I believe my TCU (Transmission control unit) is playing up on my 94 NA AT, now I would like to know if the TCU's are interchangeable?, for e.g if I had a TT TCU would there be an issuing using it in my NA? Cheers
If it physically will plug in I think it will. But shift points will be to suit the TT. Is it JDM or ADM ?, I can give you part numbers to suit, and date range etc. There are several NA TCU's depending on date, the difference will be shift mapping in respect to the associated tune in the ECU. You could probably use any of them but if you want to retain the best drivability I think you would be best of using the right one. If it does end up being your TCU and you cant find the same one, you could change the ROM from yours to another good TCU which would retain shift mapping. Minimum charge at any good TV repair shop. I real good write up was done a while back on autos which included having the TCU tested and refurbished by a mob that specialises in auto control units. What makes you think its the TCU, whats happening ?
I have an 94 s2 ADM, transmission dash light has been flickering intermittently at startup, pulled a transmission signal error code on diagnostics a couple of times, also occasionally the box won't change gears out of 1/2nd just keeps revving past the shift points, it's intermittent at this stage but increasing in frequency, from what I can gather from searching online, could be a tps related issue, box issue, tcu issue, I have picked up a replacement tcu for testing purposes 31036-410P01 p/n is that from a TT or NA? Thanks for your help
ADM Control Unit-Shift (TCU) 03/92 - 01/94 31036-45P15 01/94 - onwards 31036-46P15 That part number has too many numbers, I will assume its 31036-40P01, which is a for a JDM TT 11/90-08/92.
The TPS sounds like a good place to start. ADM Z32 TPS part numbers 22620-12G11 10/92-01/94 $159 USD from CZP 22620-12G12 01/94 onward $74 USD from CZP Interestingly Z1Motorsports is saying ALL TPS's are the same. https://www.z1motorsports.com/throt...ssan/throttle-position-sensor-tps-p-1732.html This has been in question for some time and due to not having each unit side by side on a jig to compare sweep on an oscilloscope it has remained unanswered. Lot of respect for Z1 but will still keep an open mind on this, I would happily pay the extra $15 for the TT part number.
I would do a fluid and filter change on the auto first. I have the same problem with my z not shifting properly from 1st to 2nd gear. Revs out to like 5000 rpm then it jolts the car when shifting. Ive now done a double fluid change and the auto is shifting better. Its not perfect yet but considering i didnt touch my auto for 8 years my old atf was black and well past its due by date. I think the problem is the fluid pressure is low due to the badly thinned out atf fluid and causes the auto to not shift properly. I plan to do a quadtriple fluid change over the next few services until the next 40,000 km service to try and remove as much of the old atf fluid as i can and i hope that will fix my shifting problems.
Thanks for all your replies, the funny thing is, I never had an issue for 30,000ks since owning the car until I got the atf changed, threw a AT signal code almost immediately after that service and the issues have been popping up intermittently for the last 5,000ks, in going to try out this TT tcu, if that fails I'll send it in for an early service and have the tps checked and atf changed. I'll post my results.
Mines been throwing up a tps signal and speed sensor signal for ages, i replaced the tps but nothing changed. I read a thread on here stating the oem auto ecus go bad and need to be checked he sent it to injectronic through repco who reapldered the circuit board in the ecu to fix the error codes coming up.
That's good to know, I have a feeling it's the tcu, hopefully I'll have some results in a few weeks time after a reasonable number of Ks clocked on the replacement tcu
Its possible i want to get my refurbished at some point in time to make sure its 100% working. I borrowed a mates ecu a year ago to see if it fixed the problem but still had shifting problems. So far with my fluid changes ive gone from 5000+ rpm from 1st to 2nd gear down to 3500 rpm. The shifts are more consistant now since the second flush but i still get a jolt when shifting from 1st to 2nd gear. Keep us informed on your results.
Ok just an update for those who are interested, swapped in the replacement series 1 TT TCU into my series 2 NA, The S1 replacement was built by Hitachi and the original S2 in my car was built by Unisia Jecs Corporation, not sure if this is significant or not but could be useful. *AT check light did not flash on startup, it previously did almost everytime *up and downshifts aren't as noticeable *one thing I did notice that was if I left the OD off when traveling over 80km/h and booted it, it revved out to 5k and did not automatically shift up, the check AT light came on momentarily so I backed off the accel and the Check AT light went off, *OD works fine when depressed over 80, similarly if hovering just under and switch if off, it downshifts. Still to early to determine if the problem is solved, but so far i'm happy with how its heading. Will post more notes once I get more driving done with it.
Glad to hear you are happy with the way things are going. Not trying to start anything but do yourself a favour lose the "series" 1 and 2 thing, it doesn't mean anything, it can not be defined and it just confuses everything and leaves a poor legacy for the future users of the forum.
May I add... from experience, what you did might be a band aid. The Z autos are now getting on a fair bit and God only knows how much punishment they have coped all these years by previous owners. Treat it with respect and don't thrash it all the time if you want it to last a little longer. I rebuilt mine and it's so much better compared to an old 20+ yr old Auto in terms of holding power. If you fang it all the time, expect/factor in a rebuild, that's what I am trying to say. A rebuild is 2.5K approx. Peter
I appreciate your advice but your assumptions re my driving habits are off. I am the second owner, first being a retired accountant. Has not had a hard life by any stretch either by me nor the previous owner. Full dealership service history, Never missed a service by previous owner nor myself. Maybe my language threw you off, i needed to test the functionality of the replacement tcu by "booting it" as I knew the original TCU had shifted to 4th regardless of if the OD was depressed or not once it reached a certain rpm. Thanks for the advice.
