2005 Saturn Ion 2 Issues
 

Hey everyone. I recently bought a 2005 Saturn Ion 2 from a friend with 150k miles on it. I will be giving this car to my 16 yo daughter for her first car. The car has the 2.2 engine and runs great. But it does have a couple issues I cannot figure out without spending hundreds of dollars at a dealership.

About every 50 miles, I keep getting the check engine lights, code P2138, and the car goes into limp mode. The code is for the Accelerator Position Sensor, but the previous owner replace it 5k miles ago. So what else could this code be for?

Also, the transmission randomly decides to shift really hard. Especially going from park to drive and from 1st to 2nd. What's really weird is, if I pull over, shut the car off, wait 10 seconds, start the car again, the hard shifting goes away. I have already changed the trans fluid and getting no error codes for the transmission.

Any ideas of what is going on?

When you changed the fluid, I'm guessing you also changed the filter, right? If not, I'd try that. I'm not familiar with the Ion so don't know what to say about the code you have. Maybe try cleaning the throttle body and running a fuel injector cleaner such as Techron through a tank or two of gas.

I would find what the specific circumstances are that have to occur to set that code amd backtrack from there. I have no Ion experience, but others here are quite the opposite. SOmething may be "fouling" the sensor, might be a poor electrical connection, could be a cheap aftermarket part that doesn't remain within saturn specs as it ages. Just a few "shot in the dark" guesses" for starters.

Could also be simply defective. If it was from autozone, I wouldn't be the least bit surprised.

Thanks for your responses. I did change the trans filter when I changed the fluid. Although I did not do a complete flush and the old trans fluid is pretty brown and worn. I also did take off the throttle body and cleaned it since it was pretty gummed up. Definitely made start up and acceleration a lot better.

I only have the receipt of the repair from the previous owner. I do not know what brand Accelerateor Position Sensor they used.

I was told by one shop the code P2138 can also be trans related, but he is the only one who told me that. All other info I get says only the Accelator Position Sensor.

assume the previous owner bought a cheap part or the shop that worked on it used a cheap part and buy a known good part like NAPA or GM and also the TPS does give a signal back to the computer which does control trans shifting points and harshness

Is it possible that the car needs to re-learn the accelerator position sensor? If it was recently changed, this may be the culprit... I've seen a couple Nissans do just that...

This is what I am afraid of. The dealership wants $150 to flash the computer. Is there any cheaper way?

Find a mechanic with a nice scanner... Most of those can flash the PCM and have it relearn the various sensors on the car... Almost guaranteed to be cheaper than the dealer...

I did some searching for you...

Try the throttle re-learn outlined above, as well as cleaning the throttle body, and MAF sensor...

They say when you key the ignition on,(engine off) the throttle plate should snap closed, open to about 10%, and then snap closed again... Turn the key on for 30 sec without starting the engine to get this "self calibration"... You might also check for linear travel... Basically, take off the intake tube, leaving the MAF connected, turn the key on, and have somebody slowly move the accelerator to the floor and back... You should see a corresponding movement of the throttle plate...

Thanks for the suggestions guys. I take the car into the dealership today to get the 3 recalls done. Once I get it back I will try the relearn procedure and checking the throttle body function.

There is also a sensor on the transmission (cant remember the name of it), that when it goes out, it causes hard shifting. Only issue is, the tranny needs to be dropped to get to it.

Transmission
 

Hey Beater, welcome to the forum! Please let us know if that relearn procedure works. There may also be a an adjustment to set the voltage of the sensor at closed throttle to 0.5 volts, not sure about your Ion. This may have nothing to do with your random trans. shift issues and harsh engagements. If you are checking codes with a code reader, it may not pull up trans codes. Sometimes the trans. controller will send a P0700 code to the eng. computer to let you know there are codes stored in the trans. controller. The computer is called a PCM (powertrain control module) but inside that module there is a separate controller for the transmission. In the old days, Dodge had two separate controllers, but since they work so close together, and share most of the data, it was more cost effective to combine the two controllers into one unit. With a scanner, not a code reader, you will need to access the transmission side and check for codes, current and history codes. I would imagine you will find a slip code, or a circuit code malfunction. When the trans. controllers sees a slip, based on rpm, input and output speeds, etc., the controller will boost line pressure to compensate for the slippage, to prevent further damage. That's why shutting of the key resets the trans. adapts, and it starts looking at data again. If it gets too bad, it will go into limp mode, usually second gear starts from a stop (no power on take off) and won't shift at all. Top speed of about 40 mph. The harsh engagements could be due to the TPS, or say...idle set too high, like a vacuum leak at the intake manifold. And erratic TPS data can effect shifting, but if turning the key off allows the trans. to start shifting normally again, you may have something else going on besides the TPS. I think Best to address the TPS, or APPS first, and go from there...

There IS a temperature sensor for the trans fluid. It looks a LOT like the ECTS. It's mounted on the front of the trans, under the ECTS as a matter of fact. A defective ECTS can and has caused a multitude of problems with the S series cars. DO NOT get one from Autovancerileynapa. Get one along with the pigtail (if you decide to replace them) from a Saturn friendly GM dealership. You want brass tipped, not resin.

I have yet to find one. I have 2 on the main highway by my house.
One told me my 03 is to old to work on, the other told me they didn't know Saturns were GMs.

Trans. Diag.
 

What??? Two GM Dealerships told you that, Goaliemo? Were you trying to get a temp. sensor, or have it diagnosed?

If it was the later, you can take your vehicle to any reputable repair shop. Now I'm not talking about Scooters Garage, Firestone or Wall Mart either, haha. Any good shop can check your vehicle for codes, and/or have the data for your sensors scanned. If they find a problem, you can order the part yourself from the Dealership, if they can still get it, or tell the shop service writer you want OEM (original equipment manufacturer) parts, or sensor installed. Most shops would rather use OEM parts, but usually with the customer, it's all about the cost of the part. OEM parts are most often more expensive than the aftermarket one's.

You can, if you like, Google shop's in your area, and read the reviews of past customers. When you find a shop, call them and see what they charge to read engine AND transmission codes. Then go from there. Just because they read the codes, or even do a diagnosis, that doesn't mean you have to have the repair done there too, if it is something you can do yourself. Yes, of course you could throw a part at it, like a TTS (Transmission Temp. Sensor) or an Engine coolant temp. sensor and it could very well fix the problem. Without a proper diagnosis, you may just be throwing money away that you could have spent to find the real problem in the first place...In my opinion.

In all my experience, I have never seen a bad temp. sensor (eng. or trans.) cause harsh transmission engagements from park to drive or reverse unless the engine idle speed is over 1,000 rpm's. A bad temp sensor will effect shift quality, but won't boost line pressure like a slip code, or electrical circuit code will...causing harsh engagements.

If you decide to have the codes read, let us know what they are. Perhaps you won't need a data scan for diagnosis. If there are no codes in the engine or transmission, you will most likely need some diagnostics performed.

Believe it or not, Scott, the early S series cars had a TAAT4 transmission that wasn't exactly the best on the market. A defective ECTS could and did cause shift problems with the trans. That along with a poorly designed valve body sent quite a few to the junkyard years ahead of their time. It's too bad too, because you can find replacement valve bodies online that take care of the issue. I did that with one of my coupes!

Taat4???
 

Hey there Charlie, thanks for the reply to my post! As you know, I'm new here and certainly not here to step on anyone's toes. You are correct Sir, the old TAAT's did have a host of issues with temp sensors, PRNDL switches, harsh delayed reverse engagements, EPC solenoids, poor line pressure, etc. I believe Billy stated his vehicle was a 2005 Saturn Ion 2, with a 2.2L. I'm pretty sure that is a 4T45E trans, not a TAAT4.

indeed

S car does not equal ION, and the trannys are of course different.
Let's get back on track.
-------------------------------

Any luck with the relearn, Beater?

Doh! I forgot about the trans change, Scott. Thanks for pointing that one out!

Beater?

Ok sorry for being away for so long. Life got in the way lol

So I finally got around to checking things out. Since the code was for the Accelerator Sensor, I looked through all the maintenance receipts kept in the glove box. The previous owner replaced the Accelerator Sensor about a year ago according to maintanence records. So I got under the dash to check things out. To my surprise, I found the mechanic had cut the old harness out and ran new wire from the Accelerator Sensor connector to the connector at the ECU and used crimped wire connectors. Wow! Right!? So I cut out all the crimped connections and soldered the wires together and covered with shrink tubing. Pics are below. So now only time will tell if it throws the code again. It happens around every 50-75 miles.

Now back to the tranny. It still does the hard shifting from time to time. I did change the fluid and filter a while back and it still persists. I have read all your posts and thank you for the replies. I will start looking at sensors for the tranny that I can replace without dropping the tranny........yet. I will start with the temperature sensor. The only code I get is P2138. When that code is thrown, the car immediately goes into limp mode. The code says it's for the Accelerator Sensor, but I've had 1 mechanic tell me it can also refer to the transmission sensors.

Attachment 1602

Attachment 1603

Even the insulation on some wires were bad. This work is unreal!
Attachment 1604

That last photo clearly shows bare wire. If that sucker was touching anything metal, it could have been grounding out. Nice job on the repair. If you're going to do it, don't half ass it, do it right the first time is my motto.

sad.

Keep us updated

Hey Beater, good job rooting out that wiring issue! Solder and heat shrink is the best repair possible! You never want to add resistance to any circuit that is monitored by the PCM, ECU or any type of module, you're just asking for problems down the road! Is there any way that you can pull up a wiring schematic and find out exactly what that exposed wire was, I'm sure it went from the APPS (accelerator pedal position sensor) to the PCM, (power-train control module) but what is it exactly...supply voltage, reference voltage, return signal, etc? It is quite possible that the short, if shorted to ground, may have damaged the PCM or APPS. On drive-by-wire systems (no accelerator cable) any codes in that system will cause fail safe / Limp-Mode operation. If the only code you have now is P2138, I would focus on that first. It very well could be a transmission issue, but if the code is for a APPS malfunction, that code will put the trans. in Limp Mode as a result, not necessarily because the trans is at fault. The transmission has to know what you're doing with the accelerator, so it knows when to up and down shift. Without that signal, it doesn't have enough information or feedback to know what to do. I will try to look into that code when I have time, we are quite busy at work now, so it may take a day or two. In the meantime, try to find out what that wire went to. I know all the wires appear to be the same color, but if you can pull up a connector view of the wiring harness in an on-line shop manual or Mitchell, you can find out the pin location, and what it does. It is also quite possible, with all the wires being the same color, there may be something cross wired. I would also check all the wires from the APPS back to the PCM and make sure they all go to the correct pin locations. Please let us know what you find, and we'll go from there. I think you're very close to getting this issue nailed down!

Yes all the messed up wires were for the APPS. One by one I cut out the crimped connectors and used good solder and shrink tubes them. I've gone 50 miles tonight and still no P2138 code which is good, but it has gone up to 75 miles before being thrown.

The trans is still doing the hard shifts. But as usual, I pull over, shut car off, then restart and it is fine again. This has to be a sensor, at least, but no code is thrown for any trans sensor. Could it be the Automatic Trans Control Module?

YES!!!!!
That is what I was thinking of!
Still need to drop the tranny to swap it though.

But isn't that located inside the center console?

GM 4T45E Trans.
 

http://www.redlineforums.com/forums/..._componets.gifHey Beater, to answer your question, I highly doubt it is a PCM issue. I worked for Aamco Trans for 5 years, and Certified Transmission for 10 years as a Diagnostician. There is no trans control module on your make and model. Everything concerning the eng. and trans is controlled by the PCM. The PCM is not inside the trans, it's either under the hood, or under the dash, maybe center console? All the solenoids and pressure sensors are inside the trans side cover by the inner fender. The Trans will have to be removed in order to access any of these solenoids, temp sensor, pressure switch assembly, or valve body. There is no room to remove the side cover with the trans in the vehicle. The input and output speed sensors are external.

Please read my reply again on 4-29, so as not to repeat myself. A simple code reader my not pick up trans codes, you will need a scanner to access trans data and codes.

Again, if the trans starts shifting hard, then shifts okay for a while after cycling the ignition key, then the PCM is commanding high line pressure...period. Now the question becomes why? If the PCM is seeing a slip, based on eng. RPM, input and output speed sensors, it should set a slip code. If a solenoid is malfunctioning, it should set a circuit failure code, unless a solenoid is mechanically malfunctioning, then it will set a slip code for that too. If the PCM is receiving erratic or wrong information from a sensor, that too could cause the PCM to boost line pressure causing hard shifts, until the next drive cycle. I have seen bad eng. temperature sensors cause this, or stuck open thermostats, where the PCM thinks or sees the engine is still too cold to operate in closed loop, and will drag out the shifts in order to get the eng. up to operating temperature. I have also seen bad Intake Air Temp sensors do the same thing. But, cycling the key won't change sensor data, but it will clear stored transmission cell-tap data with a new drive cycle, causing the trans. to shift normally again, until it sees a problem. Without a scanner, you have no idea what the PCM is seeing...as far as sensor data is concerned.

I really don't believe the PCM is the issue here, either the trans has a slip, a bad solenoid like a pressure solenoid or shift solenoid, or it is receiving erratic or wrong data from a speed sensor, APPS sensor, or some other sensor effecting the trans. Without being able to see scanner data for the transmission, there is no way to properly diagnosis the exact cause of the harsh shifting.

I would recommend taking your Ion to a reputable transmission shop, and spending the $100.00 to have it properly diagnosed. I can't see throwing parts at something, and hopping that fixes it. I also can't see spending 2 or 3K for a rebuilt 4T45E trans, when it could just be a faulty output speed sensor, for instance.

Sorry I can't be of more help, but there is only so much we can do here without getting our hands on the vehicle. Best I can do is tell you how the trans and PCM work together, the logic used by the PCM to control the operation of the trans, and possible causes for the harsh shifting. If I had to guess, I would say something inside the transmission is slipping, and the PCM is boosting line pressure to stop the slip, usually when shifting between gears. If the engine RPM noticeably increases between shifting points, you have a ship, (called a flare) in the world or trans. technicians.

A few more questions: Why did you change the transmission fluid? Was it because of this problem, or did this just start after you changed the fluid? What color was the fluid before you changed it? Did it give off a smell like candles burning, or burnt toast? With 150,000 miles, do you know if the trans fluid had ever been changed before? If this started after the fluid change, what kind of fluid did you put back in...Dextron 6, or something else? What are you checking codes with, a code reader or scanner?

#13: Pressure Sensor Assembly
#305's: Shift Solenoids
#335: Torque Converter Clutch Solenoid
#312: EPC, Electronic Pressure Control Solenoid
#46: Input Speed sensor
#62: Output Speed Sensor

Alpha,

There does appear to be a Transmission Control Module on the Ion automatics.
It's 24226863 for the 2.2L in the 2005 Ion 2 and it is separate from the PCM.

That being said, I do not doubt a single thing you stated with respect to what is likely happening within the transmission, or if it is a result of bogus info from that Accel pedal sensor or something else. You have 15 years hands on experience as a diagnostician and have prob seen pretty much everything imaginable.

However, I think the TCM is in this case being fed all the necessary data from the PCM to do the same decisionmaking that the PCM would do -- or possibly the tranny sensors are connected directly to the TCM thus freeing up the PCU for other tasks.

And I'm happy as hell we have a 15 year auto tranny diag expert among us.

I know your head must be getting big, but please understand that the knowledge you share with us in 15 minutes might take 2 months to sort out on our own. And you explain it with just the right amount of detail (for me, anyway).

Alpha

Wow! Thank you very much for the in depth response. I'm like a sponge and love to learn stuff. I definitely learned a few things from your post. At this point I truly hope it is nothing inside the trans lol.

Doing some research, I do in fact have the 4T45-E Trans. What I was referring to in the center console is the TCU(had to look it up). I do understand it is hard to diagnose problems without the right tools, but I do appreciate all the insight I can get.

So some good news. I have gone 110 miles without the P2138 code being thrown nor the trans shifting hard. So it's either a fluke, or the repair I did is working. And the hard shifting was do to misinformation from the APPS due to the bad wiring. But I think it is still too early to celebrate. If it does throw the code again, I will pony up the money and head off to a dealership to run a full diagnostic.

To answer your questions: I changed the trans oil thinking the hard shifts were happening due to dirty, bad oil. When I drained it, the oil looked to be done. It was brown, and like you said, smelled like burnt candles. There was no record of it ever being changed. I had receipts for oil changes, but nothing on the trans. I replaced what I drained with recommended Dextron VI and replaced the filter. I used a code reader. Not a full scanner.

Thanks Beater for the update, it's great to get feedback! I'M sure you and Derk are right about the TCM or TCU being separate, GM combined the two controllers for many years, (the PMC and TCM or TCU) but with Saturn pretty much doing there own thing, I would not be surprised...good to know, considering the cost for replacing the combined controllers. I do see a lot of manufacturers putting more and more software inside the PCMs, so it stands to reason connecting more and more external modules together with bussed date to free up some room inside the PCMs. Good call, Derf, you are right on target! And, just an FYI, most trans shops recommend NOT changing the trans fluid on anything with over 100K miles, if it has never been touched. It usually causes more problems than it fixes. Trans fluid is high detergent, so it cleans, lubricates and provides hydraulic operation. Sometimes the new slick fluid will cause slipping problems in high mileage units that was not evident with the old degraded fluid. I recommend about every 60K miles, some shops recommend 30K for warranty coverage on rebuilt units. Anyway, thanks Beater, check back soon and let us know how that Ion is doing!

210 miles logged and no P2138 code thrown. I think it's time to celebrate now. Woohoo! Stupid gas station mechanic wiring hack job......GONE! lol

Now the tranny has calmed down quite a bit, but it has acted up once since making my repairs. Could this still possibly be just a dirty trans oil issue causing the trans to overheat? I only changed what was in the pan so there was still 6-7 quarts of really bad fluid in the torque converter. Since it has had time to circulate, would doing another drain be viable?

Alpha ?

Ya I know he said not to change the oil, but it was doing this before I changed the oil and seems to be doing it less after I changed the oil. Just taking a shot in the dark here before really digging into this. I can do just about anything outside of the trans and engine. But when it comes to internals, I know just a little.

Hello Beater, to answer your question: I wouldn't touch it, seriously. I believe that wiring issue with your APPS was causing the majority of your trans problems. If it has only acted up once since the wiring repairs, I would still see if there are any codes stored in the trans controller (TCU) before doing anything else to the trans. You will need a scanner, not a code reader. Some trans shops like Certified Transmission will scan your vehicle for free, call around and see who can pull trans codes, and see what they charge. Some shops will do that for free, just to get you in the door. Make sure you tell them "Trans scanned for codes, not a code reader." I think that would be the next logical step.

A 4T45E life cycle is about 100 to 150,000 miles, give or take depending on abuse and maintenance. If that trans has never been touched, count your blessings, and save your money, you may be at the beginning of the end for that trans. As far as the fluid, don't take my word for it, call a few shops in town, tell them you have a trans with 150,000 miles, and want the trans flushed...see what they say. I would recommend having that trans scanned for codes before doing anything else, that may tell you everything you need to know, especially if there's an P-1811 or equivalent...slip code stored in memory. But, if you had the codes cleared after your APPS wiring repair, the TCU may have to see the fault 3 times to set a code, either way, I would still have it scanned. If there are no codes, drive it until it acts up 3 or 4 more times, and have it scanned again. If the trans went into fail-safe, it set a code in the TCU, either in the "Current Codes" or "History Code" TCU memory. If you do find a code, get back to us and we'll go from there, before having anyone touch it. A second opinion never hurts.

Derk's happy you're here....

Who, me? Happy to be here Derfie Derk...LOL! Sometimes I type too fast, no spell check on names, LOL! You Guys and Gals are the best! ;)

Alright, thanks. That's good to hear I can possibly get it scanned for free. I will wait till it acts up a few times(if any) and go get it scanned.

Update: Good news, 600 miles and no error code. Woohoo! Semi good news, it still does the tranny hard shift, but I've got it pinned down to exactly when it does it. Ya ya, I know to just scan it, but no fun in that! I've learned the normal engine temp on my gauge in the dash. When the engine goes slightly above that temp, it starts to shift hard. Seems like it does this before the fan turns on and the thermostat opens more to cool the engine. So does this in fact sound like the Engine Temp Sensor?

Engine temp, trans problem.
 

Hey Beater, that is good news! Knowing exactly when the trans acts-up is a great start in diagnosing the problem. But, to answer your question, it's hard to say for sure without looking at the temp sensor data. Without knowing what the exact temp is you're talking about, how long it takes to reach that temp, or knowing when your Saturn goes into closed loop, there's just not enough information to work with as far as a temp sensor being the problem.

What I can tell you is it should not take more that 10 to 15 mins for the engine to reach operating temp (closed-loop) with outside temps in the 60's or 70's. Until the engine reaches operating temp, the PCM is in open-loop. Meaning the controllers aren't looking at all the sensors data, like oxygen sensors to control fuel trims (fuel metering) or cell-taps to control shifting, so the PCM and TCU control the engine management and transmission operating functions off basic parameter settings programmed inside the control units. Live data they look at when cold (open loop) is engine temp, intake air temp, engine rpm, vehicle speed, cam and crankshaft sensors (on most vehicles). But like I have said before, if it starts shifting okay after you turn the engine off, then back on again, it sounds to me like the TCU is seeing a problem, perhaps only after the vehicle goes into closed loop, or reaches a certain temp then the TCU is boosting line pressure trying to compensate for the problem or malfunction.

Ya ya I know too, but I'm still not sure why you are unable or unwilling to have the TCU scanned for codes? No hard feelings, but without that information, it's anyone's best guess. You can try a temp. sensor, they do go bad, and cause all kinds of issues, but I seriously doubt that is your problem. The PCM may command the TCU to delay the shifts a little in order to reach operating temp, but not after. If the trans shifts fine when cold, then shifts hard when warmed up, that sounds like a slip problem, sensor or solenoid malfunction to me. Now we know the only time it slips or malfunctions is when it's hot, like perhaps an input speed sensor with high resistance when hot...but that doesn't mean the temp sensor is problem, unless of course, the engine and /or trans are overheating.

Exactly what temp are the fans coming on? To know for sure, I would check that gauge with a scanner to see exactly what the temp sensor is reading when the fans are commanded on, and check the block and head temps with a laser temperature gun to see if the temp sensor is accurate, if you think it's a temp problem, that's the best, most accurate way to know for sure. Dash gauges are not as accurate as a scanner in most cases.

I would still scan the TCU for codes (with a scanner not a code reader) before trying to diagnose everything else under the hood first. Why take a 20 mile trip, when you could get there in 5, what's the fun in that? For us Mechanics, time is money, if the trans is acting up, that's where we start...then backtrack from there, not the other way around. ;) I understand your logic around the temp concern, and obviously there is a correlation, but I believe that is the condition under which the problem exists, not the cause of the exact problem.

Just to clarify, here is an example of cause and condition. A few weeks ago a new customer came into the shop and said he wanted his B1S2 Oxygen Sensor replaced. When I ask him why, he said O' Reilly checked it with a code reader and they said it had a bad Oxygen Sensor. He didn't know what the exact code was, so I scanned it. Sure enough, lean code, Bank 1, Sensor 2. I explained that the O2 sensor was probably alright, and was doing it's job, letting us know that there was an engine problem. Come to find out, he had a vacuum hose that was leaking at the intake manifold. I could have replaced the sensor, but the problem would have still been there. The condition was a check engine light, with an O2 code, no power on acceleration or under load, and sometimes idle was too high...but the cause was a vacuum leak, not the O2 sensor it's self.

In your case, the temp is the condition under which the problem exists, not necessarily the cause of the malfunction. Heat is a major factor in electrical components, if they have a problem (worn or sticking mechanically) heat can increase internal electrical resistance, causing the circuit to draw too many amps. Heat is also a factor in clutch and band applications, as the trans temp increases, the fluid thins out, new or old fluid, makes no difference, but new fluid is slicker, which will cause more slippage in a trans with high mileage. Also, the trans will not adapt, or monitor cell-taps for shift quality until the engine goes into closed loop, again, cause and condition. The TCU and/or PCM is seeing a problem and trying to adapt, or compensate, but that doesn't mean the controllers are at fault, they are doing what they are programmed to do. Boost line pressure if they see any slippage, or fail-safe to second gear in the event of a major failure.