[Ghetto]

I have a 99 Suby with Torque Bind. It Binds with and with out the FWD fuse in. The AT Temp and the FWD lights on the instrument pannel do not light up when the ignition is turned to on. They never light up no matter what, including when the FWD fuse is in place. I checked the bulbs and they were fine. I am just about ready to replace the duty-c and clutch pack, but now I am questioning why those lights are not working at all. TCU?????
What would cause the AT Temp light not to work, besides a blown bulb?

 

[cardoc]

Bad ground in the transmission harness. Namely the one on the valve body.

Loss of ignition circuit to the instrument cluster is also another possibility. They don't light up for a bulb check?

 

[Ghetto]

Bad ground in the transmission harness. Namely the one on the valve body.
Loss of ignition circuit to the instrument cluster is also another possibility. They don't light up for a bulb check?

The AT Oil Temp and FWD lights never light up, not even for bulb check. All other lights do light up for bulb check.
How would I check the ground on the valve body. Would it be visible after dropping the pan?

 

[cardoc]

Yes. It is a black wire bolted to the valve body by one of the screws next to a solenoid. There is a TSB from the earlier models, but not related to bulbs. Give me a minute or so and I'll post up any diagrams I can find related to the bulbs.

 

[cardoc]

Okay, here you go. You can see in the diagram the bulb circuits. You may want to check the signals from the TCM. Also check the grounds on the firewall and under the dash at the kick panel.

 

[plain OM]

I'd focus on checking the bulbs themselves.

The AT Oil Temp and FWD bulbs are both supplied by the same 12 V as most other warning lights in the combination meter, so if the others come on during the bulb check, the supply is good.

The two lights are controlled by different circuits in the TCM. While it's possible that there's a common element to both (such as a ground) I would make sure the bulbs are good before looking elsewhere.

Incidentally, if the TCM has detected a problem in the AWD control area, such as an open circuit in the duty C solenoid connection (which could cause the torque bind symptom), the FWD fuse override, apparently, is disabled. There was a thread here some time ago where there was a similar problem, but all the warning lights worked. When the FWD fuse was installed, the FWD bulb did not come on. Consequently, installing the FWD fuse in this case probably would not turn on the FWD light even if the bulb was good.

But both lights should come on during the bulb check.

 

[canubaru]

before i dropped the pan, i would unplug the TCU to see if that causes the AT Temp light to come on. it probably will have no effect but it is easy to try.

 

[plain OM]

Yes, probably will have no effect because the TCM, according to the wiring diagram, completes the ground side circuit for the two lights. So with the connector removed, for sure there's no grounding through the TCM.

I guess another way might be to disconnect the harness at the TCM, then using the wiring diagram, find the related pins going to the two bulbs, and either measure for voltage there with the key at On, or ground those pins with the key at On. In the first case if the bulbs are good, there would be 12 V, but the bulbs would still be off; in the second case, if the bulbs are good, they would light. This might be easier than taking down the combination meter to remove and test the bulbs themselves, but that might depend on how accessible the TCM connector is and whether the particular pins in the connector are reasonably easy, and safe, to connect to. The diagrams that cardoc attached have the related info.

But we're on the same page -- best to verify the bulbs at the outset.

 

[Ghetto]

The bulbs were working. I checked yesterday.
I found that the wire from the TCM to the AT Temp Light was severed. I re-attached and now I have new problems.
FWD light does not come on at bulb check when FWD fuse is out. When fuse is in, FWD Light lights up for only 1 second on bulb check then goes out and stays out when engine is on. I am sure that the Duty C is not functioning, so this behavior seems like it may be normal. I do wonder about the FWD Light only staying on for 1 second on bulb check though. The ABS light stays on for 2 seconds during bulb check.
The AT Oil Temp light seems to function correctly now, however it is desperately trying to tell me something. The AT light goes on and stays on when the Ign is turned to on. It stays on until a few seconds after the engine is started. After I reconnected the TCM, the first time I started the car, the light went out and stayed out. After turning the car off and then restarting the AT light blinks non-stop.
ie; Reset TCM - Start car - AT light off - start car again - AT light blinks continuously.
I am having a horrible time trying to find out how to retrieve the TCM codes on this car. I have found the 2 black wires, and I think I have found the connector to plug 1 of the black wires in to, but it only has 4 wires and I am not sure what terminal to connect it to.

 

[nipper]

I think we are giving the car too much credit for being overly complicated.

the FWD fuse only sends a signal to the TCU to hold open the solenoid and illuminate the FWD bulb.

If the TCU fails for some reason you can have a non fundtioning AWD system, it would be stuck in 4wd as the default mode is 4wd. Why I have no idea.

FWD and ATF lights do not come on during bulb check.

The ATF light blinking is telling you there is a major fault, maybe a bad TCU or something else. Usually it blinks 16 times then stops.

Someone here will have the procedure for pulling the codes.

 

[Ghetto]

I found the secret hand shake. I think things may be operating corectly. I was concerned about the AT light blinking continiously, rather than 16 times, but I am suspecting that this is normal for this TCU. I am getting a code for the Duty C as I suspected. Well...Now to replace that.

 

[Ghetto]

I replaced the duty c. The drive plates and gears all looked great. No more Torque Bind and lights function normally.
Thanks for all of the help.:29:

 

[dxevo]

I have a 98 Outback and having a similar problem. I hope someone can help me out. I have noticed mild binding but want to get it before it gets worse, I have AT temp light flashing 16 times at startup and have tried the fuse in the FWD but still noticed the problem I have been trying different versions of the secret handshake but cant seem the get anything. Will someone please helping me out with what the right steps for the handshake on my year. From reading here I have determined that I will have to replace the duty c and the clutches but still interested on getting the codes from the handshake.

Ghetto, can you please let me know where you got your parts and the approx price.

Thank you

 

[nipper]

I have never seen the handshake work on cars that were obdII. The only method that works that I know of is by going into the test connector and jumping wires.

 

[plain OM]

No "secret" handshake. It's in the factory service manuals. See: http://www.subaruoutback.org/forums...4-how-read-diagnostic-trouble-codes-dtcs.html

Whether it actually works is another thing . . .

 

[Climber2377]

when i had the problem with torque bind, my fwd light only went on when it was actually in fwd. sometimes it was locked in awd even when i had the fuse in for fwd and the problem persisted. when the clutch pack was actually disengaged the fwd light came on. changing the solenoid was pretty easy. there are great photos and instructions in that thread. good luck

 

[Climber2377]

i bought the solenoid only, the clutch pack probably should have been changed, as there were some slight grooves that were created when it was locked up... i think it was around one hundred dollars or so from the dealer. i also got mine with a technicians discount though. it was a few years back as well.