TCU codes and issues

[SiCkSTi04]

I've always had issues with MY91 auto fwd legacy. But now I'm starting to see the bigger picture and actually taking note. Sometimes I turn the car On and see that the "power" light is blinking really really fast and it never goes away while driving.

The tranny is acting really weird when that happens but its random and may go away on the next start up. This is what happens when the "power" light is blinking throughout driving, If I'm driving in "D" the car doesn't seem to want to shift from first gear. Getting the car up to speed gets the RPM's up high like its not shifting, letting off the gas pedal while coasting watching the rpm needle reach down to 1.5 rpm always results in a small jerk and the rpm jumps up to maybe 2.0-2.5 then when it reaches 1.5 it does it again and again until the car isn't rolling anymore. Like i said this could all go away once starting it up again after letting it sit.

Time to check the TCU codes yet? YES! Today I followed Josh's walk through on pulling the codes. He stats two methods "Existing problems" and "previous problems"

Method 1 "Existing problems" - Gives me a non-stop blinking Green "power" light. it's not giving me flashing codes unless that itself is a code of its own.

Method 2 "previous problems" - gives me code 33 Vehicle speed sensor 2. I've searched and found that it's located in the speedometer cluster?

Something to also note, I cant get the "power" light to come on when driving in the "3" "2" or "1" when driving hard. I think it's never came on since owning the car.

If I want to clear the TCU codes would leaving the fuse 14 out be the best way of doing that? This is leaving that either the VSS2 needs to be replaced by the "previous problems" codes stored or that my TCU needs to be replaced by the "Existing problems" non-stop blinking "power" light.

Any help would be great at this point because I really want to get this fixed lol

[Legacy777]

Yes, pull fuse 14, EGI/TCU to reset the ECU & TCU. Once you've done that, verify that there are no codes stored in the TCU's previous problems. Once you've done that, then drive the car and see if the problem still returns.

Have you noticed the speedometer stop working intermittantly?

Regarding the power light coming on during normal driving. It usually takes depressing the accelerator pedal very quickly to engage the "Power" mode and the light to come on.

[SiCkSTi04]

Last night I plugged the fuse 14 back in and went for a drive so I could then run the codes for the TCU. The "Existing problems" and "previous problems" all showed the normal blinking every 1/4 sec. And guess what? My "power" light even kicks On now when in "3/"2"/"1" pressing down on the gas pedal.

Josh I'll report back if that problems comes back. Would a stored 33 code cause my legacy behavior to show out of nowhere? I'm probably going to replace the speedometer cable and speed senor that connects to transmission as it shows very little bouncing when accelerating.

[Legacy777]

Not exactly sure what you're asking here: "Would a stored 33 code cause my legacy behavior to show out of nowhere?"

Can you clarify?

Not having a speed sensor input can kind of cause the ECU & TCU to go batty. I would suggest trying to clean and relube the existing speedo cable if you can. Unless you just want to replace it. The base piece in the transmission will eventually fail at some point, but I'm not sure if you can really predict it.

[SiCkSTi04]

Would a TCU code 33 that was found in the "previous problems" memory cause any future problems to arise? In this cause it was a really fast green "power" light and the symptoms I spoke of which were random and went away every few weeks at a time.

I got a brand new speedo cable and sensor but if cleaning/greasing the ends is all i have to do then I'll do that instead

[Legacy777]

Previous problems shouldn't affect current drivability, but ir probably couldn't hurt to clear the code.

As for the cable....it has to be completely removed from the sheeth and then regreased. If you have the new cable it may be best to just replace the old one as grease can get caked in the housing as well.