Harsh downshift for 2006 gs300

30

Asked by Jan 29, 2017 at 05:30 PM about the 2006 Lexus GS 300 AWD

Question type: Maintenance & Repair

My 2006 gs300 and has a harsh down shift from
2nd to 1st gear when coming to a complete stop.
One transmission place said replace ECU, dealer
said new transmission. I replaced transmission and
still have same problem. Do I need to reset or
replace computer? Has any one had this problem

10 Answers

I am having this same problem with this right now, did u figure out what it was and get fixed properly?

50

I'm also having the same problem. Lexus dealership told me I needed a ECU update that costs 2k plus an additional 300 for install. I didn't have the money to fix it and now my car is having shifting problems. It got stuck in 3rd gear so I took it in and they said my tranny is starting to fail. Just yesterday my battery light lit up on my dash and today my car wouldn't start. So I jumped it and my power steering is not working at all plus my clock and my navigation/radio is not getting any power at all and all my warning lights on my dash are lit up. Does anyone know what the problem could be??

1 of 1 people found this helpful.
30

Yes, I got my ECU replaced and reprogrammed and now my car is running good as new. I don't know why there is not a recall on the ECU because plenty of people are having this problem and are getting misdiagnosed saying it's the transmission. The ECU controls the engine, transmission and anything electrical with these Lexus. I paid about $2,000 and I'm back on the road

3 of 3 people found this helpful.
30

Hello Everyone -- I'm currently in the same situation. I had a rebuilt transmission (brand new kit), new valve and learned the computer is not recognizing the new valve -- six solenoids. The new computer will cost me $1550 on top of the $2200 I had to pay for the transmission and labor. My mechanic will not charge me for the valve. I agree, their should be a recall notice and/or update on the NHTSA website. I've visited their site and have learned about several issues related to this make and model car transmission. How can we alert Lexus of this problem and shift the cost to them for their repairs?

1 of 1 people found this helpful.
Best Answer Mark helpful
30

I'm not sure how or where to start when it comes to getting Lexus to acknowledge this problem. I didn't purchase my car from the dealer but this is definitely an issue. As far as the actual maintenance once the transmission is change you need to have your computer program so it can learn the new transmission because it's probably still reading the old one.

50

Ok you guys. I have a solution. There is a place called LKQ that sells used CPU's for a couple hundred. I just purchased mine for $400 and am taking it to the dealership sometimes this week to get it flashed over to my VIN so it can be used with my car. The dealership said they would charge me 1 hour labor to flash and install it in my car, which is $160. My car is jolting when coming to a stop around 8mph. It does it every time and the reason why is because my CPU is bad. In order to order the part you will need to open your hood and ok the drive side, by the windshield there is a black box that contains your CPU. There are numbers on it and you will need to write down the Toyota number. On my 06 gs300 my number is 89666-30352. I called LKQ and they had one in stock. Here is the website https://www.lkqcorp.com/en-us/ The representative at LKQ that Helped me is Missy and this is her direct line 209-235-5142. Lexus also told me I needed a CPU update and a new or rebuilt transmission. My transmission is perfectly fine, I believe. I will give an update once I get my part installed. This is a photo of the CPU I purchased from LKQ

4 of 4 people found this helpful.

I INSTALLED THE ECU HAD THE FLASH ALL 02 SENSORS PLUGS BELT ND THE CAR DID NOT GO PAST 60MPH ABOUT 3MONTHS LATER VERY DISAPPOINTED WITH THIS 06 GS300 LOOKS GREAT BUT I FEEL LIKE MY 94 GS WAS STRONGER

THE ANSWER IS 89666-30354 ECM COMPUTER & REMAN TRANS NOT REBUILT ND TRANS HAS TO UPDATED TO CORRECT ORGINAL MANUFACTURERD DEFECT SO USED IS A WASTE OF MONEY LEXUS DID US 06 OWNERS WRONG THIS TIME

Wish I would have read Melissa's post first. Gonna cost me $2000 for same problem. Did get a coupon for 15% off. Make sure you are on Lexus mailing list.

I have a friend who has had the same problem with the 06 GS300. Both of us are in the electronics service business so we thought we would have a look at the ECU and see if we could determine the fault. The processor on the ECU was ruled out as the fault, as the unit still shifted, just harsh on the 2 to 1 downshift. We ordered some replacement Electrolytic capacitors and replaced them ( heat can effect these components ). This didn't fix the problem, so some more research and we found a similar problem reported with the Toyota RAV4. This turned our attention to the surface mount resistors on the ECU. After touching up all of the resistors with a soldering iron ( take ESD precautions ) the unit came good. It seems the surface mount resistors are prone to the heating and cooling cycles in the engine bay causing dry joins. If you are, or know someone who is handy with a soldering iron this would be worth a try ( you need to be able to identify surface mount resistors and be able to minimize electro-static discharge or risk doing more damage ). Search for RAV4 ECU repair to see what others have done. Attempt at your own risk and good luck.

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