RX300 not shifting into overdrive.
CL Community Team
Joined: Apr 2001
Posts: 16,583
Likes: 1,397
From: Austin, TX
Yes, we know what you desire, the problem is sensor outputs go the computer. The program then decides what to do to the fuel, air, spark timing and transmission. The program is part of the microcode.
As you know there are hacks to provide signals to the ECU and that procedure is considered tampering with emission control and is illegal.
Salim
As you know there are hacks to provide signals to the ECU and that procedure is considered tampering with emission control and is illegal.
Salim
Driver School Candidate
Joined: Dec 2018
Posts: 6
Likes: 0
From: AL
O.K. Thanks.
Is there a pin-out diagram available that shows all inputs to the ECU from all these sensors? I could then physically follow the circuit board tracks and see if I have a bad capacitor or diode, or something else. That would be great
Thanks Salim!
Is there a pin-out diagram available that shows all inputs to the ECU from all these sensors? I could then physically follow the circuit board tracks and see if I have a bad capacitor or diode, or something else. That would be great
Thanks Salim!
Last edited by marcov; Dec 3, 2018 at 05:19 AM. Reason: mistake
Driver School Candidate
Joined: Dec 2018
Posts: 6
Likes: 0
From: AL
I'm now trying to replace Knock sensor "Cable", however the wires on the vehicle (1999 RX300) are going from the knock sensors into a big bundle(>1 inch). The cable I received has three connectors, 2 for the sensors and 1 on the other end at about 16". Is there a hidden connector in the bundle???
Lexus Test Driver
Joined: Apr 2008
Posts: 1,058
Likes: 126
From: Illinois
I'm now trying to replace Knock sensor "Cable", however the wires on the vehicle (1999 RX300) are going from the knock sensors into a big bundle(>1 inch). The cable I received has three connectors, 2 for the sensors and 1 on the other end at about 16". Is there a hidden connector in the bundle???
The bigger connector on the harness connects to the main harness of the engine.
Make sure you feel/hear a click on the connectors as you install them.
Double/triple check it.
You dont want to take it apart again once everything is together if not installed correctly.
Since you have everything apart, check the WATER INLET HOUSING plate.
With high mileage vehicles, coolant leaks out in that area.
Driver School Candidate
Joined: Dec 2018
Posts: 6
Likes: 0
From: AL
I dont know if you've done the work already but thats all you need.
The bigger connector on the harness connects to the main harness of the engine.
Make sure you feel/hear a click on the connectors as you install them.
Double/triple check it.
You dont want to take it apart again once everything is together if not installed correctly.
Since you have everything apart, check the WATER INLET HOUSING plate.
With high mileage vehicles, coolant leaks out in that area.
The bigger connector on the harness connects to the main harness of the engine.
Make sure you feel/hear a click on the connectors as you install them.
Double/triple check it.
You dont want to take it apart again once everything is together if not installed correctly.
Since you have everything apart, check the WATER INLET HOUSING plate.
With high mileage vehicles, coolant leaks out in that area.
Now I just stop, turn off the engine and start it up again and can travel (with overdrive) until I come to a complete stop again. It's a pain in the *** but the vehicle runs fine.......
I think I may need to change the ECU.......
Thanks for your interest in my post.
CL Community Team
Joined: Apr 2001
Posts: 16,583
Likes: 1,397
From: Austin, TX
Did not replace the cable because Rock auto sent me a cable that had different connectors. looked at all their other Knock sensor cables and they all have the same (wrong) connectors.
Now I just stop, turn off the engine and start it up again and can travel (with overdrive) until I come to a complete stop again. It's a pain in the *** but the vehicle runs fine.......
I think I may need to change the ECU.......
Thanks for your interest in my post.
Now I just stop, turn off the engine and start it up again and can travel (with overdrive) until I come to a complete stop again. It's a pain in the *** but the vehicle runs fine.......
I think I may need to change the ECU.......
Thanks for your interest in my post.
Salim
3rd Gear
Joined: Jul 2022
Posts: 3
Likes: 0
From: Washington State
My Lexus is doing the same thing no 4th gear should I just get a brand new ecm and just program it cuz I changed all the solenoids filter knockcencors ,o2 ,sparkplugs I never cleaned that ground or whatever's by the back tire, I got a mini vci techstream when my subscription expires it was only 2 day 1 can I still use the ob2 on it or is that expt to Thanx I like the car but might have to get rid of it and get a pony or something
CL Community Team
Joined: Apr 2001
Posts: 16,583
Likes: 1,397
From: Austin, TX
My Lexus is doing the same thing no 4th gear should I just get a brand new ecm and just program it cuz I changed all the solenoids filter knockcencors ,o2 ,sparkplugs I never cleaned that ground or whatever's by the back tire, I got a mini vci techstream when my subscription expires it was only 2 day 1 can I still use the ob2 on it or is that expt to Thanx I like the car but might have to get rid of it and get a pony or something
Anything mechanical or biological can give you trouble.
Please make sure you have a fully charge battery and then connect OBDII reader and read off any ECU codes that are present. if there are more than 1, write them down and then clear codes and re-read on the onset of CEL. Then diagnose based on the code.
Salim
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Lexus Champion
Joined: Apr 2019
Posts: 11,305
Likes: 1,616
From: FL
Welcome to ClubLexus.
Anything mechanical or biological can give you trouble.
Please make sure you have a fully charge battery and then connect OBDII reader and read off any ECU codes that are present. if there are more than 1, write them down and then clear codes and re-read on the onset of CEL. Then diagnose based on the code.
Salim
Anything mechanical or biological can give you trouble.
Please make sure you have a fully charge battery and then connect OBDII reader and read off any ECU codes that are present. if there are more than 1, write them down and then clear codes and re-read on the onset of CEL. Then diagnose based on the code.
Salim
Does the engine run well?
3rd Gear
Joined: Jul 2022
Posts: 3
Likes: 0
From: Washington State
What about resetting the ecm with the plug u plug your obd2 in .its number 13 and 4 I believe put a wire in there for 30 mins does that work or what it's supposed to clear the computer or reset it I don't want to short nothing out
CL Community Team
Joined: Apr 2001
Posts: 16,583
Likes: 1,397
From: Austin, TX
Keep in mind the ECM will have to be programmed to your key(s).
Have not heard about the error codes. Don't be tempted to clear the codes. Read them and note them and then clear. Disconnecting the battery for about 20 mins will clear the codes too.
Salim
Have not heard about the error codes. Don't be tempted to clear the codes. Read them and note them and then clear. Disconnecting the battery for about 20 mins will clear the codes too.
Salim
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