problem. But if I really do not have a handle on the problem, which appears to be the case here, I focus on cheap and easy stuff. Ignition switch, starter, make sure I'm getting fuel and spark and work from there.

The ECU is generally a pretty reliable part of the car. I'm just trying to help, don't want to see you go to all of the trouble of replacing the ECU and still have no luck.

If you can get the ECU tested/replaced easily as one poster suggested go for it. Otherwise consider the items I mentioned first.

maxiiiboy

Since the car is cranking fine, it's not the starter. You are either not getting spark, or no fuel, or both. I would start by confirming that you are getting spark.