04 LS430 Sports shift mode 'engine braking' issue?
#17
Lexus Fanatic
iTrader: (1)
Interesting. My car will automatically downshift going down a hill but not until I tap the brakes. If I coast it will not downshift. It's never major engine braking. Just from 5th or 6th gear to 4th or 3rd.. I wonder what sensor is used to determine the angle of the vehicle. Sometimes the uphill not wanting to upshift is a lttle annoying. It will hold the lower gear a little too long.
Last edited by Lavrishevo; 12-12-14 at 07:02 PM.
#18
Intermediate
Thread Starter
Yeah I wondered it is was a faulty yaw sensor or something similar that determines the cars angle. I filmed the issue on my phone so I am hoping to post it up soon.
#19
Lexus Champion
The shop manual points to the ECM if you have "No engine braking".
Perhaps you can borrow a known-working ECM from a friend (or the dealer), and try it out on your car to see if you can eliminate the problem. Here's where you will find your ECM.
Perhaps you can borrow a known-working ECM from a friend (or the dealer), and try it out on your car to see if you can eliminate the problem. Here's where you will find your ECM.
#20
Lexus Fanatic
iTrader: (1)
Check this out. Look at the last post. One of those sensors may have failed. Where are they and can they be tested is the question.
https://www.clublexus.com/forums/ls4...vsc-off-7.html
Zero Point Calibration of Yaw Rate and Deceleration Sensors Using SST 09843–18040.
When having replaced the yaw rate sensor, deceleration sensor or the ECU, perform the process for zero point of yaw rate and deceleration sensors as shown below.....
When having replaced the yaw rate sensor, deceleration sensor or the ECU, perform the process for zero point of yaw rate and deceleration sensors as shown below.....
https://www.clublexus.com/forums/ls4...vsc-off-7.html
Last edited by Lavrishevo; 12-12-14 at 07:20 PM.
#21
Lexus Champion
More information on DLC3 terminal locations and SST 09843-18040 (which is essentially 2 short jumpers joined together to allow jumpering up to 3 terminals together). In this case, a paper clip or a short piece of wire will do the trick.
#22
Intermediate
Thread Starter
Lavrishevo, and rkw77080 you guys are the best! Thank-you so much! Just the info that you guys have found so far is more info than the Lexus dealer has been able to suggest or find in years!
Last edited by LEX ES300; 10-06-23 at 10:21 PM.
#23
Lexus Champion
This forum is filled with very informative and helpful folks - if you need reference material from Lexus shop manual, just simply ask! Please keep in touch and good luck...
#25
Lexus Champion
LEX ES300, Assuming that you've manually enabled the "engine brake" by moving the shifting lever from "D" to "S" while going down hill and did not feel any "braking", you may be having CAN (Controller Area Network) communication problem with the ECM. However, just to be sure, please take a second look at the instructions on the Owner's Manual...
If you have followed the instructions and your engine does not rev up when it down-shift, then here are a couple of "Inspection Procedures" for you to consider before you take the plunge for a replacement ECM.
If you have followed the instructions and your engine does not rev up when it down-shift, then here are a couple of "Inspection Procedures" for you to consider before you take the plunge for a replacement ECM.
Last edited by rkw77080; 12-15-14 at 11:12 AM.
#26
I've read thru most of these posts and have a question for you. Are you flipping the switch on the dash to active engine braking or are you actually using the console-mounted shift lever to cycle the the gears?
On a related note, I've noticed on many occasions that if I am driving on a slight downhill grade at 25-40MPH and tap the brake pedal, the car will retard the acceleration, all while in Drive. If I hit the gas, it resumes normally. I guess I am too lazy to read the manual to figure this feature out.
On a related note, I've noticed on many occasions that if I am driving on a slight downhill grade at 25-40MPH and tap the brake pedal, the car will retard the acceleration, all while in Drive. If I hit the gas, it resumes normally. I guess I am too lazy to read the manual to figure this feature out.
#28
Intermediate
Thread Starter
I've read thru most of these posts and have a question for you. Are you flipping the switch on the dash to active engine braking or are you actually using the console-mounted shift lever to cycle the the gears?
On a related note, I've noticed on many occasions that if I am driving on a slight downhill grade at 25-40MPH and tap the brake pedal, the car will retard the acceleration, all while in Drive. If I hit the gas, it resumes normally. I guess I am too lazy to read the manual to figure this feature out.
On a related note, I've noticed on many occasions that if I am driving on a slight downhill grade at 25-40MPH and tap the brake pedal, the car will retard the acceleration, all while in Drive. If I hit the gas, it resumes normally. I guess I am too lazy to read the manual to figure this feature out.
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01-28-11 09:14 AM