1G Good TCU bought but does not shift still (shift kit works and shifts) what could be wrong

[FIBA M - EC17PSE]

I bought a tested working TCU as I found a nice one but cost a lot! Did it and installed it but its still stuck in limp mode (3rd)

How ever the shiftkit I installed to bypass this for now works and shifts every gear flawlessly! So I know its not the solenoids and I cannot get any codes pulled from the old TCU so where is my next step to problem solving this?

I would assume some wiring between trans and TCU but if that was the case the shift kit would not work either right? Since it relies on the same sensors and inputs in the trans to do the work?

Fuse is fine and wiring looks all good. I have the temp sensor disconnected as its mentioned to do this online so done that but either or does not difference.

Anything the TCU needs to see or read as to why its not shifting vs the shift kit let me know so I can dive into these specifics more?

Thanks all

 

[steve]

I assume it's a shift box like the Forced Four 150 you mean here because a shift kit is modifications to the valve body. Is that correct?

Are you able to read codes from the new TCU?

 

[FIBA M - EC17PSE]

I assume it's a shift box like the Forced Four 150 you mean here because a shift kit is modifications to the valve body. Is that correct?

Are you able to read codes from the new TCU?

I have a road surge V3. I found one so thats what im using as its simple install and i use the i use one on my 2G and love it.

As for your "because a shift kit is modifications to the valve body. Is that correct?" This im not sure i follow? I know it bypasses the tcu to control it manually but what the tcu sensors read or see i dont know. This is why im checking what the factory tcu requires to work and if somethings a miss i can chase that down bit by bit.

I had only just put it in and drown a few meters to see if it shifted. So i will need to drive around the block to give it a chance to try find a fault code to store. So will do that one another day. And hopefully by then i can check any other sensors suggested at the same time

The tcu it came with never spoke to me when i checked so if this one does not either i wonder if some wiring is an issue for this not telling me. Wiring is all unmodified (thankfully) so i would need to track down connections from start to finish to figure out if a break is in one or not.

 

[steve]

I have a road surge V3. I found one so thats what im using as its simple install and i use the i use one on my 2G and love it.

As for your "because a shift kit is modifications to the valve body. Is that correct?" This im not sure i follow? I know it bypasses the tcu to control it manually but what the tcu sensors read or see i dont know. This is why im checking what the factory tcu requires to work and if somethings a miss i can chase that down bit by bit.

You have a road surge V3 shift box. You might also have a shift kit installed but you didn't mention making modifications to the transmission valve body. I think I know what you are trying for figure out but you have to use the correct names or it just gets confusing.

I had only just put it in and drown a few meters to see if it shifted. So i will need to drive around the block to give it a chance to try find a fault code to store. So will do that one another day. And hopefully by then i can check any other sensors suggested at the same time

The tcu it came with never spoke to me when i checked so if this one does not either i wonder if some wiring is an issue for this not telling me. Wiring is all unmodified (thankfully) so i would need to track down connections from start to finish to figure out if a break is in one or not.

I can't find (remember where) my list of TCU codes ATM but if powered up and nothing is wrong it should spit out a heartbeat like the ECU does. That's a continuous on/off voltage on the diagnostic pin. If you get no voltage or a solid 12v then the TCU is either not powered or blown up. So at minimum you should be able to see if it's alive and if it sees a basic problem.

 

[steve]

Found them.. It's not clear about 1G TCU and heartbeat but I'd be surprised if they don't and it's just a documentation issue. It's called out in the 2G FSM.

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[FIBA M - EC17PSE]

Found them.. It's not clear about 1G TCU and heartbeat but I'd be surprised if they don't and it's just a documentation issue. It's called out in the 2G FSM.

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Yah I have this one saved from a while back and also printed thankfully. its very useful to have

 

[FIBA M - EC17PSE]

You have a road surge V3 shift box. You might also have a shift kit installed but you didn't mention making modifications to the transmission valve body. I think I know what you are trying for figure out but you have to use the correct names or it just gets confusing.



I can't find (remember where) my list of TCU codes ATM but if powered up and nothing is wrong it should spit out a heartbeat like the ECU does. That's a continuous on/off voltage on the diagnostic pin. If you get no voltage or a solid 12v then the TCU is either not powered or blown up. So at minimum you should be able to see if it's alive and if it sees a basic problem.

yeah I understand the names could be an issue so i have BOTH, short box and kit. I rebuild the VB as it was old and I wanted to inspect it and found some damage on the separator plate so replace that and now its all new and shift kit installed also at the same time for good measure as the balls are better etc etc as you know.

so both work now with the V3 RS shift box and buttons. but the stock TCU and this NEW tested one does not work so I will put the NEW one back in and go for a small drive to see what it figures out and then see what i get. i shall probe the main power wire to see if its even got any volts going to it as that would be a good first check. last time i believe I had nothing so no basic beat or noise from the buzzer setup so that makes me think of power and i did not know if it was TCU or going into the TCU as the issue. Now the new one wont work i need to check the power INTO the TCU and if nothing then i need to find that reason why then and start there

 

[steve]

but the stock TCU and this NEW tested one does not work so I will put the NEW one back in and go for a small drive to see what it figures out and then see what i get. i shall probe the main power wire to see if its even got any volts going to it as that would be a good first check. last time i believe I had nothing so no basic beat or noise from the buzzer setup so that makes me think of power and i did not know if it was TCU or going into the TCU as the issue. Now the new one wont work i need to check the power INTO the TCU and if nothing then i need to find that reason why then and start there

Yea, before you go for a ride do the quick test and see if you get a heartbeat from it. Make sure you're not otherwise pulling the diag mode pin (#10) to ground (like a datalogger will) because it will put all the control units into diag mode and then you have to talk to them to get anything back.

 

[FIBA M - EC17PSE]

Yea, before you go for a ride do the quick test and see if you get a heartbeat from it. Make sure you're not otherwise pulling the diag mode pin (#10) to ground (like a datalogger will) because it will put all the control units into diag mode and then you have to talk to them to get anything back.

Ok I can do that before the drive then. that's easy to do and I shall try do this next weekend and its a fairly quick process to swap out. its removed from the car currently so shall put it back in. I just don't get what else it could be as i really thought it was the actual TCU itself but maybe its not and mine is fine but something else is the issue. WHAT however is something I can google and search and not a lot comes up as a clear guide to figure out what or sensor etc etc. its likely to be something small and silly i overlooked no doubt

 

[steve]

I just don't get what else it could be as i really thought it was the actual TCU itself but maybe its not and mine is fine but something else is the issue. WHAT however is something I can google and search and not a lot comes up as a clear guide to figure out what or sensor etc etc. its likely to be something small and silly i overlooked no doubt

The goal is to get the TCU to tell us what it's problem with the transmission is. If it runs it should provide a clue as to why.

 

[FIBA M - EC17PSE]

The goal is to get the TCU to tell us what it's problem with the transmission is. If it runs it should provide a clue as to why.

Yeah that would be nice if it told me i can do something about that then but the oem one said get lost and im not waking up so left me wondering. New ones seems the same which bow has me wondering how both dont want to work/shift so might be sensor/wiring related. I will go back to the basics and start from scratch. Has to be as you say to see if its getting power and then go from there

 

[steve]

Maybe but it seems more like neither TCU were working, either cause they are dead, not getting power, or you have another logging cable like DSMLink plugged in. Since you can't easily reach pin 6 with that going on I mention it because you never know, people can be creative.

Power for the TCU uses both IG2 and unswitched backup power.

 

[FIBA M - EC17PSE]

Maybe but it seems more like neither TCU were working, either cause they are dead, not getting power, or you have another logging cable like DSMLink plugged in. Since you can't easily reach pin 6 with that going on I mention it because you never know, people can be creative.

Power for the TCU uses both IG2 and unswitched backup power.

this is a stock system for the most and non turbo so no dsmlink and not required. the new one was tested and working, i paid $500 for this one so also have a warranty to fall back on thankfully but o need to do the checks to see if its the tcu or chassis being the problem now