Can a Bad TCU Cause No Shifts??

[SilverstoneXJ]

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'93 Talon
Auto, FWD
1.8L N/T

New to DSM cars, and this forum. I'm trying to figure out why my auto tranny won't shift at all in any gear. Bought the $400 car thinking it just needed a rear main seal, and now found it won't move at all in any gear (yeah, believed the guy saying "It drives great"). Before I pull the tranny for a new one, I want to make sure it's not something electrical or simple.

I tried a test light at the TCU Diagnostic Plug, and didn't get a light on any of the pins. Just wondering if something is up with the TCU.

As far as tranny checks, I have checked the fluid level both with the car off and running. The level doesn't change (drop). Also pulled the dipstick out. Placed my thumb over the dipstick hole, and no suction. Pulled a cooler line off one at a time, and no flow out when running. Sounds like a pump issue, but want to rule out anything else that could be at fault first.

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[SilverstoneXJ]

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I picked up a needle meter tonight for TCU code pulling, since my test light didn't seem to work. Here's the cides that I pulled:



45 - Open-circuited shift control Pressure Control Solenoid valve

47 - Open-circuited torque converter clutch solenoid

41 - Open-circuited shift control solenoid A

43 - Open-circuited shift control solenoid B

83 - Open or Short-circuited Shift Control Solenoid valve A

84 - Open or Short-circuited Shift Control Solenoid valve B





Next, I probed the shift solenoid wires (yellow and orange) with a test light. I can't find where I read how they were supposed to light up, but here's what mine are doing:



L - Yellow Lit; Orange Lit

2 - Yellow Lit; Orange Not

D - Yellow Lit; Orange Not

N - Yellow Lit; Orange Not

R - Yellow Lit; Orange Not

P - Yellow Lit; Orange Not



I'm pretty sure I remember that orange was supposed to light up more than once. The clicking sound is present in all gears except neutral, park, and only for a few seconds in reverse, which I've read is normal. But posting this in case it helps diagnose anything. Monday, I'm planning on pulling a tranny from a junkyard car for $70, unless I hear something else.

[sbiggi]

There are two plugs on the tranny that can easily be reversed.
If they are it will go in limp mode which means only 3rd gear when in Drive.

Pretty sure the solenoids make a lot of clicking when the plugs are reversed.


-Seth

[SilverstoneXJ]

There are two plugs on the tranny that can easily be reversed.
If they are it will go in limp mode which means only 3rd gear when in Drive.

Pretty sure the solenoids make a lot of clicking when the plugs are reversed.


-Seth

I wish I had at least 3rd gear. It would be better than nothing. Found out that the '93 year DSMs have to have '93 trannies. J/Y didn't have one for me.
Back to troubleshooting for now. Does anyone know where i can get transmission wiring schematics?
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[Mirage]

Factory Service manual comes to mind...

Every DSM'er should have this for their year car. It's invaluable and by far the best investment for anyone even thinking of digging into their car.

Marcus