Manufacturer Aisan
Throttle body part Number: W0133-1742371

2001 4runner had P1125 trouble code. Errors were from a failing throttle position sensor that was no longer available from Toyota. After trying three different 4 prong TPS I gave up and lived with the issue, motor stumbling.

Today, I received a throttle body from Ebay. Cost, was about $800 including shipping and a 30 day warranty. Near $300 savings compared to dealers. Within 2 minutes the computer learned idle. I'll update if there is a problem in the next month.

 

There was a very brief (less than 2 seconds) hesitation. No "check engine" light or trouble codes were produced.
Happened after I filled up with gasoline. Drove again with no issues. Perhaps it's the winter gasoline mix.

 

Hesitation from 20 to 55 mph. Trouble code P1125. Engine light was briefly on.

 

2001 4runner doesn't have a pedal sensor. The throttle body is controlled by cable. Also P1125 is for throttle control motor. 2001 4runner doesn't have that either.
The problem is the connection from the throttle position sensor on the throttle body to the ECU. There are 4 wires as seen in the diagram provided by EatonKyleH
at http://www.toyota-4runner.org.

 

Two days and no hesitation no new trouble codes since I used dielectric grease on the throttle body sensor connectors.

 

Good work on the troubleshooting. Was about to say its likely electrical. These engines are due for all sorts of electrical contact cleanings it seems. Makes sense to do first before replacing what could otherwise be a still viable unit.

 

Autumn drive didn't go well.

Engine light blinked several times with no code.

Engine stumbled at various speeds. UNTIL, giving it
3/4 pedal. Then..

VSC/OFF VSC/TRAC and engine light illuminated.
Trouble code P1125 reappeared.

Now, throttle has a sour spot about 1/3 pedal distance.
Deactivating OD makes the 4runner stutter less.

Also heard, what might be a relay clicking under the dash during
some off of the engine stuttering.

.. check voltage from TPS during throttle.
.. check ECU connector
.. check cold idle, it was too high 1,500 RPM.

 

I think you misunderstood. The 2001 4Runner 5VZ-FE IS throttle-by-wire; it does have a pedal sensor, and it does have a throttle control motor. The cable referred to in the FSM excerpt is a "limp-home" back-up that is only used when the ECU senses a fail and shuts down the throttle by wire. You can confirm this by flooring the accelerator with the key off. The cable will only open the butterfly partially. On a non-TBW 5VZ-FE, such as on 1999-2000 4Runners, the butterfly will open fully doing the same thing. The 2001-2002 TBW needs the throttle motor in action to fully open the butterfly.

 

Thanks Durk!

Validated drive by wire with cable backup.
Validated throttle motor, used ohm meter and it comes really close to my old one.
Checked the throttle motor connector and pins. Applied dielectric grease.

Battery ground was a little loose. Snugged it up.

Ordered ODBII device to link to my laptop for data logging.
Will revisit this when I have a log to show.

 

2001 4runner with v6 doesn't have an accelator pedal sensor. (See circled pedal stop pic below)
ECU takes throttle position from the throttle position sensor.
ECU is located below the passenger side air bag, above the glove compartment.
10 mm bolts, Philips screws.

2001 4runner V6 accelerator pedal stop.

 

The sensor is not on the pedal, it's on the throttle body. It's technically called an Accelerator Position Sensor and is not a separate part, and is on the radiator side of the TB where the cable comes in. The Throttle position sensor is on the firewall side. The cable direct linkage to the butterfly is just for limp-home. It does provide input to the Acceleration Position Sensor, which, together with the TPS, is how the ECU controls the butterfly motor.

 

Tested impedance wire connection to ECU from accelerator sensor connector using multi meter. No breaks in the circuit.
Tested pins 1 and 2 of the accelerator sensor. Impedance increased as the sensor was manually turned.
Pins 3 and 4 held the same resistance while manually turned.

Tested old accelerator sensor.
Pins 3 and 4 resistance increased as the sensor was turned.

Swapped old part into new throttle body.

Ran 4runner for 10 minutes in closed loop.
P1125 code cleared.

Short term trim reacting to throttle.

No trouble codes seen.

Time will tell if these was a fix.

 

No issues.

 

Twice, hesitation at or around 50 mph.
No codes.
Hesitation goes away when O/D is disabled.

Once, reduced power, like it was on limp mode.
Cleared on it's own after a few seconds.
No codes were produced.

 

Code P0300 Multi misfire present
Watched live data and code p0303 showed up.

Diagnostics on Saturday.