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1990 Subaru Legacy TCU codes 12 and 24...


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I just found a writeup on how to check your TCU codes via the POWER light and they came back as code 12 and code 24 (duty B and C selenoids). I've been doing some Googling, but I can't find anything that lets me know exactly what they look like or where they are. Anyone?

 

 

Found selenoid C, it's in the tranny. DOH!

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  • 3 weeks later...

OK, I've just done a lot of reading on torque bind and the duty b and c selenoids on the forum. I don't have the shuddering symptoms that people are experiencing due to the duty c selenoid, so I am thinking that the wire may be broken. Is there any particular place that the wire runs that is prone to cause a break or is it all internal?

 

I just put the car up on stands and inserted the FWD fuse, only the front tires turn even if given a lot of pedal.

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you have tranny issues. The duty c solenoid is stuck open, closed, shorted or open. The duty b solenoid operates the lock up torque converter.

You have an issue that needs to be investigated sooner then later.

 

nipper

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The car was dieing at low RPMs and I thought it might be from a faulty sensor so I changed the throttle position sensor today as I had a spare from the wreckers. I took the car for a drive and it didn't die, so I took the plunge and drove the car to work today (50 mile round trip) to see if anything had changed. I noticed a small shudder while doing some turns out of the area and figure I have torque bind, but I am going to be dropping the tranny very soon so I'll look into that at that time. I never noticed the shudder before this. The drive to work is mostly straight highway and I never noticed it again. Although it was 32C outside today, the temperature guage stayed below the halfway mark. Twice it seemed like the transmission went into neutral for a second as the RPMs spiked when I depressed the pedal just before reaching work, but after backing off and then back on it was fine.

 

I started the car about an hour ago to leave work and the POWER light didn't flash to indicate a TCU error code. Huh!!? Oh well, don't look a gift horse in the mouth.

 

I got about 5 minutes away from work when the car died. No warnings, just dies! I pulled over, turned off the key and fired it right back up, this time with the POWER light flashing, and away I went. About 3 miles from home on the highway it died again, this is the first time it has done it on the highway. I punched the throttle pedal a few times and it picked up for a second a couple of times then completely died. Fuel pump dying? I fired it up and got about a mile and it dies again. Pull over, turn off, fire up and away I go again and make it home with no more troubles.

 

There are so many conflicting issues with the car now that I have no idea where to start with the car dieing, but the tranny is at the top of my list. I brought home some large sockets so I can finish dropping the tranny at the wreckers tomorrow. Hopefully nobody has grabbed it as it is sitting there with about 15 minutes of work left to complete the job. The really perplexing thing is that the ECU is throwing no codes at all and I'm not sure how the tranny could be causing the engine to die like that.

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ok we know we have a tranny issue, and the TB will get worse, trust me on this one.

The driveability issues, we need to know if there are any codes, though it sounds just like a bad ignitor.

 

 

nipper

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Your comment about the FWD fuse. The operation sounds normal. With the fuse inserted you only have FWD. So the Duty C solenoid is working.

 

The stalling on the highway....I had similar issues, which turned out to be the MAF sensor. It did not leave a code. Only one of the last times did it leave a code.

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nipper, there are no codes coming from the ECU.

 

Legacy777, I have another MAF sensor I got from the wreckers. I'll put that in as soon as I get a chance and give it a shot. I figured the Duty C was working fine as the rear wheels didn't move at all with the FWD fuse in, but I am still getting a Duty B&C TCU code. I've tried to reset the codes as per:

 

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http://www.surrealmirage.com/subaru/engine.html

 

To completely reset the ECU (TCU as well) you can use one of the following methods. Note: Resetting the ECU does erase the codes in memory. The first method is commonly referred to as the "battery dance". The second method is to remove the EGI/TCU fuse (fuse 14). Both methods essentually do the same thing, the only difference is that the fuse method only works on the first gen legacies, and you don't loose your radio presets. You want to perform both these procedures on a "cold" engine. Leave it sit for a while, or overnight and do it in the morning.

1. Disconnect the negative battery terminal cable for 30-45 minutes. Or pull fuse 14 labeled (EGI/TCU) from the fuse panel at the driver's kick panel for 30-45 minutes.

 

2. Reconnect the negative battery terminal cable, or re-insert fuse 14.

 

3. Turn off all your accessories.

 

4. Start the car, but DO NOT touch the throttle at all.

 

5. Let the car idle for 10-15 minutes, or until the car is at normal operating temperature. Again, do not touch the throttle.

 

6. Turn the ignition key to the "OFF" position. That's it

 

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Unfortunately, the car would only idle for about a minute before dying, so I have no idea if the codes reset or not. Is there another way to reset the codes that doesn't require the vehicle to idle?

 

I'm heading to the wreckers in about 20 minutes to finally finish removing the tranny from the '93 Legacy. I grabbed a few large sockets from work to get the nut off of the end of the front axles, but it's a crazy 33C out there now and I'm not looking forward to this. Farmer's tan, anyone? :D

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Oh, this is just ducky! I get to the wrecking yard where I spent 3 hours on Monday getting the tranny and diff ready to drop and head over to the car. "Hmmm, I don't remember these cars here. Hey, where's the Subby?"

 

BAHHHHH! They crushed the car this morning!!!!!!!!!!!!!!! :(

 

I can get another tranny from a guy just outside of the city who pulls the parts for you, but he wants $800 vs. the $80 if would have cost me for the one today. *sigh*

 

Tires are all equal and inflated properly, what are the odds a tranny flush would help as opposed to tearing it all apart? My only concern is that I am still getting the noise from what I think is a cracked flexplate, which would require me dropping the tranny anyways.

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Your comment about the FWD fuse. The operation sounds normal. With the fuse inserted you only have FWD. So the Duty C solenoid is working.

 

The stalling on the highway....I had similar issues, which turned out to be the MAF sensor. It did not leave a code. Only one of the last times did it leave a code.

 

 

If the Duty C is working, why would it be throwing a code?

Would you happen to have a diagram (or link to one) of where I find the Duty B and how to get at it? I have found one for the Duty C.

 

I installed another MAF sensor and it fired up STRONG and it idles nicely without dying. I haven't taken it out yet as I want to get the selenoid issue fixed first and I am afraid of tearing up my clutches. Just backing out of the driveway now and turning the steering wheel a little bit makes the car shudder.

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If the Duty C is working, why would it be throwing a code?

Would you happen to have a diagram (or link to one) of where I find the Duty B and how to get at it? I have found one for the Duty C.

 

I installed another MAF sensor and it fired up STRONG and it idles nicely without dying. I haven't taken it out yet as I want to get the selenoid issue fixed first and I am afraid of tearing up my clutches. Just backing out of the driveway now and turning the steering wheel a little bit makes the car shudder.

 

 

how do you know its functioning properly. It can be stuck open, shorted, or failed. We know its not failed. We dont know about the others i can send you something but i need your email

 

nipper

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Ok, after reading the following post I decided to hook up my multimeter to the TCU as well to get voltage reading from Duty C:

 

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http://www.ultimatesubaru.org/forum/showthread.php?t=7084&page=2&highlight=duty+b+diagram

 

Ok, here is what I have done. I wired my volt meter positive to #3 (duty soenoid 3) at the TCU & negative to #10 (ground) at the TCU. Here is what I have found. With the fuse out, I start the car & the voltage is about 6volts. By time I get to the corner, the voltage has dropped to .003volts. Essentially 0V. I am getting a lot of torque bind while all this is going on. If I put the fuse in, I get about 11-12volts at startup & it settles doen to 11.6volts as I drive. At this point I get no torque bind. All of a sudden shile I am driving the volts will just drop to .003v. When that happens the bad torque bind comes back. What is going on? Thanks.

 

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The readings I got were from 0V to .15V, so basically nothing is happening. I put the FWD fuse in and the reading never changed at all, still varied from 0V (usually when stopped) to .15V at max, but it usually stayed in the .05-.07V range. I tried corners, different speeds and matted it once to see if it would change. NADA! I also noticed that the shuddering only happens at VERY slow speeds (backing out of the driveway speeds) with the steering wheel turned VERY slightly. Once I turn the wheel (even cranked over all the way doing 360's) past that point everything is very smooth.

 

I hooked it up to the Duty B and started the car, no change at all. It stays at 0V.

 

nipper, my email is Kilroy@telusplanet.net if you have some info you can send me.

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http://www.main.experiencetherave.com:8080/subaru_manual_scans/FSM_Scans/duty_solenoid_b_diag1.jpg

http://www.main.experiencetherave.com:8080/subaru_manual_scans/FSM_Scans/duty_solenoid_b_diag2.jpg

 

additionally

http://www.main.experiencetherave.com:8080/subaru_manual_scans/FSM_Scans/duty_solenoid_c_diag1.jpg

http://www.main.experiencetherave.com:8080/subaru_manual_scans/FSM_Scans/duty_solenoid_c_diag2.jpg

 

As to how to get at it. It is on the valve body. The transmission pan must be removed to get at them. I don't recall if the duty b solenoid is in the upper or lower side of the valve body. If it's on the lower side, it can be removed without dropping the valve body. Otherwise the valve body must be removed.

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http://www.main.experiencetherave.com:8080/subaru_manual_scans/FSM_Scans/duty_solenoid_b_diag1.jpg

http://www.main.experiencetherave.com:8080/subaru_manual_scans/FSM_Scans/duty_solenoid_b_diag2.jpg

 

additionally

http://www.main.experiencetherave.com:8080/subaru_manual_scans/FSM_Scans/duty_solenoid_c_diag1.jpg

http://www.main.experiencetherave.com:8080/subaru_manual_scans/FSM_Scans/duty_solenoid_c_diag2.jpg

 

As to how to get at it. It is on the valve body. The transmission pan must be removed to get at them. I don't recall if the duty b solenoid is in the upper or lower side of the valve body. If it's on the lower side, it can be removed without dropping the valve body. Otherwise the valve body must be removed.

 

Forgive my ignorance, but is the valve body the part on the rear of the transmission that can be removed?

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