Flashing power light

[kingbobdole]

So I'm working on a 1990 Legacy with 202k miles on it. It's for work, but the guy keeps having issues with it, and it never acts up for me, well almost never. He brought it in a week ago with a binding when parking/ around corners issue. He had flushed the tranny elsewhere to try and fix it, but to no avail. After a quick diag, I decided on replacing the duty solenoid C in the back of the transmission that controls the 4x4 lock-up. Problem was solved, no issues.

 

He retuned earlier this week for a slight binding when pulling hard cookies and a flashing power light. I drove it and found it would bind and release at full lock only. After reading up some on a technicians "forum" I decided to add some tough guard ATF additive, like a limited slip stuff, but cannot recall what exactly it was. Helped tremendously, car shifted crisper and the locking was gone. I never saw the power light flash.

 

He brought it back toady, power light was flashing 16 times, which isn't a code. Very short flashes, not long ones. He didn't complain about any drivability issues, so I'm assuming there are none.

 

Any ideas?

[Cougar]

The light indicates the power mode for the transmission and it can come on normally when driving up a hill or under rapid acceleration.

 

Here is the "bold print" from the manual.

If this light stays on for about eight seconds or more after the ignition switch has been turned ON when starting the engine, there may be trouble with the automatic transmission control system. Be sure to have it checked at a nearby SUBARU dealer.

[kingbobdole]

I know it comes and goes with acceleration... but when started, it flashes 16 times right after starting... It has a problem, I just don't know what.

[ShawnW]

From 91 FSM in case somebody else has a 90-94 AT code they need to retrieve:

 

EXISTING PROBLEM CHECK PROCEDURE

Move shifter to D and turn manual switch ON.

Turn Ignition switch ON

Move select lever to 3 and turn manual switch OFF

Move select lever to 2 and turn manual switch ON

Move select lever to 1 and turn manual switch OFF

Partially depress accelerator pedal (this turns the idle switch off)

Verify that the light is blinking on the dash. Count like any Subaru trouble code with long/short.

11-duty solenoid A

12 duty solenoid B

13 shift solenoid 3

14 shift solenoid 2

15 shift solenoid 1

21 atf temp sensor

22 atmospheric sensor

23 engine rev signal

24 duty solenoid C

31 throttle sensor

32 vehicle speed sensor 1

33 vehicle speed sensor 2

There is a procedure for previous problem check, it is :

Move lever to 1 and turn manual switch on

Ignition switch on

Move lever to 2 and turn manual switch off

Move select lever to 3 and turn manual switch ON

Move select lever to D and turn manual switch OFF

Partially press accel pedal

Read codes

[OB99W]

[...]He brought it back toady, power light was flashing 16 times, which isn't a code. Very short flashes, not long ones. He didn't complain about any drivability issues, so I'm assuming there are none.

 

Any ideas?

I know it comes and goes with acceleration... but when started, it flashes 16 times right after starting... It has a problem, I just don't know what.

 

You should probably take the car out for a test drive yourself to determine if there are any drivability issues. I'd suggest paying attention in particular to whether there are any harsh shifts or throttle response issues. TPS problems (misadjusted/defective) can cause binding, along with what I just mentioned, but appear to be due to a defect within the trans.

 

The 16 flashes indicate a code for an electrically-related trouble is stored. Shawn has provided the way to retrieve it. Once you have the code it should be a lot easier to determine the next step.

[kingbobdole]

Sorry to abandon my thread.... but I'm back. The reason I didn't test drive it right away is because I ran out of time to do so. I checked the codes and got a fancy 24... Duty Solenoid C, which I had just replaced with a used unit that tested well. To CMA I testing the wring from the TCU to the harness and then pulled the rear housing off again and replaced duty solenoid C with a fancy brand spanking new one with valve body-ness. Double checked the clutches(because the guy keeps asking me about them) then the harness to solenoid wire, and resealed.

 

Cleared out the computer and started it up, same thing. code 24, but the binding seemed worse... maybe just my head. Still with the FWD fuse, binding was gone. After poking around on identfix I decided to ditch the TCU. Got a used one from Super Rupair and installed. Much better. Code is gone and the car doesn't bind anymore...

[OB99W]

TCU problems causing bind are rare (less rare is a bad connection to it), but obviously can exist. Thanks for getting back with the outcome and fix.

[johnceggleston]

glad to hear you found it and fixed it. the bad tcu is the first i've heard of causing TB. sure would be nice if you could test for a bad TCU before you pulled the extention housing.

[Reveeen]

sure would be nice if you could test for a bad TCU

 

My FSM says: "9-15 ohms from pin 3 to ground at the TCU" (the duty C circuit). Next logical step is substitution of a "known good" TCU, then it becomes "time to get dirty".

 

The older (and further down the road) these cars get it becomes more of a crap shoot as to what goes wrong with a specific one.

[OB99W]

[...]The older (and further down the road) these cars get it becomes more of a crap shoot as to what goes wrong with a specific one.

True.

 

The FSM approach to troubleshooting by substitution is fine, up to a point. Unfortunately, having a bunch of spare TCUs (ECUs, etc.) around isn't very practical for many of us; I tend to do exhaustive process of elimination testing (visual, voltage, resistance, ...) before coming to the conclusion that the control electronics is at fault.

[damone]

I will be doing some test wrenching on the duty C at a junkyard. Should I grab the TCU off the junker while I'm at it.

 

I plan to replace the Duty C in my 91' LWagon, but wouldn't hurt to have a spare if it were in fact the TCU.

 

I have TB when the FWD fuse is inserted.

[johnceggleston]

I will be doing some test wrenching on the duty C at a junkyard. Should I grab the TCU off the junker while I'm at it.

 

I plan to replace the Duty C in my 91' LWagon, but wouldn't hurt to have a spare if it were in fact the TCU.

 

I have TB when the FWD fuse is inserted.

it wouldn't hurt. and if you don't need it some one else may.

 

some say which TCU you use does not matter, some say it MAY make a difference. i would suggest you stay as close to your year as possible, and same body style. if you have a wagon get a wagon TCU. it is my opinion that the shift points are programed slightly differently between the two to compensate for weight differences and such.

[idosubaru]

Should I grab the TCU off the junker while I'm at it.

i wouldn't, they very rarely fail. if you're doing a trans swap or if you like having one of everything (like i do), then sure grab it. but otherwise there are far more failure prone items on your car than a TCU.

[kingbobdole]

i wouldn't, they very rarely fail. if you're doing a trans swap or if you like having one of everything (like i do), then sure grab it. but otherwise there are far more failure prone items on your car than a TCU.

+1... TCU failures are rare, but you must replace the TCU if you change the transmission with one of a different TCU type. I put a 1993 tranny into a 1994 and had power light troubles and torque bind... It had come with a TCU, but I had neglected to put it in... After swapping the TCU all problems went away. You just have to check the number on the TCU... no idea what the difference between them is, but I know it makes a difference.

 

On a side note, to test the duty solenoid all you need is a voltage source... hook it up and try and blow through the solenoid. There should be a click as well...

[damone]

Got Duty C outta a junker. Energized it and heard the click. Was able to blow through oil tube while it was energized and afterwards. I might need to try w/o tube in place as I mayhave been blowig through a leak at tube/Duty C connection??????

 

I got air to pass w/ and w/o power to Duty C.

 

Exhaust was already off junker and it only took about 1hr to remove driveline, cross bars, and extension housing.

 

Didn;t get to install on my vehicle (have to order seals), but I did remove the rear driveline and TB is gone. Running in FWD until I get seals and a few hours (a day or two) to remove mine and put used Duty C in.

 

A sping popped out of the housing when we worked it off the alignment pin. Looks like spring goes around a shaft inside the housing.

 

Any advice on putting spring back together?????

 

Chiltons says housing must be removed as an assembly ewith the tranny. Waste of $20.

 

Thanks

D

[johnceggleston]

A sping popped out of the housing when we worked it off the alignment pin. Looks like spring goes around a shaft inside the housing.

D

if this spring has 'hooks' at one or both ends, it is probably off the 'park lock' mechanism. the thing that keeps the car from rolling when in park. it is a surprisingly simple device located low in the trans, visible after removing the extention housing.

 

third row down, far right picture, in the centerof the pic near the bottom, does it look like this?

 

http://smg.photobucket.com/albums/v204/All_talk/Subaru/4EAT/?

[damone]

if this spring has 'hooks' at one or both ends, it is probably off the 'park lock' mechanism. the thing that keeps the car from rolling when in park. it is a surprisingly simple device located low in the trans, visible after removing the extention housing.

 

third row down, far right picture, in the centerof the pic near the bottom, does it look like this?

 

http://smg.photobucket.com/albums/v204/All_talk/Subaru/4EAT/?

 

I'll have to view pix later.

 

It was the only spring in the extension housing. Fell out as we pried the housing off.

 

Thanks.

[jtowner]

From 91 FSM in case somebody else has a 90-94 AT code they need to retrieve:

 

EXISTING PROBLEM CHECK PROCEDURE

Move shifter to D and turn manual switch ON.

Turn Ignition switch ON

Move select lever to 3 and turn manual switch OFF

Move select lever to 2 and turn manual switch ON

Move select lever to 1 and turn manual switch OFF

Partially depress accelerator pedal (this turns the idle switch off)

Verify that the light is blinking on the dash. Count like any Subaru trouble code with long/short.

11-duty solenoid A

12 duty solenoid B

13 shift solenoid 3

14 shift solenoid 2

15 shift solenoid 1

21 atf temp sensor

22 atmospheric sensor

23 engine rev signal

24 duty solenoid C

31 throttle sensor

32 vehicle speed sensor 1

33 vehicle speed sensor 2

There is a procedure for previous problem check, it is :

Move lever to 1 and turn manual switch on

Ignition switch on

Move lever to 2 and turn manual switch off

Move select lever to 3 and turn manual switch ON

Move select lever to D and turn manual switch OFF

Partially press accel pedal

Read codes

 

 

i had 2 quick questions if anyone knows

 

my green power light started flickering and now doesnt turn on so i cant try this test.

 

also would the power light or tcu mess with the cars accelleration? cuz when i turn car on it revs real high like at 2. and when i put in drive it has loss of power and bearly moves. also the shifter is stuck in park.