I recently lost 1st and 4th gear in my 94Z A4. I scanned it, and got a DTC 84. I understand that this is supposed to indicate a faulty downshift solenoid. I replaced all the solenoids in the valve body as preventative maintenance while it was apart. It's all back together now and doing the same thing. I am still getting a code 84. Could this be a bad computer/corrupt program? Anyone else had this problem? Any help would be appreciated! Thanks-Ryan

 

Some of the tests involve needing a Tech 1 to signal the solenoid on and off, but there are a few things you can check.

Unplug the wiring harness to the trans and check for 12v on cavity "E" with the key ON. A test light will work, too.

With the harness still off, you can look at the tranny side to see if you "see" the solenoid. Measure resistance on the tranny between cavities "E" and "S". Your result should be 9-14 ohms. That would mean continuity to the solenoid is good. You could test to see if you hear the solenoid click by jumpering 12v to the "E" cavity on the trans and ground to the "S" cavity. Applying and removing the ground (with 12v applied to "E") would simulate the pcm turning the solenoid on and off.

If all that is good, you can check continuity of the harness cavity "S" back to the pcm terminal B13 (at least that is what it is on a 1995 and I think the 1994 is the same). If you had a Tech 1, you could have already proved this was good with a test light.

 

Thanks Rob, I will double check the above.
-Ryan