p0120 Throttle Body Code Keeps Recurring After Cleaning

I have a 2001 Toyota Tacoma 4X4 V6 and I keep getting a recurring code of P0120 regarding the throttle body.

I recently cleaned the throttle position sensor and also did a seafoam treatment in the gas tank and in the motor oil reservoir also through the vacuum lines and sprayed carb cleaner in the throttle body and the check engine light was off for like 3 weeks but recently it came back on. However yesterday it had turned off for part of the day but now its back on.

Could it be that I need to replace the throttle position sensor? Or maybe I need to take the actual throttle body off and clean more completely and not just spray in past the throttle butterfly opening?

Any one have any experience with this issue that comes back after being solved for awhile?

Also can anyone recogmend a good model of front brakes and rotors for my truck my mechanic says I need new front brakes.

Thanks for any help


-PrerunnerSD
http://divesummit.com

 

Front brakes GO TUNDRA UPGRADE!!
Possible there's some gunk that got into TPS. I attached a file that might help.

 

Thanks a lot for the PDF this will provide a great insight.

Can you please explain what you mean by Tundra upgrade regarding the brakes. Do you have a model number or other info? Thanks

PrerunnerSD
http://divesummit.com

 

Tundra brake calipers/rotors "should" bolt on with little modification and are worth the cost and effort. The big issue is rim fitment... more than likely have to change to 16" wheels.

 

I had a TPS just fail at about 180,000 miles they do wear out .

New one from Toyota cured the Problem

 

Have any luck fixing this? I'm having the same issue on my 99 taco 3.4. Truck is tip top...cleaned the MAF, change air filter, cleaned throttle body, cleaned TPS. Haven't tried using fuel injector cleaner, but my check engine light keeps returning. I don't have the correct tools to know if my voltages for the throttle valve are operating correctly, so I'm going to now just try replacing the TPS with a new one. If that doesn't work it must be my connections or ECM?

 

Bump.

Similar issue and have tried same as @Dufus. I have an 01 with the 5VZ. Am curious if a new TPS is the answer...

 

Be nice to know just what code your pulling when you check .

THE TPS is simple to check a multi meter and code reader are pretty much a must have if working on OBD II vehicles the way I look at things.

 

I know P0120 is for the TPS but on my truck when the IAC gets dirty & starts sticking my truck will throw a P0120 code. I never get a code for IAC. I clean the IAC & it will be fine for 2-3 yrs. I know when when my IAC starts to get sticky cause my remote start won't work when cold cause of the IAC & cold idle.

 

^^^ excellant info. Other manufacturers coding for OBDII and the TPS system the PCM will monitor the TPS voltage, the MAF(mass air flow) and an MAP(manifold absolute pressure), if equipped, and compare the three. If the MAF and MAP change dramatically and the TPS shows the same voltage it will trigger a P0120. It makes sense, the TPS voltage IS below what it should be given the other 2 inputs. I can not locate in writting if the programming for the Tacoma uses the MAF reading with the TPS voltage to trigger a P0120 but your observation is leading me to believe so. If replacing the TPS doesnt solve the P0120 I would look at the MAF and clean it. If the voltage change in the TPS is not smooth and linear that will triggere a P0120 also. This can be checked with a multimeter but a graphing multimeter will show the spike instantly.

 

I do appreciate the replies. After some searching on TW I just opted to replace the TPS. It was ~70 bucks at NAPA (cheaper online, but I didn't want to wait). The took care of the CEL. 50 miles and still all good. Truck seems to be running better as well. More power, less lag and the throttle doesn't seem to be sticking (I gave the throttle body a good cleaning the night before last).

I'm unfamiliar with how to clean the IAC. Is it a part of the throttle body?
Thanks

 

it is bolted under the throttle body.

 

Thanks. It's attached with 4 Phillips screws, and it has a sensor, too, correct?

I gave that a good cleaning when I did the TB. It's hard to really get into it. Used a lot of sea foam deep creep and some q-tips.

 

I cleaned my TPS a second time with throttle body cleaner and it worked for me, no more check engine light. I opted to clean it again instead of paying $70 for a new one because I had nothing to lose at that point. Saved some money. No CEL for a month now (fingers crossed).

 

Interesting, curious, what do you clean on a TPS? It shouldn't be susceptible to getting dirty like a MAF or IAC. I use to work in automotive & I've not once ever had to clean a TPS.

 

I saw a little bit of dust in the crevices, other than that I just gave it a liberal spraying with throttle body cleaner and gave it ample time to dry. No brushing or anything. This truck was abused and an after-market air intake was in use before I got a hold of her. I believe a lot of excess debris was taken into the manifold. She's purrs like a kitten now though.

 

I bought my 01 with an aftermarket K&N air intake. Makes me wonder if I should try to find a stock air intake?

 

I'm definitely not a fan of K&N. I got a stock one at my local pick and pay for pretty cheap.

 

I'll have to look around. I asked the PO if he had any parts when I bought it and he said no. It's crazy to imagine he just threw them out!

 

If all else fails locally, Yoda Jims in Denver is sure to have one.