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Aisan Throttle Body Tacoma 4Runner 4 Runner Tundra 2002-2004
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.
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.
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.
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.
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.
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.
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.
10-06-2017, 06:57 PM
Battery ground was a little loose
