94 240 conv with AT shift problems

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240ROCKER
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Re: UPDATE: 94 240 conv with AT shift problems (240ROCKER)

Postby 240ROCKER » Fri Mar 11, 2005 5:40 am

Here is a little bit of an update on my quest to find out why our auto tranny's are behaving in this manner.

First off, I removed the kick panel so I could get at the ECU so that I could see if it would give me an error code. It did not. It gave me a code of '55', which means no error.

Next, I went and talked to a auto tranny specialist here and we talked about this shift problem in great detail for over an hour. He was very informative. He seems to think that this is definitely an electrical problem and not a mechanical one because of the fact that it always happens during the first 5 to 10 minutes of a cold start.

He advised me to splice an LED on the wire that goes to the Shift solenoid for D1 to D2 (this is pin 6 of the TCU). I believe the service manual calls it Solenoid "A". Tie the other end of the LED to ground. Make the wires long enough for the LED to be in plain site while driving so you can see it for this test.

When the car is operating correctly, and the car is still in first gear the LED will be 'ON' and when it shifts to second gear, the LED should turn 'OFF'. Now, if the car doesn't shift into second and you are above 37 MPH, look at the LED as it should be off. If the LED is 'ON' at this point, then the TCU is bad. If it is 'OFF'and your car hasn't shifted yet into second, then more than likely you will have a bad shift solenoid for D1 to D2.

I told him that I had read that on other forums that replacing the valve body was a fix that some people had tried and worked. He told me that the reason that was probably a fix is because more than likely, when the valve body was replaced, so was the solenoid because it is attached to the valve body.

The reason that we are seeing this intermittent shift occur during the first to second shift interval is because this solenoid is used more than the other solenoids. However, in time the other gears will more than likely behave in this manner, which means that the other solenoids will eventually go bad too.

I haven't hooked up the LED yet. The TCU is a little bit further up in the dash and so I really haven't had time yet to unbolt it from the frame. I'm doing that this weekend, so when I get the results of the LED test I'll let you know. If the LED is 'OFF' and the car doesn't shift, I'm taking the car to my tranny specialist and he is going to remove the D1 to D2 solenoid and test it in a heat exchanger to see if it is operating properly.

I'll let everyone know as soon as I know...!

240ROCKER


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guyaverage
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Re: UPDATE: 94 240 conv with AT shift problems (240ROCKER)

Postby guyaverage » Fri Mar 11, 2005 10:07 am

^^ Great information, definitely let us know what happens.

2the40
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Re: UPDATE: 94 240 conv with AT shift problems (240ROCKER)

Postby 2the40 » Fri Mar 11, 2005 1:31 pm

240Rocker... you're my favorite.

Great info!

ncaa1969
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Re: UPDATE: 94 240 conv with AT shift problems (240ROCKER)

Postby ncaa1969 » Sat Mar 12, 2005 12:46 pm

240Rocker (and all interested parties....)I set up the LED's as recommended. I actually used two, one for Solenoid "A" and one for Solenoid "B".

At startup from cold, the transmission shifted properly and the LED's behaved properly, that is: A+B lit for first gear, B only for second, none for third, and A only for overdrive.

I stopped and started until it hung up in first gear, staying in first all the way to redline (where I backed off) without shifting. During this hangup, both LED's for A+B stayed lit, indicating that the TCU was telling the transmission to stay in first gear.

Unfortunately the hang up only occured once and the next (and all following) stop and start operations shifted normally and the LED's behaved normally. I intend to try this again tomorrow once everything has cooled down. I would like to replicate the "hang up for a while but then shift" pattern I sometimes get.

But by your mechanic's analysis this would point to a bad TCU.

TCU's sound expensive, so there is one more thing I am checking. The transmission has a fluid temperature sensor in the sump, a resistor whose resistance drops as the fluid temperature rises. I measured the resistance when cold (65 degrees in the garage) and it was 2560 ohms versus the manual's standard of 2500 for 68 degrees. I took another reading when warmed up and got about 600 ohms (no range is given in the service manual). I will try to rig up a way to measure this resistance on the fly so I can watch the multimeter to see if the resistance drops smoothly as the fluid warms up. Not sure what I'm looking for but I would certainly expect the change in resistance to be smooth. We'll see.

I sure would like the temperature sensor to be the culprit since it looks cheaper and is easily changed (drop the pan and it is right there.)

I wish I knew the computer logic (how it integrates throttle position, RPM, fluid temperature, and probably some other inputs) to decide when to deactivate Solenoid "A".

I'll look for your results and report mine when available. But in the meantime we might start searching parts stores and junkyards for replacement TCU's............

240ROCKER
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Re: UPDATE: 94 240 conv with AT shift problems (ncaa1969)

Postby 240ROCKER » Sat Mar 12, 2005 3:32 pm

Hey there ncaa1969,I finally got my LED hooked up this afternoon to the TCU pin 6. Did you have a lot of trouble trying to get at your TCU. The bottom screw was real easy to get, but the top one was behind the Blower Motor Housing. I had a heck of a time trying to get that thing out. I was finally able to loosen up the heater coil housing enough to wedge the Blower Motor Housing out of the way. I haven't has a chance yet to drive it around yet, I'm gonna do that in a few minutes. I'll report back here when I get some data.The fluid temperature sensor is an interesting theory too. I would think that that is a huge delta from 600 ohms to 2.5K. Maybe that could be our problem. I put in some of that tranny additive that is supposed to bring the fluid down about 10° and when I did that, I didn't have any problems for nearly two weeks.Interesting....

240ROCKER

240ROCKER
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Re: UPDATE: 94 240 conv with AT shift problems (240ROCKER)

Postby 240ROCKER » Sat Mar 12, 2005 4:14 pm

Well...I just returned from driving my car for a few miles and guess what happened? My car started doing the intermittent shift from first to second and the LED remained on, which means the tranny didn't get the signal to shift to second gear. I am going to drive it some more tomorrow and see if I can duplicate these results. It looks liike it might be the TCU.

I have read here and on other forums that they changed the TCU out and still had the same problem. I'm wondering if people got confused, and changed out the ECU, thinking that they were changing out the TCU. I know I made that mistake at first when I started looking for pin 6 and realized that the color of wire was not what the service manual indicated. The ECU is the very first box that you see when you remove the passenger side kick panel. The TCU is further up into the firewall behind the blower motor. It ain't no picnic to get out either!!!!! lol

I'll post back again tomorrow after driving it a while.

240ROCKER

ncaa1969
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Re: UPDATE: 94 240 conv with AT shift problems (240ROCKER)

Postby ncaa1969 » Sun Mar 13, 2005 3:26 am

240Rocker,I didn't make the connections at the TCU so I haven't fought with removal yet. I connected all at the terminal connector under the hood (bottom of three connectors by the fuse box).

I took resistance readings on the fluid temperature sensor at hourly intervals as the fluid cooled down. Resistance seemed to climb smoothly back up to 2.5K ohm range. So I'm doubting my hopeful theory of a bad fluid temp sensor.

But.......if the problem develops when the resistance drops to a certain level you could splice in a resistor and keep the signal from ever dropping into that range. Not sure what that would do to shifting patterns however. I'll mull this over some more.........

Of course there is one very easy fix that won't cure the problem but would make it easy to overcome. You could put an interupt switch on the power supply to the TCU. At every hangup just flip the switch on and off and reset the computer. Same cure as turning the engine off and back on but quicker and easier on the starter.

The saga continues.

240ROCKER
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Re: UPDATE: 94 240 conv with AT shift problems (ncaa1969)

Postby 240ROCKER » Thu Mar 24, 2005 2:32 pm

Well...here is an update for everyone on my quest to solve this intermittent transmission problem. First off, it is not the TCU. I was able to buy one that was rebuilt and guaranteed to work and if it didn't I would only be charged a $25 restocking fee. It was a gamble, but I went for it anyway. After I received it, I put in and after afew short minutes the problem reared it's ugly head. Sent it back and got my money back. Next, I took the car to my trusted transmission shop and he told me from the beginning that he really thought that it was electrical and not mechanical. After doing the LED test that I did, this just proved that the transmission isn't getting the command to shift to second. By me putting in a remanufactured TCU that pretty much rules out a bad TCU.

The transmission shop had it for three days tring to get it to act up and of course it didn't. In fact, he said that this tranny is in very good shape to have 149K miles on it. He said that the tranny is shifting great in all gears and that he couldn't detect any malfunction whatsoever and he has been in the business for thirty some odd years and he knows when a tranny is not behaving properly.

He suggested for me to put an LED on the other solenoid as well and see what state it is in when the shift problem occurs. I noticed that ncaa1969 has already done that and he reported that both LED's were on at the same time which means the tranny doesn't know what to do so it stays in 'limp' mode. This is where the tranny will still run but only in first gear. My tranny specialist said that if both LED's were on, than there is some bleed over from one solenoid to another which is caused by one of three things.

First, if when the problem occurs glance at the speedometer and see if there is some erratic movement back and forth of the speedometer needle. If there is erratic back and forth movement then the Speed Sensor is faulty. It is mounted on the side of the tranny. Second, if the speedometer is OK, then there is a wire somewhere in the main harness that has some of its insulation rubbed off and is somehow shorting to ground or a wire that goes to ground is loose. The third thing he said to check is all the interconnects between the TCU, ECU and tranny. It's very possible since these interconnects are right near the battery that there is some corrosion that has gotten inside one of these connectors causing intermittent connection. He suggested pulling them all off one at a time and give them a real good cleaning with contact cleaner.

My tranny specialist told me that he is nearly 100% sure that the tranny itself is just fine and for me to start looking electrically.

I told everyone from the beginning that I was going to find out what was causing this and I'm just about there.

This guy spent nearly four hours with me on this problem the last few days and I asked him how much I owed him for his time and he told me to "put my money away", that he was very happy to help me out as he wants to know what is causing the problem too so that he can file it in his database.

240ROCKER


ncaa1969
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Re: UPDATE: 94 240 conv with AT shift problems (240ROCKER)

Postby ncaa1969 » Fri Mar 25, 2005 1:25 pm

240rocker, Thanks for the update and news that changing the TCU did no good. BTW, having both solenoids on is proper for first gear per the service manual, not a limp mode. A & B on equals first gear, B only equals second, none on equals third and A only equals fourth/overdrive.

I've been monitoring the voltage output of the fluid temperature sensor as the car warms up. The voltage drops normally from 1.6 volts to .48 volts and the hang up in first gear happens when the voltage is in the .75 to .8 volt range. Still no idea what that means, except that the hang up occurs at that voltage signal and accompanying fluid temperature.

I'll try the contact cleaner on all connections. Can't hurt. Might help.

I have no flicker of the speedometer, perhaps ruling out the speed sensor.

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maik21
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Postby maik21 » Sat Mar 26, 2005 6:09 pm

i have the same problem with my automatic transmision (s13) .... my car dont up shift.... i put into the "d" and it run fine, but dont upshift to "2nd" ; and i have to run in 1st near to redline and depress gas and it shift to 3th, but 2nd never work.... i did a tcu diagnostic and the overdrive light told me that the trans is fine. the solenoids a and b are in 24 ohms .... i disconect the trans arnes from the motor bay and put a 0 volts into solenoid a and 10volts into solenoid b, and no changes... i think that something is stuck!!! what i do to resolve this problem?? transmedic ??

NISTECH
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Postby NISTECH » Mon Mar 28, 2005 6:23 pm

maik21 you got something different going on. The rest of you check your ground on the solonoid harness, It may be inside the pan with the solonoid pack. make sure the crimp on the wires is secure and the wires dont move back and forth in the crimp on the lug. If it does ,unbolt it and clean it thouroughly with brake clean ,dry it thouroughly , solider it to the crimp,make sure your solider flows properly into the wire. Rebolt it on reassemble the car and recheck it.

The led on the light only indicates voltage is present on that wire it does not indicate the tcm is not sending a signal. What it means is the load is not being used anywhere else in the circuit. Which could be a poor connection to ground at the solonoids. I am going to take a look at the service manual and see if I can be more specific on the grounds location.

NISTECH
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Postby NISTECH » Mon Mar 28, 2005 6:41 pm

comforimed they are on the solonoid packs in the trans, check both of them , but your solonoid a and b use the same ground and are in a cluster of 3 solonoids all 3 solonoids share the same ground lug.

240ROCKER
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Re: (NISTECH)

Postby 240ROCKER » Tue Mar 29, 2005 10:21 am

NISTECH,Thanks so much for your help on this. Could you please help me to understand by what you meant by the following: "The LED on the light only indicates voltage is present on that wire it does not indicate the tcm is not sending a signal. What it means is the load is not being used anywhere else in the circuit."

Electronics is my background and I don't understand what you are trying to tell me here. Is the tranny looking for a constant voltage to shift or is it looking for some sort of pulse??

Here is my understanding of what the LED I installed on pin 6 of the TCM is telling me. During normal operation, when the tranny is in first gear, the LED is 'ON' and right before it shifts to second the LED turns 'OFF' which tells the 1st to 2nd shift solenoid to shift...right? When my tranny doesn't want to shift to second the LED remains 'ON' which means the 1st to 2nd shift solenoid didn't get the command to shift. Is this a correct assumption on my part?

Now you also said that the load is not being used anywhere else in the circuit. This is the thing I'm having a problem trying to understand what you are saying. Are you saying that if the connection from the solenoid to ground has an intermiitent connection to ground, then it is not completeing the circuit and therefore there is no load because the solenoid circuit to ground is open?

Have you seen this problem before with the intermittent shift on and 240's you have serviced????

This just might be the big break we all have been looking for. I will be dropping the pan in a few days to check my ground out and to solder it.

Thanks again!!!!!!!!240ROCKER

NISTECH
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Postby NISTECH » Tue Mar 29, 2005 4:44 pm

I Have pondered this problem on and off throughout the day. I too have an electronics background before I got into this buisness. I keep analizing the senarios I keep coming to a dead end since the TCM supplies the power to the solonoid rather then Grounding it which is what control units typically do on nissans. I have not seen this problem on the 240s but have replaced solonoid packs for shift related problems on 240s. I brought that potential problem to the table for 2 reasons one is grounds tend to be a fairly common problem with nissans but also based what I told you on the operation of the typical control unit operation with other components on the engine. Hold off on doing this ground repiar/check till I can review the circuit in depth a bit more. I also brought this to the table since a recent bulliten came out on the altima for a ground issue similar to what I mentioned about the ground as it is throwing a solonoid code and causeing a shift problem from 1 to 2.

240ROCKER
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Re: (NISTECH)

Postby 240ROCKER » Wed Mar 30, 2005 4:30 am

It's hard for me to suspect the solenoid being bad because it isn't throwing any error codes back at all. That is why I tend to agree with you NISTECH that I have a ground problem. I just wish I could be sure that is what it is before I have to take the time to drop the pan and valve body to get at the solenoid and the ground terminal. It also makes perfect sense that it's possible that the one wire from the shift solenoid 'A' is not crimped very well in the terminal or the ground terminal is loose. However, if the terminal was loose, I would think I would be having problems with other shifts as well and not just the 1st to 2nd shift.

So can you think of anyway I can verify that this is a grounding issue without going through the labor of dropping the pan and valve body as mentioned previously? Is there something else I can monitor on the TCM perhaps????

Thanks again!240ROCKER

NISTECH
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Postby NISTECH » Wed Mar 30, 2005 4:43 am

I just got out of the service manual and stumbled across somthing I wasnt thinking of could be the problem. For the hell of it reach down by your gas pedal and unplug the kick down switch for a few days and see if your problem is gone. Its an easy test and the connector is easily accessable. I am wondering if it is sending a signal to kick it down when it shouldn't. I will continue to research but stay away from the panthing for the time being cause logically [after deep thought of its operation] it dosent make since that ground is the problem since the TCM supplies the power not the ground.

Have any of you takin it to the dealer and had them pull it up on consult and check for codes in the TCM? its not the same as checking codes in the ECM.

240ROCKER
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Re: (NISTECH)

Postby 240ROCKER » Wed Mar 30, 2005 5:16 am

Yeah...When this problem first started happening a couple of years ago, I immediately took it to a dealer. Of course it wouldn't act up for them and they couldn't find anything wrong, so they suggested a tranny flush. I have since taken it to another foreign car specialist and they couldn't find anything wrong either.

I will remove the kick-down switch and try that. Regarding your comment about the solenoid being controlled by the power signal from the TCM. If the solenoids ground was not a good connection, as you previously stated, then the solenoid will not shift because the circuit to ground isn't completed and therefore you would have an open circuit. Meaning that the tranny wouldn't even see the solenoid. Right???

This is why I still think that the ground issue could be the culprit!!!!What are your thoughts on this?

240ROCKER

Modified by 240ROCKER at 9:39 AM 3/30/2005
Modified by 240ROCKER at 9:43 AM 3/30/2005

NISTECH
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Postby NISTECH » Wed Mar 30, 2005 3:30 pm

the solonoid is always applied when its in 1st gear, when it shifts to second it turns the solonoid off(takes away the supplied voltage. For some reason its not taking away that voltage. I did find a good page in the service manual which lists all the inputs and outputs for the tcm. I need to go through it and see what is the potential problems and what wont effect the shift decision of the TCM. I have not done it yet and might later tonoght as I have to do some karate with my kids tonight. Both of them are goin up in belts tonight.pretty soon they gonna be able to kick my butt...lol

ncaa1969
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Re: (NISTECH)

Postby ncaa1969 » Wed Mar 30, 2005 4:26 pm

NISTECH,Thanks for joining in our quest for a solution to this apparently common problem. We need the help! I disconnected the kick-down switch but it had no affect. The transmission hung up in first gear same as always.

I had suspected the AT fluid temerature sensor, but I monitored it and there was smooth steady change in voltage as the transmission warmed up - matched the service manual range from hot to cold. If it is of any value, the gear hangup always occurred when the voltage across the sensor was about .77 to .8 volts. Just to be sure, I cut the temperature sensor feed to the TCU and substituted a 2.5K ohm resistor so the TCU would think the transmission was still cold. No help - still hungup in first. Did the same with a low resistor to simulate fully warmed up - no help - still hungup at the same 5-7 minutes after a cold start.

Today I hooked my multimeter across the Throttle Position Sensor as soon as the hangup in first gear started. I got some off the wall readings, twice to three times normal. I should have seen about .5 volts at closed throttle but was getting about 1.3V with wide fluctuation. And the meter jumped to over 6 V at 1/4 throttle. It very well could have been due to one or both of my probes being loose. But within minutes I was getting proper readings (.44 V at closed throttle, about 1.0 V at 1/4 throttle) (it is a new TPS that bench-checked fine before installation)

I'll run the TPS test again tomorrow - I have to wait for full cool down.

Thanks again for your help on this. Greg (ncaa1969)

NISTECH
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Postby NISTECH » Wed Mar 30, 2005 6:41 pm

run a wire from the tps tp the inside of the car and watch the voltage changes while your driving and see if it goes hay wire while driving.

Kick down is a negetive then.

NISTECH
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Re: (NISTECH)

Postby NISTECH » Thu Mar 31, 2005 4:14 am

Ok here is a diagram of all the electrical components the TCM uses to control the trans.

There is a test i would like someone to conduct. If you have a multimeter that has AC capabilities I would like you to back probe pin 25 of the TCM. Measure between that terminal and ground. Watch it as you drive the vehicle see if the signal goes haywire or to 0v when it wont shift. This is the revolution sensor for the trans. it is not the revolution sensor for the ECM. This is an AC volts generating sensor. it should climb from 0v it a stop to over one volt at about 19mph and should steadily increase as you drive. You guys are going to have to start testing things till you find the one that is sending an eronious signal. The TPs is still a concern if it in fact is glitching still do the test on that as well.

240ROCKER
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Re: (NISTECH)

Postby 240ROCKER » Thu Mar 31, 2005 4:28 am

Hey NISTECH congrats on your kids karate belt upgrade.

Here is a quick list of things that I have done in the order that I have done them to try to fix what is going on with my tranny, but to no avail.

1. Replace ATF and change filter2. Transmission Flush by the Nissan Dealer3 TPS replacement4. TCM replacement5. Remove kick-down switch

Here is something that someone did to fix their tranny problem and still had the problem!!!!1. Transmission rebuild which included a soleniod pack replacement but did not include a rebuild of the valve body. After the rebuild was completed, it took about a month before the problem started happening again, but it did return.

240ROCKER
Modified by 240ROCKER at 10:45 AM 3/31/2005

NISTECH
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Postby NISTECH » Thu Mar 31, 2005 4:41 am

This is an electrical problem no doubt about it. But tests need to be done on components that effect the TCM's decision to turn off the A solonoid. Either its not seeing the load of the signal when it got it on or its not seeing the appropriate time to shift to 2nd[Throttle input,vehicle speed]

240ROCKER
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Re: (NISTECH)

Postby 240ROCKER » Thu Mar 31, 2005 12:23 pm

Well...I got bored today, so I went to my friendly neighborhood tranny specialist again and I had him drop the pan and we looked at the solenoid pack and the ground terminal for it. Guess what??? The ground terminal harness was already soldered and there wasn't any evidence of a cold solder joint or an intermittent connection. He also had a set of used but good solenoids that we put on as well. After leaving his shop, I drove about five miles down the road and I started having the intermittent shift problem! Ugh!!!!!! At least now we can rule out the solenoids and the ground circuit for them.

NISTECH, I saw your latest reply after I did this, (that's what I get for getting antsy and jumping the gun ) so now I'm going to put a DMM on the revolution sensor on the TCM, as suggested, and see what voltage I get when it starts acting up. Has anyone else had a chance to do this yet??? What else can I possibly monitor NISTECH???? We are running out of things to check!!!!!

240ROCKER

ncaa1969
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Re: (240ROCKER)

Postby ncaa1969 » Thu Mar 31, 2005 2:47 pm

240ROCKER, NISTECH,

I ran the test on my TPS and got normal readings, not the fluctuating ones I saw briefly yesterday - must have been a loose back probe. My cheap DMM doesn't cover AC so I can't run the revolution sensor test.ncaa1969

ncaa1969
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Re: (240ROCKER)

Postby ncaa1969 » Thu Mar 31, 2005 5:53 pm

Found a Multi-meter with AC voltage capability. hooked it up to the Revolution Sensor feed and went for a run. I got no reading throughout the drive on lowest scale of 200V which reads to the tenth of a volt. Triple checked the probes. I did switch to DC volts and read about .24 volts with no change with change in speed.

My manual says to check resistance across the revolution sensor. Manual says normal range is 500 - 650 ohms. Mine reads 860 ohms.

I'll be interested in 240ROCKER's results.

Changing the sensor looks like a chore. Need to support the transmission, drop the rear cross member and lower the transmission "as far as possible" to get access.Greg (ncaa1969)

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Postby NISTECH » Fri Apr 01, 2005 4:10 am

By the way greg I am working out of a 93/94 service manual as its the oldest i have. test procedures may be listed differently in both manuals. go to the self diagnostics section for a trans code for the rev sensor ,that is the test I was having you run. The problem with some of these sensors is the computer only looks for 0v or constant max voltage nothing in between when it decides to set a code. since you "A" resitance it means the TCM sees something and wont throw a code.

NISTECH
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Postby NISTECH » Fri Apr 01, 2005 4:12 am

Also note the terminal orientation on the 2 yrs might be different so take that into account when doing this. you may have to reffrence your manuals for the correct terminal arrangemnet.

ncaa1969
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Re: (NISTECH)

Postby ncaa1969 » Fri Apr 01, 2005 8:23 am

NISTECH,I have a 92 manual and terminal pins are the same.For whatever reason, my self diagnostic test does not work to give me the flickers on the OD on/off light, so I can't read codes to see if it indicates a problem with the revolution sensor. I have not pulled the panel to back probe on the TCU harness, I have been probing under the hood at the connectors by the fuse box. Can I get codes directly off the TCU? If so, how?I'm encouraged by looking at the revolution sensor as the probable culprit here because:1. the resistance reading on mine is out of range.2. no voltage present on terminal 25 during driving.3. My manual include a "Symptoms Table" and the revolution sensor is listed as the third most probable source for not shfting fom 1 to 2, and is listed as the second most probable for "too high a gear change point from 1 to 2"4. It is logical that the TCU would not shift up to second from first if it wasn't "sensing" increasing revolutions as the car accelerated.But I'm reluctant to plunk down the $150 quoted by my local Nissan dealer for a new revolution sensor, without someone else duplicating my findings. Perhaps 240ROCKER will get some similar failure readings on the revolution sensor. In the meantime, I'll call my Nissan parts department and see if they used to same revolution sensor on other Nissan transmissions (to broaden my chances of picking up a low mileage one at a junk yard.)Thanks again for your help and suggestions. Please send me more tasking and I'll try any tests within my ability. Greg

240ROCKER
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Re: (ncaa1969)

Postby 240ROCKER » Fri Apr 01, 2005 10:29 am

Hey guys,I haven't been able to backprobe pin '25' of the TCM yet. I'll be doing that this weekend. However, I did manage to read the resistance rating from pin '1' to pin '2' on the revolutions sensor and I'm getting a reading of 831 ohms. Like your reading Greg, mine is out of tolerance too. I too called my Nissan dealer and he quoted me $143.61 plus 11.49 tax. Geeeesh!!! This thing is expensive. It doesn't look like to bad of a job to replace, but I want to be sure that this out of range resistance reading is indeed stating that this sensor is bad.

I was hoping that my Nissan dealer had one in stock so I could test its resistance but he didn't because this is a part they don't usually stock because he had never had to have one replaced before.

Looking around on this forum and others, I found several threads on some of the Infiniti cars that had this intermittent problem from 1st to 2nd and the fix seemed to be replacing the revolutions sensor.

Does anyone know where we can get discounted Nissan OEM new parts on the web? I have bought some before from some internet dealers, but I can't remember where!

I will do the O/D diagnostics test and I will also do the backprobe on pin '25' of the TCM and let everyone know what I find.

I really think that we are onto something now guys. Could this be the answer we have been looking for......????????????

240ROCKER


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