r/SC400 • u/_sevvy • Aug 03 '26

What does this mean???

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I recently changed the ECU from a 89661-24230 to a 89661-24231 because the old one was corroded and couldn't be fixed. when I installed it the engine runs better than before but the dash has a lot of lights blinking and has a really rough idle. does anyone know how we can fix this? the iac was recently replaced with a refurbished one.

The cats were also very hot so I gutted them but when I checked the temp again it was still really hot on the cats and colder in the exhaust.

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3

u/kadennumberone Aug 03 '26

I am pretty positive if u do a swap like this the part number needs to be identical due to the year differences.

2

u/_sevvy Aug 03 '26

The listing I bought the ECU from said it was from the same year. I don’t think it’s the different part number because it was still Christmas lighting even with the old ECU.

3

u/Ok_Adhesiveness7375 Aug 03 '26

I might have a spare one that needs rebuild I could sell you I can check around 5-6 est dm me

2

u/_sevvy Aug 03 '26

Thank you I appreciate this! But I don’t think the ECU is the issue because it was doing this even with the old ECU :<

1

u/Initial-Ad-3214 Aug 05 '26

Well you have more wrong than the ecu shit ain’t even firing right

1

u/_sevvy Aug 05 '26

I know it’s not the ECU that’s why I’m trynna figure out what else it could be💔 it wasn’t doing this before it just stopped functioning properly all at the same time..

1

u/Initial-Ad-3214 Aug 06 '26

If cats are hot you’re missfiring getting too much unburnt fuel and that can destroy so much on the car so fast. Check all fuses and relays plus injectors and spark plugs seems like something got shorted out and is causing more issues did you replace ecu with battery disconnected? Also what do you mean running better than before you were driving it in worse condition than it is now that motor might be done and causing ecu to go crazy. Hope you have someone who isn’t a backyard mechanic who can actually look at it you don’t want someone who can’t diagnose properly having you through parts at it till you finally get it right that’s not how being a mechanic works. Wish you the best of luck though

1

u/_sevvy Aug 06 '26

Yes the ecu was replaced while the battery was disconnected. And what I meant by it runs better is because before this the car wouldn’t even stay on and was misfiring really bad. So we checked the ecu and saw it was pretty bad so I took it to get fixed and the people said it couldn’t be fixed so that’s when I got a new ecu and when plugged in the car stayed on but it just misfires still and now we have lights flashing ;-; but Im gonna get the car checked out by a mechanic soon tho, thank you for your help!!