Subaru Outback Forums banner

1 - 11 of 11 Posts

·
Registered
Joined
·
7 Posts
Discussion Starter #1
Hello all,

I purchased my first Subaru(03 legacy wagon 4EAT with 166000 miles, has about 180000 now) last February and I love the car. After searching through the forums here I figured I'd start my own thread and maybe get some pointers/advice from the experts here on an Issue I've been having lately. Sometimes while driving, the AT Oil Temp light begins flashing and doesn't stop until the car is turned off. This in turn makes the Check Engine light come on as well. Typically it only seems to happen when it is very hot or very cold outside. Yesterday was in the 30s all day and the AT Oil Temp began flashing on my way to work, and on my way home, today is in the 50s and it didn't do it this morning. Also, I think I've began to notice some correlation between the AT oil temp light flashing and the air controls inside the car. Is this possible?

The first time this happened was late summer/ early fall so I took my car to a friend and plugged up the OBD2 scanner. The code it gave was P0743 Torque Converter Clutch Solenoid Circuit Electrical. Since I hadn't really noticed any issues with the AT I decided to just clear it and see if it comes back up.... and it has. I know there are quite a few forums here with vehicles throwing the same code, however none seem to really be quite the same as mine.

The car runs and drives great, there is nothing I can notice about it's performance that would help pinpoint what particularly is going on. I've kept up with general engine maintenance and all fluid levels are good, AT fluid looks clean.

I think my first plan of attack this weekend is going to be testing AT wiring and hopefully that will help solve the problem without dropping the pan. If that doesn't work I think Ill have to drop pan and inspect wiring/ solenoids/ sensors there.
If that doesn't work I really don't know what to do. I don't particularly want to take it in somewhere, I enjoy doing stuff like this myself. However I think there may come a point when it goes beyond my capabilities and would be best to just take it to a mechanic.

With that being said, does anyone have any advice to give this novice? Pointers? Things to consider/ look out for? Really anything would help and be much appreciated.

Please let me know what ya'll think, and let me know if there is any info that I left out that would help. I look forward to hearing your responses

Thanks,
Kevin
 

·
Premium Member
2001 VDC/SC One of a Kind
Joined
·
12,847 Posts
First, I'd check the battery and the cabling. A weak battery, one that is not providing ample ampere output, not necessarily voltage, will cause problems, especially with an automatic transmission. Since you also posted that the AC controls act up, it's probably related to a poor battery and bad ground cables.

You would have to have a meter that can measure ampere output with the battery cold and then check conductance through the cables, the negative from the battery to the lug by the starter and the positive from the battery to fuse box, battery to starter and alternator to the fuse box. On the main cables you don't want more than .2 ohms resistance. Then check the body grounds, once you get the main ground good, and you should not have more than .4 ohms resistance between the battery negative post and the ground lugs on the engine and body. There's a main ground lug on the intake manifold, 2 actually bolted down side by side, one by the ABS module, one by the fuse box, 2 on the firewall, one that runs from the top of the transmission by the pitch stop mount and connects to the the top bracket for the pitch stop on the firewall. Then you have a cable under the car that connects the heads to the frame rail, 2 on the lower radiator bracket for the lights, horn, etc.

Beyond that, the TCC applies at speeds over 28 mph and light throttle in 4th. It also engages when engine load levels and in 4th when cruising. Without TCC lockup the engine speed stays high and the torque converter continues to slip and increases the fluid temperature. So more fuel consumption and shorter fluid life. Once the code sets the TCM stops trying to engage the clutch until the next key cycle. This helps to keep the clutch from burning up. It may already be burned up and you may be looking at a new torque converter to fix it. But check the electricity supply and cables first.

There's also a ground wire on the valve body that can come loose and this can effect the TCC solenoid as well as the shift solenoids for the gear train and the center diff clutch. If/when you pull the pan, it's the black wire and just bolts to the bottom of the body.
 

·
Registered
Joined
·
7 Posts
Discussion Starter #3
Update,
I couldn’t locate any issues with power, battery looked great never ended up dropping pan I just started using the gas a little more conservatively and the light hasn’t really showed back up until recently. I think the problem may lie in an issue with the drive belt on the P/S and alternator. Lately at slow speeds with wheel turned in either direction close to it’s limit, the power steering acts up and you can hear and feel the belt squealing and skipping momentarily until the wheel is straightened back out. Car still drives and handles great until parking the car. New belt and power steering flush is going to happen when I get off work today. I was curious on your thoughts, could this skipping/power steering belt issue be causing a problem with the power distributed to all the components that run off of alternator? (More specifically, this strange at oil temp flashing that’s going on?) I really appreciate your response to my last post and apologize for such a delayed response. I’m going back out to sea next month so work has been hectic prepping and getting the ship ready for sea. Please let me know if I left any informative details out that would help. I look forward to hearing from you.
Kevin
 

·
Registered
Joined
·
7 Posts
Discussion Starter #5
Note taken,
Replaced p/s belt (was super cracked and brittle) fluid looked great still bright red and transparent so I didn’t bother with changing. Car issue with the belt skip and chirp is gone so once again I cleared the P0743 code to see if that would fix my problem and it’s back once again. Still can’t find any sort of power issues from battery, but I must admit I am pretty ignorant when it comes to electrical work so any more info you give is an amazing help. I guess I’m just gonna have to dive in and drain ATF fluid and check the clutch selenoid that lives in the pan( please correct me if I’m wrong). After that, I’m pretty much out of ideas. I reckon possibly replacing torque converter all together? Thanks again I really appreciate you.
Kevin
 

·
Premium Member
2001 VDC/SC One of a Kind
Joined
·
12,847 Posts
You can check it from the connector. Here's a pic. You'll check resistance on the power side of the solenoid to ground, terminals 13 and 16 of the trans side of the connector. Should be between 10-17 ohms. If it's not, then you know you have to drop the pan and most likely replace the solenoid
TCC Pinout.png
 

·
Registered
Joined
·
7 Posts
Discussion Starter #7
You can check it from the connector. Here's a pic. You'll check resistance on the power side of the solenoid to ground, terminals 13 and 16 of the trans side of the connector. Should be between 10-17 ohms. If it's not, then you know you have to drop the pan and most likely replace the solenoid View attachment 479542
Did a atf fluid change and dropped the pan before I saw you’re reply. Previous owner said it was last changed at 150,000 (has 180,000 now) and there’s no telling if it was just a fluid change or if they also replaced filter as well. From what I could gather it was due for one and Weather was awesome so I figured what the ****. Oil was pretty nasty but not terrible compared to others I’ve seen. There was some metal accumulation at bottom of pan and around magnet and the filter seemed oddly heavy even after it was drained, like it had accumulated quite a bit of debris.( maybe it hadn’t been changed during last atf fluid change?) Checked all the solenoids after I let it drip for a while. Resistance on every solenoid was up to specs. Popped out the TCC solenoid just to inspect it a little further and couldn’t find any issue with it so I put it back in it’s place. Replaced strainer and got the pan spotless. I think the most tedious process of this whole thing was getting all the **** RTV silicone off of the pan, housing, and all the little bolts holding the two together. That **** was everywhere. Replaced RTV with a regular gasket that came In a kit with the new strainer.( used a little RTV to tac it in place) bolted pan back in place and replaced fluid. Car is running better than ever, notice running at lower RPMs. Nothing crazy but around 26-2700 at 70mph whereas before it was around 3000 and the TV lock up is working wonderfully . Also when I turned the key immediately following refilling AT with fluid I noticed that it cleared the check engine light that kept popping up after flashing AT oil temp. (P0743) Been driving for 3 days now and the issue hasn’t came up again so I’m hopeful the AT service I did helped solve the problem. My thought process is maybe that dirty fluid/ tiny metal particles getting in solenoid possibly causing it to short and throw that code shutting down lock up? I will update in a week or two or if that code comes back sooner. I’m gonna test the connector like you suggested when I get home from work today just to see if maybe there is an issue in the wiring between TCM and solenoids but as long as everything is functioning properly I don’t think I will see any abnormality in the wiring. Am I correct to assume this? Anyways I really appreciate you input/guidance on this. If you ever find yourself in the Hampton Roads area, let me know. I owe you a beer.
Thanks again,
Kevin
 

·
Premium Member
2001 VDC/SC One of a Kind
Joined
·
12,847 Posts
Great job.

Keep an eye on that trans pan gasket. Subaru uses the Fuji Bond for a reason. It seals better and lasts longer, especially with vibration and heat. Ultra Grey is the next best thing.

It may be that the connector for the TCC solenoid was loose just enough to keep it from functioning. Could've been metal/debris disrupting the fluid flow. By chance, did you notice if the ground wire bolt was loose or not? That would be the black wire coming off the solenoid wiring harness at the rearward side of the valve body.
 

·
Registered
Joined
·
7 Posts
Discussion Starter #9
Great job.

Keep an eye on that trans pan gasket. Subaru uses the Fuji Bond for a reason. It seals better and lasts longer, especially with vibration and heat. Ultra Grey is the next best thing.

It may be that the connector for the TCC solenoid was loose just enough to keep it from functioning. Could've been metal/debris disrupting the fluid flow. By chance, did you notice if the ground wire bolt was loose or not? That would be the black wire coming off the solenoid wiring harness at the rearward side of the valve body.
cardoc,
Sorry again for delayed response, note taken on Fuji bond in the future. I was on the fence about whether to use RTV or just the pan gasket that came with the strainer kit and opted for the simpler option.( really hoping it doesn’t bite me in the ass later down the road) Have been checking for any signs of leaks pretty much daily and am happy to say there are no signs of ATF leakage anywhere. Also happy to report that the AT has continued to preform exceptionally and that pain in the ass AT OIL TEMP flashing code has not returned!!!! Started seeing a difference in my fuel economy as well, now getting quite a few more miles per gas fill up. I reckon this is thanks in big part to the TC lock up finally functioning properly. Really happy to get that hiccup behind me and learned quite a bit in the process.
Focusing now on replacing front+rear brakes(calipers/rotors/pads/the whole 9 yards), as well as front and rear hubs and wheel bearings by the end of the month as I will be going back out to sea and will be gone for about 8 months. Got all the parts I ordered early in the week. Refurbished caliper/mount assembly from autozone. Front wheel hubs/bearings and rear hub/bearing assembly’s from 1aauto (Thoughts on this? Am I a cheap ass for trying to save a little money instead of just getting them through Subaru? Subaru just wanted so **** much. I spent almost as much on all these parts already as I did on the price of the vehicle lol). Also got rotors, inner and outer front wheel bearing gaskets, new snap rings for front wheel bearings, Misc bolts, and new front window gusset assemblies (Finally had enough of the loud ass wind noise and having to basically holler to have a conversation with the windows up) through the local Subaru dealership. Went to replace all braking components last night, wanted to get the whole project done after work but I just didn’t have the time to dive in to bearings+hubs. So I opted for just changing calipers pads and rotors, and checking wheel bearings+ hubs to see if they really even need to be replaced or if they seemed good enough to just let ride and save the project for when I get home in November. Started W/front wheels, F/R wasn’t too bad( rusted to **** but came off the knuckle without too much effort. F/L was a little more difficult caliper, slide ins and accompanying bolts were all seized up and getting them out took more time than I would have liked. Old calipers out/ hanging in wheel well from struts old rusty brackets removed F/L rotor took a couple taps with a rubber mallet to come free from hub, F/R came off with ease. Removed dust cover/cleaned thoroughly inspected cleaned off hubs and steering knuckle. ( knuckle is looking pretty bad, quite a bit of corrosion. Planning on replacing this and some suspension components when I get home at the end of the year.) Wheel bearings aren’t terrible but there is a little bit of noise I noticed when spinning hubs, I’m on the fence about replacing bearing prior to going out to sea. Might just leave them so I have a project when I get home. Went to put new rotors in place and apparently ordered the wrong ones :). (I’m an idiot, luckily the local dealership is cool and are delivering the correct ones to me to at work today to swap with wrong ones I purchased). So I just put the old rotors back on and installed new calipers Torqued everything to spec ( Am I anal for following every torque specs there was? Pops started to talk **** seeing me torque every bolt to spec. My thought process is there is a torque spec for a reason, and if you have the ability to do so why not follow them?). Was really happy with how smooth that went, which was in big thanks to forums here and just reading about things to look out for. Wheels back on ( another thing I need to replace) dropped front end torqued lugs to spec, picked up back end wheels off. R/L caliper bracket was a nightmare, bolts wouldn’t budge tried P/B blast then tried heating with torch. Ended up stripping bolt head, and cutting bracket off of rear arm ( I believe this is correct name) it bolted to. R/R caliper and bracket came off w/o issue, as well as both rear rotors. Much less Corrosion present in rear and hubs spun super smooth with no noise. Definitely something weird going on with rear suspension though looks like something is missing/ broke off ( hard to explain I’ll post some pics when I get off work.) New rotors and calipers installed wheels back on lowered back down. Replaced gusset assemblies for both front windows, (ahhhhh it’s bliss, finally I can hear myself think and have normal voice decibel conversations without the cacophony of jet engine like air noise coming through my windows). Also found some cool yellow fog lights. ( idk why I’ve been wanting these. Don’t know that there’s much functionality to the yellow light, I really just think it looks cool lol) So rotors are being delivered to me today at work, those will be installed when I get home and Ole Blue will be about as good as he’s gonna get while I’m out at sea. Only decision I’m still on the fence about is if I’m gonna pull the hubs and bearings up front before I leave...... Any thoughts comments or concerns would be much appreciated.
Kevin
480210
 

·
Registered
Joined
·
7 Posts
Discussion Starter #10
By chance, did you notice if the ground wire bolt was loose or not? That would be the black wire coming off the solenoid wiring harness at the rearward side of the valve body.
Also forgot to mention, yes cardoc I know which wire you’re speaking of and it was securely fastened, no wiggle room with it or with any wire in pan.
thanks again,
Kevin
 
1 - 11 of 11 Posts
Top