I have a 1uzfe from a 92 sc400 in my 4runner and my mechanic friend and I are trying to get it running with a a340f transmission. The 2 shift solenoids are connected correctly to the ecu but the truck never shifts out of 1st gear. If I remove the wiring harness I can manually shift to L, 2, or D and get 1st, 3rd, or O/D that way, so I know that the transmission is fine. We are using the lexus speed sensor in the tranny with the a340f sprocket so it should be getting the right speed. Are there any other things that we should check into or some diagnosis ideas? We're kind of stuck right now and any help would be greatly appreciated.
The 1UZFE EGR Delete Kit is available for sale here.
thats what i am thinking. i ordered capacitors to replace the existing ones in the ecu even though they look fine. i have read on more than one occasion that they can be bad with no visible signs of failure..
a good write up over at club lexus
http://www.clublexus.com/forums/ls4...exus-issues-solved-ecu-leaking-capacitor.html
ill post back after i get them in there
gloverman
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So you are running the SC400 ECU/ECT powertrain unit at the moment? Did your A340F come from a 22RE which is controled by the 22RE ECU/ECT powertrain unit or was it one which ran a separate ECT for the transmission? Does your A340F have the overdrive speed sensor? Does your A340F have 3 or 4 solenoids? Have you connected a scan tool to monitor what speed the ECU is seeing? And shifter position? Have you monitored if the ECU is driving the solenoids?
Thanks for your questions and suggestions. Yeah we're running the ECU/ECT from the SC400. The a340f is from a 98 t100, and it has 3 solenoids. Not sure if it has the overdrive speed sensor, I'll have to check that out. Does the SC400 brain need an O/D sensor for shifting?
I don't have a scan tool so I'm not sure how to check any of that stuff. I believe that we are getting an on signal for one of the solenoids because it stays in 1st gear when it's in drive, 2, or L. I think if both of the solenoids were off it would change gears like when the transmission harness is disconnected.
I don't have a scan tool so I'm not sure how to check any of that stuff. I believe that we are getting an on signal for one of the solenoids because it stays in 1st gear when it's in drive, 2, or L. I think if both of the solenoids were off it would change gears like when the transmission harness is disconnected.
krayn
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From memory their is different trigger wheels on the output shaft of the a34xx trans. It may be recieving only half the pulses, thus thinking your not going fast enough to shift.
gloverman
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Have you checked the solenoids themselves?
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Not sure about '92 SC400, but '92 LS400 runs 2 o/d sensors. 1st one (sp2+/sp2-) is reluctor type, 4 pulse per revolution. Second one is Hall effect sensor, 20 pulses per rev, it goes to cluster where frequency is lowered to 4 pulses per rev, and then the modified signal is fed into ECU.
Krayn is right that your transmission is very likely to have wrong o/d pulses per rev. More specifically, I believe it has more pulses per rev than ECU wants to see.
Krayn is right that your transmission is very likely to have wrong o/d pulses per rev. More specifically, I believe it has more pulses per rev than ECU wants to see.
BlackUZZ31
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check SP1 and SP2 at ecu, also check the gear position sensor is correctly reporting D 2 L to the ecu
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mer10z you need at least one sensor in the back of the transmission with the correct pulses per rev. (apart from the absolutely necessary sensor near the torque converter)
Also, in addition to what BlackUZZ31 said, check that when in D position, there's +12V at NSW pin, and when in P or N there's 0V.
Also, in addition to what BlackUZZ31 said, check that when in D position, there's +12V at NSW pin, and when in P or N there's 0V.
jmswltn
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i do not have 12 volts at this pin at this pin. there is .6 volts at all times key on
i am attempting to use the drive shaft flange bolt heads for a 4 tooth rotor.
i get an a/c voltage doing this so i believe it is working. i am not throwing codes but i have not had it on the road yet since just parked with no driveshafts.
but still no shift from first i reved to 4300 or so but nothing
i am attempting to use the drive shaft flange bolt heads for a 4 tooth rotor.
i get an a/c voltage doing this so i believe it is working. i am not throwing codes but i have not had it on the road yet since just parked with no driveshafts.
but still no shift from first i reved to 4300 or so but nothing
gloverman
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Have you checked if your gearbox has the Overdrive sensor - this is the one at the front of the gearbox.
I would also check for transmission codes. The SC400 ECT is designed to work with 4 solenoid (2 for shift , one Overdrive (#3) and line pressure). Sounds like you have a gearbox with only 3.
I always wire in a diagnostic plug and use the scan tool to monitor the little info that there is for the auto. Speed input is there and Neutral switch is there. Also TPS input is important for transmission shifting.
I would also check for transmission codes. The SC400 ECT is designed to work with 4 solenoid (2 for shift , one Overdrive (#3) and line pressure). Sounds like you have a gearbox with only 3.
I always wire in a diagnostic plug and use the scan tool to monitor the little info that there is for the auto. Speed input is there and Neutral switch is there. Also TPS input is important for transmission shifting.
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as long as there's 0v at NSW it won't shift out of 1st...check your park/neutral switch wiring
jmswltn
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ok so there wasn't 12v at nsw so i helped it to see 12v and no difference
in the diagram it shows nsw should only see 12v at cranking why should there be voltage during on/running state?
in the diagram it shows nsw should only see 12v at cranking why should there be voltage during on/running state?
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cause it has internal pull up resistor. so if there's nothing connected to the pin, it will read 12v
in fact, STA is there to see cranking, and NSW is to check for park/neutral. If you analyze starting sys. diagram you will find out that in P or N , NSW is effectively grounded via the small resistance of starter relay. It does see 12v when cranking however.
in fact, STA is there to see cranking, and NSW is to check for park/neutral. If you analyze starting sys. diagram you will find out that in P or N , NSW is effectively grounded via the small resistance of starter relay. It does see 12v when cranking however.
jmswltn
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ok i understand that now why is the ecu not pulling it up to 12 volts?
also o/d off light is on always except when checking codes than it blinks appropriately for said codes when i remove a component to cause one otherwise no codes
also o/d off light is on always except when checking codes than it blinks appropriately for said codes when i remove a component to cause one otherwise no codes
jmswltn
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before i swapped this in the trans shifted fine despite a no.1 speed sensor error.. now even having that fixed it refuses to shift. i am not seeing any power wires i have not hooked up were would it get the 12v from?
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ECU receives positive 12v at +B,+B1,BATT and IGSW (all must read high when ignition is on). Negative power terminals are E1,E01,E02 etc.. - be sure to check all of them
So, if there's nothing (double check) connected to NSW pin, ignition is on and still there's no 12v at NSW, the ECU is very likely to be stuffed
So, if there's nothing (double check) connected to NSW pin, ignition is on and still there's no 12v at NSW, the ECU is very likely to be stuffed
jmswltn
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thats what i am thinking. i ordered capacitors to replace the existing ones in the ecu even though they look fine. i have read on more than one occasion that they can be bad with no visible signs of failure..
a good write up over at club lexus
http://www.clublexus.com/forums/ls4...exus-issues-solved-ecu-leaking-capacitor.html
ill post back after i get them in there
Last edited:
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I doubt it's the caps. Aluminium caps never short when they fail, so they just can't lead to "no DC voltage" situation. Anyway you would better borrow another ecu then trying to fix your one having only slight assumptions. Maybe you made mistake locating NSW pin or something like that.
jmswltn
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i definitely have something going on. i found last night that i have no power to my hi beams after the swap.
just to be sure 12v to nsw is the same with vehicles running the a341e (now f)?
from what i read through that thread that all people experienced positive results for a variety of unexplained symptoms with most makes and models after replacing the caps. soldering is pretty easy for me so for 9$ in parts and shipping and an hour or so in time spent is well worth it if it makes it run even a little better. they should be delivered today..
just to be sure 12v to nsw is the same with vehicles running the a341e (now f)?
from what i read through that thread that all people experienced positive results for a variety of unexplained symptoms with most makes and models after replacing the caps. soldering is pretty easy for me so for 9$ in parts and shipping and an hour or so in time spent is well worth it if it makes it run even a little better. they should be delivered today..
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