P1128 Throttle Control Motor Malfunction (1 Viewer)

[landcrusierfan]

I’m just here to give thanks to maingear and testify that cleaning the ECU as a first step fixed this for me. Hell, i’d recommend everyone clean their ECU pre-emptively.

Full story: Sunday I had the wife and kids loaded up ready to go for an adventure, after LC had been mostly sitting a few weeks. We made it about a mile down the road, and suddenly no power at all and had to coast off to the side of the road. The CEL would’ve been lit right before it died if I didn’t already have the CEL lit for other reasons. Well after figuring out it’d go if I mashed the gas all the way down, i limped it home and switched cars. Ran codes later, new P1128. Tried cleaning throttle body. Throttle operated ok by hand. Tried drying wet spot with big fan on driver floor a couple days, as it could relate to mystery relays on drivers side. But None of that helped. I could take it up and down our road about a mile before p1128 and dead again. After reading here, went ahead and pulled ECU, which was actually sparkling clean on the inside. No sign of dirt, but I still sprayed it down with QD electronic cleaner really well, and dried off with compressed air. It fired up easy, and no problems since. I’ve driven it back and forth to work 3 days now, hoping this is solved with no money spent.

Hi there, did this solution fix this issue for you? I have a 1999 land cruiser with 131k and this issue popped up today. I have already replaced the TPS. Any advice would be great!

 

[KFunk740]

Hi there, did this solution fix this issue for you? I have a 1999 land cruiser with 131k and this issue popped up today. I have already replaced the TPS. Any advice would be great!

Sure did, it's been a year of regular use since then and no issues at all.
If the throttle body looks clean and moves fine, I wouldn't suspect any issues with it. I'm fairly used to fixing electronics, so popping out the ECU board didn't scare me much, but it's really no big deal. Take it out and a few screws you can take it apart, clean it off good with QD electronic cleaner, then make sure it's good and dried off. I used some compressed air because I didn't feel like waiting. Then put it back together and in, and should be fine. In the worst case, you're really dumb and screw it up, you can get another ECU for like $500 to $1K (may be cheaper and easier from a guy on the forum, not sure). But you may be on the path anyways toward getting a new ECU if the TPS and throttle body are fine, so what's it hurt to give the ECU a cleaning and try it?

 

[landcrusierfan]

Sure did, it's been a year of regular use since then and no issues at all.
If the throttle body looks clean and moves fine, I wouldn't suspect any issues with it. I'm fairly used to fixing electronics, so popping out the ECU board didn't scare me much, but it's really no big deal. Take it out and a few screws you can take it apart, clean it off good with QD electronic cleaner, then make sure it's good and dried off. I used some compressed air because I didn't feel like waiting. Then put it back together and in, and should be fine. In the worst case, you're really dumb and screw it up, you can get another ECU for like $500 to $1K (may be cheaper and easier from a guy on the forum, not sure). But you may be on the path anyways toward getting a new ECU if the TPS and throttle body are fine, so what's it hurt to give the ECU a cleaning and try it?

Thank you for your response it’s very helpful. Did you replace the TPS on your vehicle before this issue popped up? I had the TPS P1121 code pop up last year in January. I went to Autozone and when they read the code, I bought the TPS from them because the Toyota dealer would take a week to ship. Well after 5 months the same issue and code popped up, truck went into limp mode. So I got a replacement TPS from Autozone. I don’t trust the cheap Chinese parts that they sell after that. Well now it’s been five months and less than 5,000 miles and the truck went into limp mode yesterday but the code they read is P1128. But I have a suspicion that it may be that crappy TPS I got from them, any thoughts? My LC has 131,000 miles.

 

[KFunk740]

Thank you for your response it’s very helpful. Did you replace the TPS on your vehicle before this issue popped up? I had the TPS P1121 code pop up last year in January. I went to Autozone and when they read the code, I bought the TPS from them because the Toyota dealer would take a week to ship. Well after 5 months the same issue and code popped up, truck went into limp mode. So I got a replacement TPS from Autozone. I don’t trust the cheap Chinese parts that they sell after that. Well now it’s been five months and less than 5,000 miles and the truck went into limp mode yesterday but the code they read is P1128. But I have a suspicion that it may be that crappy TPS I got from them, any thoughts? My LC has 131,000 miles.

Well, it may be unrelated, but I wouldn't want any Autozone electronic junk on my cruiser, and would get an OEM replacement. I've had too many autozone electrical parts fail for no good reason. I went through like 3 or 4 voltage regulators for my Datsun from them, and several alternators.

I don't know that a screwed up TPS could trigger a P1128, though. I'd still clean the ECU, even if it were just pre-emptive. Going into limp mode and having absolutely no power suuuuuuucks.