New Trans or New ECU

[senrab]

I took my 95 with 193k on it to the dealer to have the codes read and had multiple codes. P0026,0052, 0055, 0070, 0076, 0091, 0094, 0109, 0133.

The day started out with the trans not shifting at all .. stuck in low or 2nd (I wasn't sure 4000 rpm @ 50 mph). I know several of these are tranny codes but lots of other strange things have been happening also. Sometimes the cruise doesn't work, I have to pull down in a lower range then shift back to D to engage the mission, occassionaly the car won't start like the battery is low. I've checked the battery and terminals and everything is good and clean (both times it started in a few minutes). Today I also had the DIC say to "clean the key and wait 3 minutes" (a new one). The dealer told me what some of the codes were but said they couldn't print out a OBD I and some of them didn't matter and were conflicting. Of course they wanted to start right in on it, but I'm not sure they will fix it, and with almost 200k I don't want to put a ton of money in it.
It has been clunking into gear hard like the TSS is bad and I asked them to check the computer TSS rpm vs the tach. They didn't and like all service centers the Technician never talks to you just the desk jockey.
I have reset the check engine light in the past and then the trans would shift to gear smoothly and the upshifts were smooth. When it clunks into gear it also shifts like it has a "shift kit" and grabs hard. Now I can't get it to reset. The ABS TCS lights (P0133) were on till I replaced the fr wheel bearings (I've done both).

Can anyone tell me what the codes are and what sensor is causing it?
Is it possible that my ECU is a flake?
If it is the ECU do I have to get one from an Autobahn model (mine has it)?

[ghutchin]

26 - Throttle Position Switch Circuit Shorted (Low voltage)

52 - DTC 52/109 WILL SET WHEN

* PCM loss of prime power, such as battery.
* PCM loss of long-term memory with ignition "OFF."
* PCM engine running loss of long term memory.
* PCM intermittent loss of prime power.

55 - Closed Throttle Angle Out of Range

70 - Intermittant Throttle Postion Sensor Signal
76 - Transaxle Pressure Control Solenoid Circuit

The pressure control solenoid is a Powertrain Control Module (PCM) controlled device used to regulate transaxle line pressure. The PCM compares Throttle Position (TP) voltage, engine RPM and other inputs to determine the appropriate line pressure for a given load. The PCM will regulate the pressure by applying a varying amperage to the pressure control solenoid. The applied amperage can vary from 0.0 to 1.1 amp. The PCM then monitors the amperage at the return line.

91 - Transaxle part/neutral position switch circuit

94 - Transaxle Shift Solenoid A Ration Problem
This electrical device is used to control fluid flow acting on the 1-2 and 3-4 shift valve. The solenoid is a normally open exhaust valve that is used in conjunction with the "B" solenoid to allow four different shifting combinations. The solenoid is attached to the control valve body within the transaxle. Ignition voltage is supplied directly to the "A" solenoid. The Powertrain Control Module (PCM) controls the solenoid by providing the ground path.

109 - Similar to 52

133 - Loss of ABS/TCS Data
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So what does this all mean...well either something has eaten/cut a bunch of the wires to the transmission, throttle position sensor and ABS/Traction control module or your ECM is failing. Since you have the 52/109 code I would just get a new computer and throw it in and go from there. I've heard of the computers going in these cars. I don't think this is something like a grounding issue to the computer, but who knows. A computer won't set you back much if you buy a used one. I would make sure to check to see if you have the autobahn package. I think that would be the only compatibility issue. They may have not even offered autobahn in 95.

Also the clean key wait three minuntes is a totally separate module from the ECM. You probably need to have your ignition cylinder replaced, and or bypass the passkey system to fix this problem.

[ghutchin]

Okay, you do have autobahn, I think you would need an ECM out of the Autobahn aurora. The trans shift tables would be different since the ratios between the input shafts and drive shafts are different.

[senrab]

Thanks ghutchin,
I appreciate the quick response. I really did think the ECU might be the place to start. As for the wires ... its driven most everyday and hasn't been wrecked, so I don't think mice are working on the wiring.

How do I tell if the computer is for an Autobahn?
Does it have to be a 95 ... will a 96~99 work?

[ghutchin]

It has to be for a 95. 96 and up are OBDII, lots of extra sensors and other crap. If your pulling a computer from a junk yard I would check the option sticker in the trunk for the autobahn package. Not sure what the code is.

I'm not 100% sure about you needing an autobahn PCM. Maybe someone can chime in here, but I've heard some horror stories about people putting non-autobahn trannies in autobahn cars and having lots of trouble.

The other option might be to get a non-autobahm ECM and pull the PROM form your ECM and swap them. The prom programming would probably be the only thing different between the two type of cars.

The other thing to is that you may want to buy a NEW ECM. I think these thinks fail because the PCB boards start to crack and eventually you start having open circuits and what not. Maybe putting a used one in wouldn't be the best idea. The part number for my car (non-autobahn) is 88961146 and it goes for $140 on gmpartsdirect with a $70 core charge. I don't think this includes the PROM.

Heres the thing, maybe your prom is bad, or maybe your PCM is bad. I couldn't tell ya. I would put my money on the PCM, but it could be the PROM.

[senrab]

Well I replaced the ECU with one fromGMpartsdirect ... swapped the PROM and everything is good! I appreciate the help and just wanted to follow up with the conclusion.

Thanks

[ghutchin]

Sweet