94LuminaZ34 Posted December 28, 2008 Report Share Posted December 28, 2008 Ok some of you have seen my recent post about my ongoing tcc problem well since I confirmed that the transmission was not at fault and that it was a communication problem between the PCM and Transmission but all wires, sensors and solenoids check out fine so I decided to just bypass the TCC which is easier said then done on the 94 3.4L because of the way the pcm is programed and the dtcs that it throws so after some thought I came up with a simple soultion of using a relay that will trick the computer into staying out of lockup I just test this today and it works great I have all four gears and no check engine light and I was also able to wire my TCC solenoid to a ground switch in the car so its there if I need it. Here is the wiring diagram for anyone that wants to do this. When you have wired in the relay just run the TCC solenoid wire into the car and hook it to a switch that is hooked to ground. You shouldnt have any problems leaving it this way other then gas milege just dont forget when you have it turned on or you could burn up the transmission.Oh and one last thing cruise control will be disabled if you do this. Quote Link to comment Share on other sites More sharing options...
Crazy K Posted December 28, 2008 Report Share Posted December 28, 2008 NO! absolutely NOT. you have complicated a simple problem. if you actually need to disable the tcc, you can disable it at the brake switch by snipping the CORRECT wire... and be done. running OBD1.5 on my cars, I have snipped the PWM selonoid wire with NO issues. but what is the issue with your car? Quote Link to comment Share on other sites More sharing options...
94LuminaZ34 Posted December 28, 2008 Author Report Share Posted December 28, 2008 The computer wont hold the TCC solenoid on for some reason it turns it on then back off. With it wired to the switch it works like it should. If you snip the wire from the brake switch to the pcm you have the possibility of getting a brake switch code P0703 that would disable fourth gear after the car has been driven over 35mph for 10 seconds and back to zero 5 times without seeing the brake switch applied and released. And it would also disable cruise control. Cutting the PWM wire has the possibility of getting a P1650 code it wont light the engine light but it will be stored because the PCM is not seeing the right voltage from the harness. Quote Link to comment Share on other sites More sharing options...
Crazy K Posted December 28, 2008 Report Share Posted December 28, 2008 snip the PWM wire. if that solves the issue... then you're done. ALSO I recommend adding a transmission cooler. all the 4t60e trannys seem to perform more consistently with one in place. Quote Link to comment Share on other sites More sharing options...
94LuminaZ34 Posted December 28, 2008 Author Report Share Posted December 28, 2008 Already tried that and it didnt work. For some reason the computer wont hold the solenoid on. I hooked up a mastertech scan tool and when I turned on all the solenoids one by one all would come on and stay on except the TCC it would come on and go off every four seconds, because of this it would set a P0740 and default me to third or second gear everytime I drove above 50 and the computer saw that the car was not in lockup for 10 seconds. Quote Link to comment Share on other sites More sharing options...
Crazy K Posted December 28, 2008 Report Share Posted December 28, 2008 could it be a bad PCM? Quote Link to comment Share on other sites More sharing options...
94LuminaZ34 Posted December 28, 2008 Author Report Share Posted December 28, 2008 I swapped PCMs and it did the same thing but I was using the same memcal so I'm going to try a different memcal. I have one I'm just waiting on a VATS Bypass so I can use it in my car I should get it next week. Quote Link to comment Share on other sites More sharing options...
ManicMechanic Posted December 28, 2008 Report Share Posted December 28, 2008 Lumina with VATS? Quote Link to comment Share on other sites More sharing options...
94LuminaZ34 Posted December 28, 2008 Author Report Share Posted December 28, 2008 I bought a used PCM but the memcal was programmed with VATS (PASSKEY)so I think it came from a different 94 or 95 3.4L maybe a Pontiac or Olds. It has the same part number as mine so it should work 16196401 . Quote Link to comment Share on other sites More sharing options...
Crazy K Posted December 28, 2008 Report Share Posted December 28, 2008 ?!?!?!?!?!?!?!? the 94 has no VATS. but if you were to put the memcal from a car that had vats... it shouldn't run..... so you need to try a memcal from another 94 3.4 lumina... so to be clear, the selonoid basically doesn't seem to be holding, and you can test it with a tech tool... if you disconnect the PWM selonoid wire... would the TCC selonoid still hold? wait.... does a 94 have a PWM selonoid? Quote Link to comment Share on other sites More sharing options...
94LuminaZ34 Posted December 28, 2008 Author Report Share Posted December 28, 2008 I know the lumina had no vats but the memcal from the other computer I bought has it so I have to bypas it in order to get it to work in my Z34. The solenoid will hold if I control it but if I let the computer do it something goes wrong and it turns off and throws me into default gear P0740. The 94 does have a PWM solenoid but I have tested it and all the other solenoids and all the wires for shorts and amp draw and everything is in perfect condition. If its not the memcal then it just might have to stay bypassed. Quote Link to comment Share on other sites More sharing options...
GP1138 Posted December 28, 2008 Report Share Posted December 28, 2008 it was a communication problem between the PCM and Transmission This seems to be your problem. Any PCM with VATS will not be appropriate for your car, being a '94 Lumina, it should still be Ol' Dirty Bastard I. Try replacing the PCM entirely with a '94-down 3.4L PCM. I would imagine that the OBD 1.5 PCM/Memcal would not function properly in your PCM. Quote Link to comment Share on other sites More sharing options...
94LuminaZ34 Posted December 28, 2008 Author Report Share Posted December 28, 2008 My PCM is already a 1.5 OBD. The memcal I have in it now is the stock one so I'm trying to change it with a different one but the only onther one I have has VATs programmed into it so once I bypass that the car should run just like the 3.4L that the computer and VATS memcal come out of. Quote Link to comment Share on other sites More sharing options...
GP1138 Posted December 28, 2008 Report Share Posted December 28, 2008 My PCM is already a 1.5 OBD. The memcal I have in it now is the stock one so I'm trying to change it with a different one but the only onther one I have has VATs programmed into it so once I bypass that the car should run just like the 3.4L that the computer and VATS memcal come out of. I was under the impression that the '94 down Luminas have OBD 1 still, rather than 1.5. This is interesting. Can you take a picture of your ALDL port, so we can see the pins? That would settle it. Quote Link to comment Share on other sites More sharing options...
oldscsc Posted December 28, 2008 Report Share Posted December 28, 2008 My PCM is already a 1.5 OBD. The memcal I have in it now is the stock one so I'm trying to change it with a different one but the only onther one I have has VATs programmed into it so once I bypass that the car should run just like the 3.4L that the computer and VATS memcal come out of. I was under the impression that the '94 down Luminas have OBD 1 still, rather than 1.5. This is interesting. Can you take a picture of your ALDL port, so we can see the pins? That would settle it. Any LQ1 car is OBD 1.5 IIRC. Quote Link to comment Share on other sites More sharing options...
94LuminaZ34 Posted December 28, 2008 Author Report Share Posted December 28, 2008 Heres the ALDL port A B M. Jumping the pins does not flash the check engine light and the PCM has OBD2 codes so that makes it a OBD 1.5 right? Quote Link to comment Share on other sites More sharing options...
Crazy K Posted December 28, 2008 Report Share Posted December 28, 2008 94 luminas are an odd bag, 3.4 cars are OBD 1.5 3.1 are obd 1. there is no VATS in the 94 lumina why not get a known good chip from a 94 lumina 3.4? DOHCv6 might have one. Quote Link to comment Share on other sites More sharing options...
94LuminaZ34 Posted December 28, 2008 Author Report Share Posted December 28, 2008 Once I get the part to bypass the VATS system on this other chip I will know if it is infact the computer or programming. Again I think the chip came out of a pontiac or olds but it was in a computer that is the same as mine part numbers match. It might have come out of a 95. Quote Link to comment Share on other sites More sharing options...
Crazy K Posted December 29, 2008 Report Share Posted December 29, 2008 i don't think it would be reasonably possible to bypass the vats. better to try a 94 lumina specific chip. I might even have one. can you get me the code off of yours??? Quote Link to comment Share on other sites More sharing options...
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