Urgent help needed with TPS!!
12-10-15, 02:50 AM
#16
the P1120 , which refers to the APPS , is the sensor on the part which the trottle cable pulls.
check this thread .. https://www.clublexus.com/forums/per...ccelerate.html ( there is a link there from amazon so you see the picture )
The Idle Control Air Control Valve is what control the air into the intake manifold . If the Throttle Control Motor which is referred by your error code P1128 is bad .. then idle suffers.
You said you already have replaced your TPS (referred by error code P0120) and it didn't resolve the issue cause you still have the same idle problems and still having that error code .
In my opinion, as I have mentioned in my previous post .. I maybe wrong but I believe it is your Throttle Control Motor which is bad.
why ? you said ..
a) you are getting error code P1128
b) at start up you need to press the accelerator to get it going and if you don't keep pressing it , dies out.
That is exactly what the IACV ,in your case which is a VVTi engine, throttle control motor .does.. regulate the air on the intake manifold.
c) you are still getting the P0120 (TPS) error code even if you ALREADY REPLACED the TPS.
d) now, the APPS may also be bad but unlikely cause , your system is throwing the P1128 and P0120 at the same time .
e) the P1128 error code can make it appear that you also have a P0120 and P1120 error codes even if those parts (TPS , APPS) are not really bad.
check this thread .. https://www.clublexus.com/forums/per...ccelerate.html ( there is a link there from amazon so you see the picture )
The Idle Control Air Control Valve is what control the air into the intake manifold . If the Throttle Control Motor which is referred by your error code P1128 is bad .. then idle suffers.
You said you already have replaced your TPS (referred by error code P0120) and it didn't resolve the issue cause you still have the same idle problems and still having that error code .
In my opinion, as I have mentioned in my previous post .. I maybe wrong but I believe it is your Throttle Control Motor which is bad.
why ? you said ..
a) you are getting error code P1128
b) at start up you need to press the accelerator to get it going and if you don't keep pressing it , dies out.
That is exactly what the IACV ,in your case which is a VVTi engine, throttle control motor .does.. regulate the air on the intake manifold.
c) you are still getting the P0120 (TPS) error code even if you ALREADY REPLACED the TPS.
d) now, the APPS may also be bad but unlikely cause , your system is throwing the P1128 and P0120 at the same time .
e) the P1128 error code can make it appear that you also have a P0120 and P1120 error codes even if those parts (TPS , APPS) are not really bad.
Last edited by gerrb; 12-10-15 at 09:25 AM.
12-10-15, 05:54 AM
#17
Intermediate
Thread Starter
I'm going to get a used throttle body from the junkyard or eBay and see how that goes.
Traction Control Motor? Did you mean Throttle Control Motor? I have no traction control on my car.
Traction Control Motor? Did you mean Throttle Control Motor? I have no traction control on my car.
12-11-15, 03:53 PM
#21
Intermediate
Thread Starter
P1400 Sub-Throttle Position Sensor Circuit Fault
P0120 Throttle/Pedal Position Sensor/Switch "A" Circuit Malfunction
I'm not sure on the fixes, for P0120 the recommended is to change the TPS, but many members here and on toyota forums have been reportedly saying that the TPS usually doesn't go bad, it's the APP(Throttle Lever). As for myself, I replaced my TPS yet the same code showed up. Cleaning the throttle body didn't help either. I'm getting a used Throttle Body to see if that fixes the problem.
Don't have any info on P1400.
P0120 Throttle/Pedal Position Sensor/Switch "A" Circuit Malfunction
I'm not sure on the fixes, for P0120 the recommended is to change the TPS, but many members here and on toyota forums have been reportedly saying that the TPS usually doesn't go bad, it's the APP(Throttle Lever). As for myself, I replaced my TPS yet the same code showed up. Cleaning the throttle body didn't help either. I'm getting a used Throttle Body to see if that fixes the problem.
Don't have any info on P1400.
12-11-15, 05:19 PM
#22
BlackIron - what car and year model do you have ? Car problems might be different in yours . Your car has a traction control motor on the throttle body ...
Both error codes you mentioned refers to TPS that are both on the throttle body .
P1400 - tps controlled by the traction control motor
P0120 - tps controlled by your accelerator cable
You may or many not have an APPS (Accelerator Pedal Position Sensor) if your car is not VVTi .
Both error codes you mentioned refers to TPS that are both on the throttle body .
P1400 - tps controlled by the traction control motor
P0120 - tps controlled by your accelerator cable
You may or many not have an APPS (Accelerator Pedal Position Sensor) if your car is not VVTi .
12-12-15, 04:14 AM
#23
Pole Position
its been driving me crazy because the car would stall got a new ecu and fixed it now with the new ecu it throws like 3 TPS circuit codes but runs fine just extremely rough idle and will not pass 2100 RPMS in drive. sorry i dont mean to hijack the thread just a similar problem. shes a 96 with trac then the IACV then the actual TPS itself when the ignition is turned on i have ALOT of clicking for 3-7 seconds close to the trac. i have been looking for the pedal sensor to no avail. she isnt VVT-i
12-12-15, 04:22 AM
#24
its been driving me crazy because the car would stall got a new ecu and fixed it now with the new ecu it throws like 3 TPS circuit codes but runs fine just extremely rough idle and will not pass 2100 RPMS in drive. sorry i dont mean to hijack the thread just a similar problem. shes a 96 with trac then the IACV then the actual TPS itself when the ignition is turned on i have ALOT of clicking for 3-7 seconds close to the trac. i have been looking for the pedal sensor to no avail. she isnt VVT-i
The clicking you hear near the trac motor is more likely the IACV .
You say
a) it will not pass 2100 rpms
b) throws different TPS error codes
that for me , I maybe wrong though , points to the IACV .
12-12-15, 07:39 AM
#25
Pole Position
thanks for your help man but i decided im buying another SC theres a 95 close by for sale. i cleaned the IACV thoroughly and the TB but did not unbolt it. i changed the TPS itself and the clicking is the small butterfly that the trac sensor is on opening and closing once the key is in the ON position. what is strange that with the previous ECU is would stall out but still shift, after the second has been installed both original and replacement ECU cannot exceed 2100 RPMs. the old and new TPS sensors themselves are not being read by either computer the TPS signal on my ob2 reader stays at 0% even at 4300 rpm i will post a video and pics below as a reminder replacing the two sensors and cleaning the IACV have done nothing for me
Last edited by BlackIRON; 12-12-15 at 01:34 PM.
12-16-15, 12:52 PM
#26
Intermediate
Thread Starter
UPDATE: So I replaced my entire throttle body and started it. Started absolutely fine and also cleaned the TB a bit before installing. Drove it for 15 minutes around the neighborhood, so far no CEL(Check Engine Light) and the accelerator seems to be working fine too.
I did notice that my car goes very low RPM after 10 seconds in drive if I'm stopped. My car will start shaking and it feels like at any moment it is about to die out. I think this is a different issue, searching through the GS and SC forums it may be O2 Sensors, a bad battery, vacuum leak, or even bad gaskets. I hope it's an easy fix. I will say this, I was getting this problem before as well but it wasn't as severe. Not sure what it could be though.
I really want to thank you all for helping me out and one major headache is out of my way, since this is my only vehicle and it's a DD.
If anyone has any insight on what to check or what it could be, please chime in.
I did notice that my car goes very low RPM after 10 seconds in drive if I'm stopped. My car will start shaking and it feels like at any moment it is about to die out. I think this is a different issue, searching through the GS and SC forums it may be O2 Sensors, a bad battery, vacuum leak, or even bad gaskets. I hope it's an easy fix. I will say this, I was getting this problem before as well but it wasn't as severe. Not sure what it could be though.
I really want to thank you all for helping me out and one major headache is out of my way, since this is my only vehicle and it's a DD.
If anyone has any insight on what to check or what it could be, please chime in.
12-16-15, 01:01 PM
#27
^^^^ Glad things are better . It must have been the IAC motor on that throttle body in your case .
check your throttle stop screw . It might be adjusted too loose... tighten it a bit to raise idle.
an O2 sensor should throw a CEL .. and give you an error code most of the time.
check your throttle stop screw . It might be adjusted too loose... tighten it a bit to raise idle.
an O2 sensor should throw a CEL .. and give you an error code most of the time.
12-16-15, 04:11 PM
#28
Intermediate
Thread Starter
What's the throttle stop screw?
Going through the GS400 forums I stumbled on some thread where a similar issue was occurring. Members said that sometimes your O2 sensor can get bad but it won't show a CEL, do you think that's possible?
Also the OP from that thread fixed his problem by replacing the battery.. , might give that a shot too.
My temporary solution before was to keep the AC on for the idle rpm to stay up.
Going through the GS400 forums I stumbled on some thread where a similar issue was occurring. Members said that sometimes your O2 sensor can get bad but it won't show a CEL, do you think that's possible?
Also the OP from that thread fixed his problem by replacing the battery.. , might give that a shot too.
My temporary solution before was to keep the AC on for the idle rpm to stay up.