Official ECU thread
Thread Starter
Pole Position
Joined: Jun 2009
Posts: 269
Likes: 0
From: Hawaii
Official ECU thread
Okay so I'm thinking about replacing my ecu on my 93 sc400. My part number is 89661 24230. Is this the only ecu part number that is compatible with the 93 sc400? or is there other part numbers/ecu that are compatible??
My problems/symptoms-
1. On cold start ups, rpm bounces between 1000-2000 or idles high. sometimes the idle drops as the car warms up sometimes it doesn't. When the idle does drop, it drops slowly to zero and then stalls(happened a lot to me).
2. Very strong fuel smell on start ups and when car is running
3. car stalls, only starts up if I keep my foot on the pedal, once released it stalls every time.
4. check engine light stays on when the car is running, and when I try to pull the codes, nothing shows.
5. when driving 40mph+, car jerks when I let off the gas pedal.
6. when coming to a stop car jerks
I replaced my spark plugs, spark plug wire, maf sensor, idle air control valve, and cleaned the throttle body but still didn't fix my problem.
So can anyone help me out?? anyone experience the same symptoms or replace their ecu before??
Good Info from TheMole below:
My problems/symptoms-
1. On cold start ups, rpm bounces between 1000-2000 or idles high. sometimes the idle drops as the car warms up sometimes it doesn't. When the idle does drop, it drops slowly to zero and then stalls(happened a lot to me).
2. Very strong fuel smell on start ups and when car is running
3. car stalls, only starts up if I keep my foot on the pedal, once released it stalls every time.
4. check engine light stays on when the car is running, and when I try to pull the codes, nothing shows.
5. when driving 40mph+, car jerks when I let off the gas pedal.
6. when coming to a stop car jerks
I replaced my spark plugs, spark plug wire, maf sensor, idle air control valve, and cleaned the throttle body but still didn't fix my problem.
So can anyone help me out?? anyone experience the same symptoms or replace their ecu before??
Good Info from TheMole below:
No experience with these guys, but you can find ECU part numbers at the following link. They also sell remanufactured/refurbished ECUs:
http://www.siaelec.com/index.asp?Pag...S&Category=380
There are also a few companies on ebay that fix ECUs and offer a lifetime warranty on their work.
http://www.siaelec.com/index.asp?Pag...S&Category=380
There are also a few companies on ebay that fix ECUs and offer a lifetime warranty on their work.
Last edited by grindin8o8; May 14, 2010 at 12:25 AM.
ECUs are easy to replace and not that expensive- plus it's a very common thing to go out on SC 4s. The problems you're describing could definitely be an ECU issue from a lot of the threads I've read on the subject. I have a starting problem that I thought could have been my ECU so I replaced it with an ECU from a running SC and had no luck. But our symptoms were different.
I actually still have the spare ECU from the running car if you want it, let me know. The car it was in had 70k and he pulled it to install an AEM.
I actually still have the spare ECU from the running car if you want it, let me know. The car it was in had 70k and he pulled it to install an AEM.
IF this is an ECU thread I have a question.
The toyota crown majaesta was only availible in Japan. That car came with a 1uz-fe but the biggest difference is its ecu had no transmission control that was left completely up to the control of a completely seperate transmission ecu.
My question is could that ecu be used on a manual swapped V8 in the US but still be scanned by an ODB2 scanner if it was a 97+ ecu?
The toyota crown majaesta was only availible in Japan. That car came with a 1uz-fe but the biggest difference is its ecu had no transmission control that was left completely up to the control of a completely seperate transmission ecu.
My question is could that ecu be used on a manual swapped V8 in the US but still be scanned by an ODB2 scanner if it was a 97+ ecu?
Pole Position
Joined: Feb 2008
Posts: 389
Likes: 0
From: Fl
Okay so I'm thinking about replacing my ecu on my 93 sc400. My part number is 89661 24230. Is this the only ecu part number that is compatible with the 93 sc400? or is there other part numbers/ecu that are compatible??
My problems/symptoms-
1. On cold start ups, rpm bounces between 1000-2000 or idles high. sometimes the idle drops as the car warms up sometimes it doesn't. When the idle does drop, it drops slowly to zero and then stalls(happened a lot to me).
2. Very strong fuel smell on start ups and when car is running
3. car stalls, only starts up if I keep my foot on the pedal, once released it stalls every time.
4. check engine light stays on when the car is running, and when I try to pull the codes, nothing shows.
5. when driving 40mph+, car jerks when I let off the gas pedal.
6. when coming to a stop car jerks
I replaced my spark plugs, spark plug wire, maf sensor, idle air control valve, and cleaned the throttle body but still didn't fix my problem.
So can anyone help me out?? anyone experience the same symptoms or replace their ecu before??
My problems/symptoms-
1. On cold start ups, rpm bounces between 1000-2000 or idles high. sometimes the idle drops as the car warms up sometimes it doesn't. When the idle does drop, it drops slowly to zero and then stalls(happened a lot to me).
2. Very strong fuel smell on start ups and when car is running
3. car stalls, only starts up if I keep my foot on the pedal, once released it stalls every time.
4. check engine light stays on when the car is running, and when I try to pull the codes, nothing shows.
5. when driving 40mph+, car jerks when I let off the gas pedal.
6. when coming to a stop car jerks
I replaced my spark plugs, spark plug wire, maf sensor, idle air control valve, and cleaned the throttle body but still didn't fix my problem.
So can anyone help me out?? anyone experience the same symptoms or replace their ecu before??
grindin8o8,
Where are you in Hawaii?> My eldest is stationed on Oahu. Oh, I wish I was there right now ...
As for your issues ... you probably are having ECU issues. I went rhough similar issues with my 93 SC4.
I am at work right now but can provide the info you need to diagnose and correct this evening. Hit me up and I'll explain it all later ...
Pole Position
Joined: Feb 2008
Posts: 389
Likes: 0
From: Fl
Okay so I'm thinking about replacing my ecu on my 93 sc400. My part number is 89661 24230. Is this the only ecu part number that is compatible with the 93 sc400? or is there other part numbers/ecu that are compatible??
My problems/symptoms-
1. On cold start ups, rpm bounces between 1000-2000 or idles high. sometimes the idle drops as the car warms up sometimes it doesn't. When the idle does drop, it drops slowly to zero and then stalls(happened a lot to me).
2. Very strong fuel smell on start ups and when car is running
3. car stalls, only starts up if I keep my foot on the pedal, once released it stalls every time.
4. check engine light stays on when the car is running, and when I try to pull the codes, nothing shows.
5. when driving 40mph+, car jerks when I let off the gas pedal.
6. when coming to a stop car jerks
I replaced my spark plugs, spark plug wire, maf sensor, idle air control valve, and cleaned the throttle body but still didn't fix my problem.
So can anyone help me out?? anyone experience the same symptoms or replace their ecu before??
My problems/symptoms-
1. On cold start ups, rpm bounces between 1000-2000 or idles high. sometimes the idle drops as the car warms up sometimes it doesn't. When the idle does drop, it drops slowly to zero and then stalls(happened a lot to me).
2. Very strong fuel smell on start ups and when car is running
3. car stalls, only starts up if I keep my foot on the pedal, once released it stalls every time.
4. check engine light stays on when the car is running, and when I try to pull the codes, nothing shows.
5. when driving 40mph+, car jerks when I let off the gas pedal.
6. when coming to a stop car jerks
I replaced my spark plugs, spark plug wire, maf sensor, idle air control valve, and cleaned the throttle body but still didn't fix my problem.
So can anyone help me out?? anyone experience the same symptoms or replace their ecu before??
OP,
Try the following and report back:
Remove your IACV. Note the position of the plunger (is it all the way out?). Take IACV apart and note condition of bearings. Clean IACV with carb/choke cleaner, reassemble (with plunger all the way in) and re-install onto engine. Start car. Does the car run with foot off the gas? If yes then try next step below.
Let engine warm for 30 seconds. Turn engine off. Wait 30 seconds. Try starting engine again. Does car run well or sluggishly? Turn off engine again. Wait 30 seconds. Start engine a third time. Does engine run at all?
The IACV is a 100+ position stepper motor air valve whose position is set by the ECU. My ECU was bad so the IACV would stay closed (when it should have been open). When I was having problems with my car I would take my IACV off and reset it (plunger in), reinstall and the car would run fine. After a few minutes the engine would set it closed, stalling the engine. If I turned it off the ECU would automatically (incorrectly) close the IACV, causing it to cough and then ultimately stall.
Also, because the ECU was bad ... it would never throw an error code.
Let me know how it goes ...
Trending Topics
Thread Starter
Pole Position
Joined: Jun 2009
Posts: 269
Likes: 0
From: Hawaii
OP,
Try the following and report back:
Remove your IACV. Note the position of the plunger (is it all the way out?). Take IACV apart and note condition of bearings. Clean IACV with carb/choke cleaner, reassemble (with plunger all the way in) and re-install onto engine. Start car. Does the car run with foot off the gas? If yes then try next step below.
Let engine warm for 30 seconds. Turn engine off. Wait 30 seconds. Try starting engine again. Does car run well or sluggishly? Turn off engine again. Wait 30 seconds. Start engine a third time. Does engine run at all?
The IACV is a 100+ position stepper motor air valve whose position is set by the ECU. My ECU was bad so the IACV would stay closed (when it should have been open). When I was having problems with my car I would take my IACV off and reset it (plunger in), reinstall and the car would run fine. After a few minutes the engine would set it closed, stalling the engine. If I turned it off the ECU would automatically (incorrectly) close the IACV, causing it to cough and then ultimately stall.
Also, because the ECU was bad ... it would never throw an error code.
Let me know how it goes ...
Try the following and report back:
Remove your IACV. Note the position of the plunger (is it all the way out?). Take IACV apart and note condition of bearings. Clean IACV with carb/choke cleaner, reassemble (with plunger all the way in) and re-install onto engine. Start car. Does the car run with foot off the gas? If yes then try next step below.
Let engine warm for 30 seconds. Turn engine off. Wait 30 seconds. Try starting engine again. Does car run well or sluggishly? Turn off engine again. Wait 30 seconds. Start engine a third time. Does engine run at all?
The IACV is a 100+ position stepper motor air valve whose position is set by the ECU. My ECU was bad so the IACV would stay closed (when it should have been open). When I was having problems with my car I would take my IACV off and reset it (plunger in), reinstall and the car would run fine. After a few minutes the engine would set it closed, stalling the engine. If I turned it off the ECU would automatically (incorrectly) close the IACV, causing it to cough and then ultimately stall.
Also, because the ECU was bad ... it would never throw an error code.
Let me know how it goes ...
So does anyone have a 93 sc400 ecu for sale? parts number 89661 24230??? lmk. I'm so close to selling my sc400 for $1800 but if the ecu does fix this problem, im definitely keeping it. crosses finger
ClubLexus Stories
Celebrating Lexus & Toyota from Around the Globe
8 Tips for Improving Your Hybrid or Plug-in Hybrid's Efficiency!
Michael S. Palmer
10 Best Lexus Models No One Remembers
Joe Kucinski
TRD Off-Road Premium: Best 2026 4Runner, Except This One Thing
Michael S. Palmer
Top 10 Lexus & Toyotas to Drive Before You Die!
Joe Kucinski
Top 10 Lexus/Toyotas With The LEAST 5-Year Depreciation
Joe Kucinski
Lexus LC500 Convertible Auction: A Preview of Rising Values?
Brett Foote
GX 550 vs TX 550: Best 3-Row Luxury Lexus Family Hauler
Michael S. Palmer
9 Best Lexus Models You Can Buy for Half Price (And 1 You Shouldn't!)
Joe Kucinski
2026 Lexus NX Buyer's Guide: Models, Features, Prices & More!
Brett Foote
Pole Position
Joined: Feb 2008
Posts: 389
Likes: 0
From: Fl
My 93 uses the exact same ECU as yours ... the 24230. I did my research and the costs/risks involved with the ECU are interesting. First, a new ECU will run you $1,500 at the stealership. You can find one on eBay for about $120 or so ... but there is risk involved with this option. I've bought two (2) ECUs off of eBay. I got lucky with the first as it immediately fixed my problem. I then found a killer deal on a second 24230 on eBay for less than $50 so I grabbed it. When I received it I immediately swapped out my known-good ECU for the spare and started her up. The car ran fine except the ECU would throw a traction control error all the time. The ECU was bad.
Try finding an ECU on eBay that allows for a return should it be found to be bad. I have a feeling that may be your ultimate problem. I am considering having my original ECU rebuilt so that I have a spare ... but again, there is a risk that this procedure will not fix the problem. My car has less that 55K miles on it, the ECU is pristine and still it went bad.
I've been told that two things kill the ECUs: bad capacitors and water intrusion.
Good luck.
Thread Starter
Pole Position
Joined: Jun 2009
Posts: 269
Likes: 0
From: Hawaii
My 93 uses the exact same ECU as yours ... the 24230. I did my research and the costs/risks involved with the ECU are interesting. First, a new ECU will run you $1,500 at the stealership. You can find one on eBay for about $120 or so ... but there is risk involved with this option. I've bought two (2) ECUs off of eBay. I got lucky with the first as it immediately fixed my problem. I then found a killer deal on a second 24230 on eBay for less than $50 so I grabbed it. When I received it I immediately swapped out my known-good ECU for the spare and started her up. The car ran fine except the ECU would throw a traction control error all the time. The ECU was bad.
Try finding an ECU on eBay that allows for a return should it be found to be bad. I have a feeling that may be your ultimate problem. I am considering having my original ECU rebuilt so that I have a spare ... but again, there is a risk that this procedure will not fix the problem. My car has less that 55K miles on it, the ECU is pristine and still it went bad.
I've been told that two things kill the ECUs: bad capacitors and water intrusion.
Good luck.
Try finding an ECU on eBay that allows for a return should it be found to be bad. I have a feeling that may be your ultimate problem. I am considering having my original ECU rebuilt so that I have a spare ... but again, there is a risk that this procedure will not fix the problem. My car has less that 55K miles on it, the ECU is pristine and still it went bad.
I've been told that two things kill the ECUs: bad capacitors and water intrusion.
Good luck.
No experience with these guys, but you can find ECU part numbers at the following link. They also sell remanufactured/refurbished ECUs:
http://www.siaelec.com/index.asp?Pag...S&Category=380
There are also a few companies on ebay that fix ECUs and offer a lifetime warranty on their work.
http://www.siaelec.com/index.asp?Pag...S&Category=380
There are also a few companies on ebay that fix ECUs and offer a lifetime warranty on their work.
Pole Position
Joined: Feb 2008
Posts: 389
Likes: 0
From: Fl
I would focus on the model number only and forget compatibility. If you currently have a 24230 in your car now ... then you should be safe replacing it with an ECU with the same model number ... no matter whether the car is an SC3 or 4.
Thread Starter
Pole Position
Joined: Jun 2009
Posts: 269
Likes: 0
From: Hawaii
nvm seller on ebay had it listed wrong. it was for the sc400. thanks guys
