JusticeTT

Thank you kind sir, that is very helpful

Have obtained both an engine and a TRAC ecu. Should anyone take a moment to see prior post about concerns with immobilizer (and of note, aftermarket alarm) that would be helpful Additionally from a physical point of view - I see some screws are in awkward spots - Is the connector plug hard to remove - Wiring delicate? Any tips or tricks around removing the ECU unit(S)and replacing in relation to the above?

I might have found a source for both a main engine ECU and a throttle body ECU Based off what I can gather, the majority of times there's a type of symptom(S) as I've listed above here, that's often going to be more on the Engine ECU side than throttle body If I had to choose between the two, which to start with in particular to address ECU code 64 - Defective lock up solenoid or short circuit-severed wire harness or short circuit Another thing I am concerned about is the vehicle has an immobilizer. Some persons say you can simply plug and play the ECUs (parts matching) and you won't have to do anything with the immobilizer Others say you require a master key or be prepared to have to reprogram it My fear beyond the hassle of reprogramming is that it triggers the alarm or something and I can't shut the thing off!

Hello all, At kind suggestion I have started this up rather than continue it on in my 'hello' thread (Which you may find a good hearty read, and also gives some background) I appreciate the main issue I describe there relating to the transmission and the potential electrical symptoms have been covered quite extensively however I noticed that a lot of the historical examples point at or involve other error codes than the one I am tracking - such as 21, 42, And unfortunately the given (or assumed ) solutions are often to replace the ECU when that might not have been the real solution, it was what was last suggested before the persons stopped updating their ticket... While I am on the hunt to hopefully obtain one whether as a test unit or a replacement, I appreciate that's a challenge these days and it may not be the solution either What the symptoms are ECU code 64 - Defective lock up solenoid or short circuit-severed wire harness or short circuit For a time it was also giving code 89 - Open or short circuit in communication circuit between TRAC ECU and ECM ECU // or TRAC ECU malfunction though that has since ceased[unknown resolution] The vehicle does not downshift into Low from 2nd While in Low, it behaves effectively as that it's in 2nd while the gear level is in Low position and physically shows on the dashboard as well There are rare some occasions where should I leave it in L and start going along while it acts and behaves as 2nd, then it can down shift - seemingly random( catches you off guard when going ~ 20mph ) Overdrive sometimes does not engage consistently This can occur on up shifting or while it's already in Overdrive; meaning while in drive the Overdrive button is engaged yet it does not up shift <> conversely it can be in Overdrive, going along and it shifts down on it's own despite no change in throttle (or no noticeable change in throttle input) Manu mode and slip control blink on dashboard The frequency of this is not excessive It can happen as soon as the vehicle starts, or sometimes later during a drive with no specific pattern of time for it to begin (or time elapsed) On occasion the lights do not blink at all, and everything 'looks' as expected yet the 'physical' aforementioned issues persist, i.e. it can be showing as in Manu mode yet Low does not operate Under what conditions they occur Virtually any, however I have witnessed that the visual (the dash, lights etc) seem to be more prone to occurring when the temperature is on cooler side, say sub 20 celcius When it happens The physical element concerning Low and Overdrive is as soon as ignition and persists as a symptom until the car is turned off The visual /blinking lights can happen as soon as the vehicle starts, or sometimes later during a drive with no specific pattern of time for it to begin (or time elapsed) On occasion the lights do not blink at all, and everything 'looks' as expected yet the 'physical' aforementioned issues persist, i.e. it can be showing as in Manu mode yet Low does not operate When it started to misbehave About two years ago I had it in a garage covered and had been sitting for a period of three months, with weekly or two times a month start up and idles to operating temperature as well as a slight reverse or drive movement a few feet to mitigate some tire flat spotting I noticed the MANU button blink which caught my eye while sitting in the car while it idled one afternoon. When I pressed the button it hesitated to respond, seemingly. I left it and returned later in the year around February where I drove the vehicle and found no issue with the dash lights or the car itself I had it out a handful of times that year, no issues Come the next winter season(2023) I repeated the above and after a few engine turn overs during course of the months, I observed the blinking lights and hesitant manu mode button response Eventually March rolled around and when I took it out to drive, the lights were still acting up but...no physical issues I took out again not long after and then noticed the physical/drive issues began occurring What you've tried to do to fix it Research! I have lots of wiring diagrams, fault code charts, saved bookmarks and pinned tabs. I even was trying to use the Wayback machine to be able to see posts on the Australian Supra forums which are no longer visible though appear in search results Spoken to Chris Wilson about possible causes Tried searching for reputable mechanic, specialist or electrical engineer that can look at the ECU in event Chris is not able to solve Not yet located Fluid checks of many types I read somewhere that low coolant or coolant issues interpreted by the ECU might cause it to avoid lowest and highest gears as a somewhat safe measure Transmission was the main one was aiming for, looks red to me Alternator, waterpump and cam/timing belt replaced Had the passenger side well carpet up and checked the outside of the ECUs engine and trac, to ensure nothing clearly obvious with the connections or wiring Sourced ECU/trac code charts and run a code check Checked fuses in the engine bay/compartment for any breaks Reset ECU by removing EFI fuses Look for another ECU to swap/test with Not yet located What effect those fixing attempts had Currently no changes as a result Has led me to better understand how the vehicle operates and potential causes - new avenues to explorer Further notes, comments The vehicle was adjusted to have a mph conversion, many years ago. I found what seems to be the wire for that coming out of an ECU and the connection looks OK (see attached) What am I hoping to gain from this post Other than the obvious - a solution, also about confidence in which avenue and path I am pursuing as I appreciate these types of issues may be a long journey this could also be via ruling out any of the following Dry solder on any part of the run from bell housing back up to the odometer connections behind dash Transmission shifter wiring Odometer Delimiter/speed defender connection Speed Sensor Safety Neutral switch // "mlp sensor" Bad transmission Solenoid 1 and/or 2 Meet/be introduced to some great persons along the way

Still on the hunt for a spare working ECU to test with ; in meantime small followup in among my transmission issues I've done another code test recently and found it's no longer reporting 89 which was However the code 64 is still present Both the above chart and the below chart indicate it's a type of short circuit or issue with a solenoid valve 3 I am trying to find some diagrams/imagery on it A thing of note is the above states "Malfunction with code No. 64 is not indicated to the driver. But the code is stored in the memory" I am not certain how to interpret that. Does it mean by "indicate" that the code will not appear when doing a code diagnostic and watching the blinks, if that's the case then what is the six + four blinks I am observing related to then? Or does it mean that unlike other codes which give a warning light - hazard, abs, oil, engine etc, this one will not have it's own designated symbol? Provided the latter was true, then would that not apply to error 63 and 62 for the other solenoid valves?

Hi Benjy, did you still have a stock ECU after the turbo change? Do you recall adjusting anything on the loom or behind the dash? How about the transmission

While I am waiting on this to be hopefully approved by moderator.. I meant to include the following in my plans for next year, which is to do a belt and pulley system check/replacement Also..part codes I listed on the ECUs... ignore that with prejudice! Not sure why I listed those Image attached is from my boxes and they seem to line up with what's been posted prior What I find curious is A) 89661-14491 and 89661 -14490 Are listed as the Engine ECU according to the Supra forums via Ian and some others I presumed '90' as pre facelift and '91' was post facelift? Though while mine is definitely a prefacelift vehicle, yet my part ends in 91... B) For the throttle ECU, they have also listed a code in some part catalogues of 89670-14050 meanwhile mine is 89671-14010 I mention this as wondering whether that one can also work, possibly an alternative model units in event I cannot find exact replacement C) See that tape job on the Engine ECU. It's a soldered of a red wire that runs around back and into the console area and a peach/pink wire. I believe this might have something to do with the speed conversion to MPH? In one of the images right at carpet's edge you can see a pink piece of wire, looks like left over when whomever did the work I took the tape off gently and found it's soldered - can't tell the quality though it's together for sure. I've issued new tape and closed it all up 04/05 Update on the car's electrical behavior Wweather warmer today for certain. Started the car, no flashing lights. Manu mode responds instantly when pressing it. Out for a drive, results are : - Low is not respected, car's lowest gear is still 2nd - Manu seems to be respected otherwise. Example : while it's in 2nd won't shift up and similarly, drive won't go to Overdrive - Overdrive seems to be working more consistently (would need more testing time). Pressing the button on off get's near instant response from the transmission I really am thinking there's a temperature element to all this, given my previous experience about the storage period where this only seem to began after cold months storage and then symptoms start to cease with warmer climate

Hello good day I am a proud owner of a 94 JDM Supra, Automatic Twin Turbo in Toyota's lovely 199 Alpine Silver (OK I appreciate it's a common base coat though it's still nice!) She has been in my possession since around 2010 and is below 60,000 miles From what I can tell it's stock except for Work Equip alloys Auto watch alarm HKS dragger exhaust Good things about it It is a MKIV Supra ... Interior is superb, still has it's factory smell Clear coat is impressive, where there's no stone chips (collective sigh here everyone..I know, but something about a respray makes me feel like I am covering over the original..) Electronics have always been good(though see my recently developed issue below) Engine has been seemingly strong for it's age 18/20 MOTs pass record(one had exhaust leak on factory exhaust and other was thinning tire tread) As an American living here in England, my choices on what vehicle to have as a hobby was different than back home of course. And the concept of drag racing takes on a different meaning when you're on B-roads with aggressive crowning and massive dips and potholes from semi trucks warping the roads over the years So the idea of grabbing a powerful street car with Automatic transmission and not having any wide flat place to rip it, wasn't as appealing as it could have been That said I had always been a fan of Toyota engineering and pursued a Supra for some years before purchasing When this one came up I felt it was a good base platform whether to keep stock as is, and enjoy it in the purest form, or to modify later on The car does have it's own share of issues As mentioned before, I don't love parts of the paint due to the chips, though only I seem to notice them..somehow The underside has typical surface rust, such as on control arms, suspension, diff etcetc. - this does not extend to the body The ECU might be damaged? This past year or two I started getting error 89 and 63 TRAC each time I take it out of cold weather storage[garaged]. I get the dread blinking TRAC, MANU, OverDrive lights and the transmission doesn't always go into Overdrive, nor does it respect L drive I've now had the vehicle for half the time I have been in the country and decided it's time to take it's ownership a little more seriously And..gentlemen I am now passed the blood brainer barrier age of 40, which totally influences my decision making differently Plans for this year Have the rust removal/prevention work done( I am speaking to a professional team who do clean and spray and seal services) Try to solve the electronic error codes (not to name drop though Chris Wilson has kindly been giving me some wisdoms and anecdotes. He's willing to look over it and check solenoids and etc) Plans for next year Continuation of above as needed Full fluid change(sans the transmission, if it's clean from sample testing, I really don't to flush it unnecessarily) Possibly be convinced to get some of it resprayed? Unless someone can show me it's better to get the chips restored section by section That's it from me. When I am eligible to post on the sale/buy forum section, I'll be asking whether anyone has an interest in selling either the stock auto ECU main or ECU TRAC (or maybe have a spare I can put a down payment/collateral on and borrow to test) I believe the codes are 89541-14050 89631-14010 And if anyone can recommend some kind, passionate and knowledgable automotive mechanics, electricians or repair in the East Anglia area, please do Also happy to move my electronics issue to fault finding thread though I appreciate the subject matter has been done to death Though if it is ECU, my query then would be less about the fault finding itself and more how is the best way to proceed - Buy as many used ECUs you can find, fit them and hope it works? - Buy an after market (though I am told there never was any good aftermarket ECUs for the Auto TT - something else?