Hi,
I have a 1999 Nissan Altima SE, 4 cyl. auto. The ECM is not sending the transmission the "down-shift" signal and was told by the dealership that I need to replace my ECM for $600. I've located a used one with the identical part numbers on it. Does anyone know if I can just slap that into my car and possibly have the car run right. I've been told that some of these things require special programming specific to the car it is in. My car doesn't have an ignition key with a "Smart Chip" in it so I don't know that I'll need to have this unit programmed. I guess if it is "pre-programmed, then I should be OK"
thanks in advance for any feedback!
kidakat
Replacing an ECM ECU
That wasn't it (Replacing an ECM ECU)
Hi again,Thanks for the response. You clearly know much more about this than the local Nissan dealership. I found a used ECM out of an identical low miles wreck off eBay for $25 so I snagged it. When the unit arrived, I installed it and all symptoms are the same.
Here's what's happening:1. When I start the car, the O/D light flashes several times2. The Check Engine light is on3. When driving, the engine doesn't seem to down shift when I step on the accelerator (for example: when passing)
When I first brought the car in to the Nissan dealership for the "Check Engine Light," they scanned it with their system and said it returned a diag code of 1705 and that the problem was a bad "Throttle Position Sensor." After they replaced that, the Idiot light came back on and the O/D light stopped flashing when I started the car. I brought it back to them and they said, "Oh, there must have been two codes in there, it looks like you need a new ECM" I of course, almost fell over when they quoted me a price on having that done. So I decided to try to take a stab at it myself. I'm not 100% sure of what the used ECM is telling me, but it seems like it's doing essentially the same thing that the other one was doing, except for the O/D light is now flashing sometimes again when I start the car (not every time). My gut feeling is that there was nothing wrong with the ECM. Do I need to have this one re-programmed? I had the boys down at AutoZone re-scan it with thier cheapo diag tool and it returned code 1705 even after replacing with the used ECM.
You suggested the TCM or TPS as the possible problem, from what I've been reading in other posts, the TCM seems like a good candidate. Can you tell me where TCM and TPS are located in a '99 Altima. Are there any other model cars that I could pull from in order to get a used one?
thanks so much for your help,
kidakat
Here's what's happening:1. When I start the car, the O/D light flashes several times2. The Check Engine light is on3. When driving, the engine doesn't seem to down shift when I step on the accelerator (for example: when passing)
When I first brought the car in to the Nissan dealership for the "Check Engine Light," they scanned it with their system and said it returned a diag code of 1705 and that the problem was a bad "Throttle Position Sensor." After they replaced that, the Idiot light came back on and the O/D light stopped flashing when I started the car. I brought it back to them and they said, "Oh, there must have been two codes in there, it looks like you need a new ECM" I of course, almost fell over when they quoted me a price on having that done. So I decided to try to take a stab at it myself. I'm not 100% sure of what the used ECM is telling me, but it seems like it's doing essentially the same thing that the other one was doing, except for the O/D light is now flashing sometimes again when I start the car (not every time). My gut feeling is that there was nothing wrong with the ECM. Do I need to have this one re-programmed? I had the boys down at AutoZone re-scan it with thier cheapo diag tool and it returned code 1705 even after replacing with the used ECM.
You suggested the TCM or TPS as the possible problem, from what I've been reading in other posts, the TCM seems like a good candidate. Can you tell me where TCM and TPS are located in a '99 Altima. Are there any other model cars that I could pull from in order to get a used one?
thanks so much for your help,
kidakat
You have already replaced the TPS[throttle position sensor] P1705 is if i remember correctly torq convertor solonoid. This mean the TCM did not see the proper trans response when it sent a signal to operate the solonoid. Now this could either be The solonoid or failure in trans hydrolic control. There was a tsb on the solonoid pack having problems on earlier model altimas but I do not know for sure if it applied to your yr. The fact that your O/D light flashes upon start up says its an electrical malfunction. Heres a little something you can do as a basic check. pull your air filter assembly out of the car [top and bottom] at the front drivers side of the trans you will see a group of wires coming out of it there.[ you will need to look down below the battery tray from the air box locatin and infront of the motor mount. When you find that group of wires follow them where they lead to 2 or 3 multi wire connectors make sure all those connectors are clean and free of corrosion in thier terminal pin area. If they are make sure they are completely seated and latched when connected. If that group of wires appears ok I would lean toward your problem being internal in the trans,something with the solonoid pack itself.
Note the reason your ECM displays a check engine light is because the TCM is in constant comunication with the ECM for primarily emissions reasons It throws codes related to trans if the failure could ultimatly effect emissions negetively. A Trans not going into lock up could cause a car to emit more emissions dure to the constant higher RPM. This is why the code is displayed in the ECM.
Note the reason your ECM displays a check engine light is because the TCM is in constant comunication with the ECM for primarily emissions reasons It throws codes related to trans if the failure could ultimatly effect emissions negetively. A Trans not going into lock up could cause a car to emit more emissions dure to the constant higher RPM. This is why the code is displayed in the ECM.
I went ahead and spent the time to check every multi-wire electrical connector with wires coming from or going to the transmission. All seemed nice and clean with the rubber o-ring in tact.You had mentioned that if the wiring connectors didn't prove to be a trouble point, it was likely the "Solenoid Pack." Would that require removal of the transmission? I'm fairly adept in the shop with old school technologies (for example I converted my 1984 Jeep CJ-7 from an In-Line 6 cyl 258 ford engine with auto transmission to a Chevy 327 with a 4 speed manual transmission) any chance I could tackle it myself? I wouldn't be surprised if I don't have some special tools required to do transmission work. I've found Nissan parts sales places that sell the "AT solenoid" for $158. Could that possibly be all I need?If it's not something that an amature like myself could take on, do you have any words of advise as to how I can locate a qualified person to do the work? I can't stand paying some guy to take guesses at parts which he thinks may need replacing.
thanks again for your guidance!
kidakat
thanks again for your guidance!
kidakat
well honesty here I am technically taking a guess at whats wrong with your car as well since I am not actually testing your car. but it is my best educated guess from what I have dealt with on nissans I work on daily. The solonoid pack is very easy to replace your self. You need to pull the trans pan then lower the valve body. The most important part of this job is that you only remove the bolts neccesary to drop the vlave body. There are twice as many bolts in the valve body then need to be removed to lower the valve body out. In the factory service manual there is a map to which bolts you need to remove. I usually make a photo copy of that image and zoom it up on a copy machine and tape it to the bumper of the car so I can reffer to it while removing the 10 or 12 bolts that hold the valve body in. once you drop the valve body its a simple swap out of the solonoid pack.
I can appreciate your concern about giving technical advise when you haven't had a chance to put your hands on the broken machine. I'm a computer network technician and I do lot's of technical support and I understand how hard it can be to see through another person's eyes when troubleshooting any problem (car or computer).
Is there any chance that that page from the Factory Service Manual is available on-line somewhere? Thanks again, you've already given me more help then I ever imagined I'd get.
Is there any chance that that page from the Factory Service Manual is available on-line somewhere? Thanks again, you've already given me more help then I ever imagined I'd get.
Here it is, Note all the bolts that are marked are the ones you need to remove to drop the valve body, the ones that are not marked do not. be alert to where the springs go when you drop it down. they are different sizes and must go back in where they came out. watch for orings above the valve body make sure they stay put during the repair,and most impotantly work clean,do not allow any foriegn debris get back in there when going back together if you are going to wipe anything down use a cloth baby diaper not the red mechanics rags. once you have printed this diagram out let me know,the way its set up now its a serious BW gobbler so I am going to delete it or at least reduce its size once you have it.
As I'm prepairing to do this I was going through all the symptoms again in my head and I realized that I left out one thing that may be an additional indicator for problem determination.
When the transmission is shifting into O/D, it is sometimes a hard shift if the driveline is under power. It'll almost throw you back in your seat and there is a bit of a "thud" if it shifts into O/D while you're still on the throttle.
However, if after climbing a hill, I take my foot off the accelerator for a second and let it go into O/D by using the switch, it will shift nice and smooth.
Does this still sound like it could be the AT soleniod pack?
thanks
When the transmission is shifting into O/D, it is sometimes a hard shift if the driveline is under power. It'll almost throw you back in your seat and there is a bit of a "thud" if it shifts into O/D while you're still on the throttle.
However, if after climbing a hill, I take my foot off the accelerator for a second and let it go into O/D by using the switch, it will shift nice and smooth.
Does this still sound like it could be the AT soleniod pack?
thanks
It definitly could be since the solonoid pack controls line pressure througout the trans. The key here is the OD lite flashing on startup that points derectly at an electrical problem as the trans [other then the pump] is not doing anything that would allow the TCM to diagnose its mechanical functions. As I said before I would also lean to a TCM since it controls the operation of the electronic portion of the TCM but I have not seen any failures like yours that pointed to the TCM it was always the solonoid pack as the problem.Experiance with these transmissions is the reason I am thinking its the solonoid pack rather then the TCM at this point.
Picking up on an old issue with my Transmission
Nistech,If you're still out there, thanks so much for the time you spent helping me with this back in the summer. I've been away from working on this problem for about 6 months due to a move and change of jobs. The problem still exists and I'm going to work on it some more. You stated in your last post that you believe that the problem is most likely the solonoid pack but could also be the TCM.
The techs at the local Nissan dealership (which I'm wondering about), told me after the last visit that they thought it was the TCM. I also got the feeling that they didn't want to work on this car any more because it keeps coming back in the day after they work on it. Being of that, I'm probably going to try to do the work myself now. I'm thinking I should start with which ever is the simpler procedure (TCM or Solenoid pack).
You've already given me detailed instructions about the solenoid pack and it sounds like there is some room for error on a job like that one. I'm wondering where the TCM is and if that's not a better place for me to start. Is the TCM a part internal to the transmission or is it easy to get to like the ECM?
thanks again!
kidakat
The techs at the local Nissan dealership (which I'm wondering about), told me after the last visit that they thought it was the TCM. I also got the feeling that they didn't want to work on this car any more because it keeps coming back in the day after they work on it. Being of that, I'm probably going to try to do the work myself now. I'm thinking I should start with which ever is the simpler procedure (TCM or Solenoid pack).
You've already given me detailed instructions about the solenoid pack and it sounds like there is some room for error on a job like that one. I'm wondering where the TCM is and if that's not a better place for me to start. Is the TCM a part internal to the transmission or is it easy to get to like the ECM?
thanks again!
kidakat