stpete

I'm new to the forum after being given a 1998 GS300. I recently had the same problem as the OP with codes P1120, P1120 with both VSC lights and check engine (198K miles). The car started off with some random "throttle off" conditions, where the car would just suddenly act like I let off the accelerator. Then it would go again. That happened randomly for a couple weeks. It would happen a few times in a row, then not again for a couple days. Finally went into limp mode. Restarts would sometimes fix it for a while, but it would wind up back in limp mode.

I replaced the Pedal sensor (part 22060-46010) based on info in this thread. After a couple days it seems to be fixed. Local dealer wanted about $400 for the part and didn't have it in stock. So I ordered it new from a seller on ebay for $270 delivered and had it in 2 days anyway. Thanks everyone!

az-dave

Nice! :-) Another helped

4doorscore

subscribing as I am having this problem rn! thanks for the info.

davinciii

Wanted to add my problems with my gs400

problem started two days ago. started up car idle rough and died over and over. finally i got it to drive out of parking lot and it drove fine on freeway.
next day at friends shop fixed 2 cracks in vacuum hose and it drove fine home..

hour later it would not idle in my parking lot. just starts dies.. If i press the gas pedal in all the way to engage the cable it dies...

took throttle body off and replaced tps since i had lexus close to me and ohms looked outta spec. put it back together.. car now starts.. hunts for idle then dies.

there is no throttle response from pedal. still if i engage the cable it dies instantly.

the codes i have pulled are

p0100 mass or volume aire flow circuit A

p0110 intake aire temp sensor 1 circuit

p1125 throttle control motor cir malfcunction

p1128 throttle control motor lock malfuncion

p1345 vvt sensor camshaft positoin sensore cir malfunction bank 1


Now im reading about ohm out the maf.. and the throttle control motor... the apps (located on the throttle body where the cable is) and the pedal positoin lever assembly (located on the pedal)

what i really need is someone who can verify for me the correct pins. i have seen pics with the pin out listed but sometimes its for a ls400... or gs300. im looking for gs400 picture of the pinouts i need to test. Not just the code name of the pins. b/c im getting mixed up trying to ohm them out.

burny

almost 3 months to the day I replaced the TCM. Today Chek engine and VSC lights came on and acceleration was horrible. Car ran like new for 3 months. Is this just a bad motor or could something be causing the motors to fail? Will Sewell's repace it after 3 months? Code P1128. I have disconnected it and checked ohms. Got 5.6 ohms.

pitchblaq

Hi guys, I just discovered something that I have not seen mentioned for our limp mode issue. My Air Intake Resonator/Cleaner has crystallized and formed fractures along the bottom edges that let's significant air leak out, which causes vacuum leaks. I was able to examine it and sealed it with metal exhaust tape. I didn't think to take pics, but will get a new one from L-Tunes fot 147.00. I will keep you guys posted. Its been running perfect for 5 days now. No misfire or accel delay at all. The car feels back to new. This intake is located between the throttle body and MAF.

burny

So my TCM, TPS, APPS all have been replaced. The code is P1128 which is TCM is locked. The car is in limp mode from time it starts. I undid battery today for about 30 minutes to rebuild a door lock actuator. Car got the CEL and VSC light as soon as I tried to drive it. Idling is also much higher than it has been. I set it at 600 rpm when i did the TPS 3 months ago. It is now 1500 to 2000? Where should I start?

pitchblaq

Make sure you get a voltage reading of .65v to .75v at the 2nd from the top wire and bottom wire on tps with the key in ignition set to on. Also I found that my Air Intake Resonator had crystalized and micro fractures at the edges on the bottom, which caused limp mode and the same vsc codes. The Air Intake Res is located between MAF and throttle body. Its been 5 days and my 03 gs300 has never ran better. I used metal exhaust tape for temp patch until I get a new one from L-Tune for 147.00. Also your tps install should be facing at 5 o'clock and then rotate it to about 3 o'clock. At that point do your voltage adjustments by rotating the tps left or right.

burny

thanks for response. I'll double check again for those cracks you mentioned. but did look 3 months ago when I cleaned everything and replaced the sensors. I am really thinking this might be the ECU. there is no power on take off and this is different that what I experienced in limp mode. Also idling changed drastically after the battery was disconnected for a while. If ECU was bad would it be able to throw a P1128 code or any code for that matter?

pitchblaq

Check and make sure the tps is getting correct voltage and installed correctly. I remember when I installed tps, I made the mistake of having the connector facing up and turning clockwise to line up screws, when it should have been facing down and turn anti clockwise to line up screws.

burny

It was the 3 month old TCM. The ohms did't check out so swapped one out fro a working car and all codes were gone. Now to see what I can work out with Sewell's on a replacement. I'm guessing they won't budge.

pitchblaq

Good deal man. Glad to hear you got it up and running correctly.

burny

I really believe the heat generated from the car is frying these Throttle control motor harnesses over time. The TCM harness is especially vulnerable to extreme heat due to its location. There is a notch on the throttle body that you have to hang the TCM harness before putting the screw into it. If you replace the TCM and forget to take the hang plate from the harness you will not be able to mount the harness as designed. Just a FYI for you.

pitchblaq

Check this thread I posted a few days ago, I think it may resolve your issue. It's worth a try.

Hi guys, I just discovered something that I have not seen mentioned for our limp mode issue. My Air Intake Resonator/Cleaner has crystallized and formed fractures along the bottom edges that let's significant air leak out, which causes vacuum leaks. I was able to examine it and sealed it with metal exhaust tape. I didn't think to take pics, but will get a new one from L-Tunes fot 147.00. I will keep you guys posted. Its been running perfect for 5 days now. No misfire or accel delay at all. The car feels back to new. This intake is located between the throttle body and MAF.

pitchblaq

It's been a week now and my 03 GS300 is purring like a kitten after I sealed the cracks in my (Air Intake Resonator). I'm not saying that this is the resolution to all limp mode issues, but I have seen some threads, where they replaced all parts (tps, apps, throttle motor, etc....) and it did not resolve issue. It's worth a look guys, thrust me on this one.