JusticeTT Posted June 4 Share Posted June 4 (edited) 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 Edited June 4 by JusticeTT (see edit history) Quote Link to comment Share on other sites More sharing options...
JusticeTT Posted August 16 Author Share Posted August 16 (edited) 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! Edited August 16 by JusticeTT (see edit history) Quote Link to comment Share on other sites More sharing options...
JusticeTT Posted September 25 Author Share Posted September 25 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? Quote Link to comment Share on other sites More sharing options...
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