Transmission upshifting too soon
Thread Starter
Intermediate
Joined: Sep 2018
Posts: 277
Likes: 73
From: GA
Transmission upshifting too soon
I have had this problem practically for as long as I can remember with my 01 LS430, I bought it with 186k and now it has 223k miles.
Starting off from a complete stop is usually when I experience this problem. 1st, 2nd, and 3rd gear shifts seem normal but the 3rd to 4th gear shift happens too soon, bogs the engine down, then immediately jerks into a lower gear and accelerates normally.
I have drained and filled the transmission fluid 3 times with T-IV over the time I have owned the car now the fluid is bright red. When driving the car aggressively this problem never happens, only when casually driving and always when going up hill. No check engine light is on, but will it turn on for transmission problems? I just thought about it I've never tried to check transmission codes I'll do that tonight.
Starting off from a complete stop is usually when I experience this problem. 1st, 2nd, and 3rd gear shifts seem normal but the 3rd to 4th gear shift happens too soon, bogs the engine down, then immediately jerks into a lower gear and accelerates normally.
I have drained and filled the transmission fluid 3 times with T-IV over the time I have owned the car now the fluid is bright red. When driving the car aggressively this problem never happens, only when casually driving and always when going up hill. No check engine light is on, but will it turn on for transmission problems? I just thought about it I've never tried to check transmission codes I'll do that tonight.
Pole Position
Joined: Nov 2014
Posts: 3,254
Likes: 418
From: CALIFORNIA
I have had this problem practically for as long as I can remember with my 01 LS430, I bought it with 186k and now it has 223k miles.
Starting off from a complete stop is usually when I experience this problem. 1st, 2nd, and 3rd gear shifts seem normal but the 3rd to 4th gear shift happens too soon, bogs the engine down, then immediately jerks into a lower gear and accelerates normally.
I have drained and filled the transmission fluid 3 times with T-IV over the time I have owned the car now the fluid is bright red. When driving the car aggressively this problem never happens, only when casually driving and always when going up hill. No check engine light is on, but will it turn on for transmission problems? I just thought about it I've never tried to check transmission codes I'll do that tonight.
Starting off from a complete stop is usually when I experience this problem. 1st, 2nd, and 3rd gear shifts seem normal but the 3rd to 4th gear shift happens too soon, bogs the engine down, then immediately jerks into a lower gear and accelerates normally.
I have drained and filled the transmission fluid 3 times with T-IV over the time I have owned the car now the fluid is bright red. When driving the car aggressively this problem never happens, only when casually driving and always when going up hill. No check engine light is on, but will it turn on for transmission problems? I just thought about it I've never tried to check transmission codes I'll do that tonight.
The transmission follows engine and input from engine sensors via ECU.
What engine maintenance parts have been serviced?
Numerous engine sensors...
The A650-E transmission employs numerous fluid solenoid valves and fluid temperature sensor on wire harness inside transmission.....
Last edited by YODAONE; Sep 15, 2020 at 08:25 AM.
Thread Starter
Intermediate
Joined: Sep 2018
Posts: 277
Likes: 73
From: GA
Have you performed throttle body and air mix path cleaning?
The transmission follows engine and input from engine sensors via ECU.
What engine maintenance parts have been serviced?
Numerous engine sensors...
The A650-E transmission employs numerous fluid solenoid valves and fluid temperature sensor on wire harness inside transmission.....
The transmission follows engine and input from engine sensors via ECU.
What engine maintenance parts have been serviced?
Numerous engine sensors...
The A650-E transmission employs numerous fluid solenoid valves and fluid temperature sensor on wire harness inside transmission.....
I'm going to go out during lunch with my techstream and look for transmission codes.
No codes or anything out of the ordinary.
Last edited by jharris400; Sep 15, 2020 at 09:36 AM.
Lexus Champion
Joined: Oct 2019
Posts: 17,934
Likes: 1,702
From: Ohio
I had this exact issue on the 2-3 shift, I recently switched to a tuned ECU from All4swap and it completely corrected the issue as well as gave 5 more average mpg, 30hp at least and massively improved PWR mode throttle control and shifting sensitivity.
The stock computers simply get old after a while and have glitches. Let me clarify and mention I tried everything you did plus new VVT solenoids and new factory O2s and a bunch of other services and little things to try and get it to smooth out but it didn't help.
Mine is a 02 217k
The stock computers simply get old after a while and have glitches. Let me clarify and mention I tried everything you did plus new VVT solenoids and new factory O2s and a bunch of other services and little things to try and get it to smooth out but it didn't help.
Mine is a 02 217k
Last edited by Striker223; Sep 15, 2020 at 12:30 PM.
Thread Starter
Intermediate
Joined: Sep 2018
Posts: 277
Likes: 73
From: GA
I had this exact issue on the 2-3 shift, I recently switched to a tuned ECU from All4swap and it completely corrected the issue as well as gave 5 more average mpg, 30hp at least and massively improved PWR mode throttle control and shifting sensitivity.
The stock computers simply get old after a while and have glitches. Let me clarify and mention I tried everything you did plus new VVT solenoids and new factory O2s and a bunch of other services and little things to try and get it to smooth out but it didn't help.
Mine is a 02 217k
The stock computers simply get old after a while and have glitches. Let me clarify and mention I tried everything you did plus new VVT solenoids and new factory O2s and a bunch of other services and little things to try and get it to smooth out but it didn't help.
Mine is a 02 217k
I saw your ecu tune post in your thread, that's interesting what was the down time while you waited for the ECU?
Lexus Champion
Joined: Oct 2019
Posts: 17,934
Likes: 1,702
From: Ohio
Wow thank you for replying I figured I'd never find someone with similar problems. You may be right about it being the 2-3 shift, usually when it happens I'm not couting the shifts in my head so I guessed 3-4. I wonder if this could be a capacitor problem? I can easily replace the surface mount caps.
I saw your ecu tune post in your thread, that's interesting what was the down time while you waited for the ECU?
I saw your ecu tune post in your thread, that's interesting what was the down time while you waited for the ECU?
Pit Crew
Joined: Jul 2013
Posts: 136
Likes: 44
From: Ohio
Interesting thread, I have had the exact same issue since I bought my 03, it had 233K miles then and now has 247K. It has always been a little annoying, but for me it only happens under light throttle application, under moderate throttle application it will shift normally. Still haven't figured out the cause, but a malfunctioning ECU does make sense.
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Thread Starter
Intermediate
Joined: Sep 2018
Posts: 277
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From: GA
Interesting thread, I have had the exact same issue since I bought my 03, it had 233K miles then and now has 247K. It has always been a little annoying, but for me it only happens under light throttle application, under moderate throttle application it will shift normally. Still haven't figured out the cause, but a malfunctioning ECU does make sense.
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Thread Starter
Intermediate
Joined: Sep 2018
Posts: 277
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From: GA
I'm still experiencing this problem. I have tried another used ECU and had my original ECU tuned by all4swap. The ECT Power mode becomes almost unusable is normal traffic. When taking off from a start 1st gear is fine but once it shifts into 2nd gear it's like I pressed the gas pedal half way down even though I haven't touched it. I've been told that is a sign of a bad ecu but all4swap didn't give any indication on what was wrong or how to fix it. I have checked the capacitors with an ESR meter and even replaced some of them without any difference.
I think I will try another ECU just for the fun of it but instead of 89661-50550 I'll get the replacement 89661-50552.
I think I will try another ECU just for the fun of it but instead of 89661-50550 I'll get the replacement 89661-50552.
Thread Starter
Intermediate
Joined: Sep 2018
Posts: 277
Likes: 73
From: GA
Advanced
Joined: Dec 2017
Posts: 716
Likes: 168
From: FL
I'm still experiencing this problem. I have tried another used ECU and had my original ECU tuned by all4swap. The ECT Power mode becomes almost unusable is normal traffic. When taking off from a start 1st gear is fine but once it shifts into 2nd gear it's like I pressed the gas pedal half way down even though I haven't touched it. I've been told that is a sign of a bad ecu but all4swap didn't give any indication on what was wrong or how to fix it. I have checked the capacitors with an ESR meter and even replaced some of them without any difference.
I think I will try another ECU just for the fun of it but instead of 89661-50550 I'll get the replacement 89661-50552.
I think I will try another ECU just for the fun of it but instead of 89661-50550 I'll get the replacement 89661-50552.
Thread Starter
Intermediate
Joined: Sep 2018
Posts: 277
Likes: 73
From: GA
I didn't bother to look at the vehicle speed sensor I guess I incorrectly assumed that was only used for the speedometer. Thank you for the suggestions on the ecu not giving a code I wish I had removed the rear sensor now. If I get desperate enough I will replace the sensors.
As a note I replaced the throttle body TPS with an OEM one a few years back and the MAF with a denso unit bought from Rockauto. So far with the new ecu I haven't noticed the upshifting problem, but usually with the old ecu I didn't notice the problem until a week or so after removing power to do a reset.