I recently purchased a 1999 Toyota Land Cruiser with 316,000 miles, the owners said it was running driving fine until it sat a few months and now it goes into limp mode after driving 1-2 miles. Once it sits overnight it goes out of limp mode and runs amazing, good throttle response, but drive it a mile or 2 and back to limp mode. The previous owners just did timing belt, water pump, fuel pump, fuel filter, new battery cables, and a new radiator. I have so far cleaned MAF, took the throttle body off and cleaned it, I've adjusted the throttle cable to see if it made any difference, cleaned all the connectors to the TB. and my next plan of action was to replace the wiring harness to the throttle cable housing. Someone has previously done a very trash job rewiring a non OEM plug to it so I figure thats a good place to start. Anyone else had a similar issue? Any ideas where else to check? The only code I'm throwing is P1129.
Limp Mode Issues 1999 Land Cruiser
- Thread starter Camaron
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I'd start with that, do better/soldered connections and see if that resolves it.
- Thread starter
- #5
its not a flashing CE light just a constant, like I said it goes away after it sits overnight or I can unhook the negative battery cable for 2 mins and it resets it, then right back to it after a mile or two drive... the only code I have is P1129 which is "electric throttle control system malfunction"
- Thread starter
- #7
So before I made a post and said I had a P1129 code and it was probably related to the wiring job the previous owner had done so I took it to Toyota to confirm and they said that the wiring was probably the root of my issue… so we cut the wires, stripped em, saudered them together, heat shrank them, then taped it. Now I still have the P1129 code but I also had a P1126 code come up as well. That points toward it being the electrical clutch circuit.. but Toyota told me today if rewiring that didn’t fix it then it needed an ECM… kinda at a loss of where to go next for reference it’s a 1999 Land Cruiser
before
after stripping, saudering, heat shrink, and taping over it.
the new code after re-doing the wiring
I checked my OHM readings to the TPS with this chart and found that the readings for fully closed were all way too high and the readings for fully opened were all too low so now I'm lead to believe I need a new TPS... any help would be greatly appreciated.
before
after stripping, saudering, heat shrink, and taping over it.
the new code after re-doing the wiring
I checked my OHM readings to the TPS with this chart and found that the readings for fully closed were all way too high and the readings for fully opened were all too low so now I'm lead to believe I need a new TPS... any help would be greatly appreciated.
This might be a stupid question but has anyone unplugged that connection and checked all the pins? The only reason I don't think its the ECU is because you say you can drive a bit and then the CEL comes on. Going along with the light though, it might be worth seeing if it goes from a pending code at startup to a confirmed code after driving.
No idea if those codes work that way, but that method of checking has helped me troubleshoot some stuff in the past.
No idea if those codes work that way, but that method of checking has helped me troubleshoot some stuff in the past.
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- #9
do you mean the pins on the plug itself? I checked the TPS side of the plug but not the plug itself... I didn't know there was a reading chart for it, however like I said the TPS side every reading is wrong.
I keep messing up reading peoples posts, but I was meaning what you checked on the TPS. My bad.
I would agree with you that if what you are reading on the TPS side isn't giving the right resistance you have an issue with the TPS. Looks like its a sub 100 dollar part, I'd say its worth it to just pick one up and see.
Its crazy to me that toyota looked at this and said ECU when you aren't getting the right readings off the TPS. Dealerships are wild sometimes.
I would agree with you that if what you are reading on the TPS side isn't giving the right resistance you have an issue with the TPS. Looks like its a sub 100 dollar part, I'd say its worth it to just pick one up and see.
Its crazy to me that toyota looked at this and said ECU when you aren't getting the right readings off the TPS. Dealerships are wild sometimes.
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- #11
im beginning to think it might just need a new TB, that's the 2nd option Toyota gave after saying it'd be the ECM but I just cannot see it being a bad ECM when literally everything on the vehicle functions as it should.
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- #12
1999 LC, 4.7 had a limp mode issue. So if you check my other threads it started with my faulty wiring to the throttle cable housing, we redone the wiring, saudered it, and heat shrinked it correctly.. Limp mode because less prevelant but would still happen every time you'd drive it eventually... after rewiring the next code was P1129 (electric throttle control system malfunction) took it to Toyota and they said it needed a new throttle body.. ordered a brand new OEM throttle body, replaced it, ran it to town and drove like new then right back into limp mode. Now it has a P1126 and P1128 code.. still going into limp mode
Maybe check TPS/APPS - Throttle Position Sensor, Accelerator Pedal Position Sensor.
- Thread starter
- #14
I don't have either of those codes but yes I get no pedal when it does it and only power available when floored like you said.. however the entire throttle body TPS and the motor is all new I just ordered the entire thing so it shouldn't be TPS or APPS should it?Maybe check TPS/APPS - Throttle Position Sensor, Accelerator Pedal Position Sensor.
I don't know. Haven't dug into it, just knew enough to suggest something seemingly associated.
Merged your 3 threads on this so all the info and backstory is in one place, no need to start a new thread each time.
Didn't know you can just add to a thread you've already started? Anyway, I would check further into the wiring, if the PO did some bad soldering job in the first place, why were those wires cut and are there other wires in that harness cut? Then, I'd either get/borrow/go to a shop with a better diagnostic reader that can do real time data and see what that shows for the throttle, MAF, o2 sensors, etc.
GTV
SILVER Star
He can merge them. He is a moderator.