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Every time I fill up the tank, check engine light with P0125 code

Discussion in '3rd Gen 4Runners (1996-2002)' started by Striker7, Jul 29, 2022.

  1. Jul 29, 2022 at 12:10 AM
    #1
    Striker7

    Striker7 [OP] New Member

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    Hey so I own a 2000 4runner and recently, for whatever reason, each time after I refill on gas, the check engine light comes on and whenever I check it it reads error code P0125. However, the error goes away after using up to or less than a quarter of the tank. The coolant isn’t the problem as the level of coolant is fine when the code comes up.



    Would anyone happen to have any insight or experience with this kind of problem to know what could be causing it?
     
  2. Jul 29, 2022 at 4:55 AM
    #2
    Malinois38

    Malinois38 New Member

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    When you pump gas & it clicks, do you top it off with more gas? Or do you stop pumping?
     
  3. Jul 29, 2022 at 4:56 AM
    #3
    Striker7

    Striker7 [OP] New Member

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    I stop pumping after the the click
     
  4. Jul 29, 2022 at 6:08 AM
    #4
    negusm

    negusm New Member

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    P0125: Insufficient Coolant Temperature for Closed Loop Fuel Control

    Weird. This code points to an engine coolant sensor and not the fuel system.
     
  5. Jul 29, 2022 at 1:08 PM
    #5
    Striker7

    Striker7 [OP] New Member

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    Which is why I’m confused as to what could be causing the problem
     
  6. Jul 29, 2022 at 1:19 PM
    #6
    negusm

    negusm New Member

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    Did you verify the coolant temperature sensor is good?
     
  7. Jul 29, 2022 at 2:39 PM
    #7
    hvac guy

    hvac guy New Member

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    I know the code is for a coolant temperature sensor, but more than likely it's the front air/fuel sensor(1st o2 sensor closest to engine), had the same code on a older Tacoma years ago and ended up being the A/F sensor
     
  8. Jul 29, 2022 at 3:03 PM
    #8
    Overland WT

    Overland WT Grumpy Old Guy

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    It may be happening not because you are fueling, but the amount of time between stopping the engine, fueling and restarting. Your thermostat may not be opening correctly during the restart and you get that code. To test that theory, I'm guessing it takes 5-8 mins to refuel? Take your rig for a drive of maybe 15-20 mins to get proper engine temp, park at home on level ground, shut it down, and wait 8 mins to restart and see if you get it again?
     
    Hank69 likes this.
  9. Jul 29, 2022 at 3:19 PM
    #9
    hvac guy

    hvac guy New Member

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    From the manual:

    P0125 Detecting Condition
    After engine is warmed up, heated oxygen sensor (bank1 sensor 1) output does not indicate RICH (< or = 0.45 V)even once when conditions (a), (b), (c) or (d) continue for at least 1.5 mins:
    (a) Engine speed: 1,500 rpm or more
    (b) Vehicle speed: 25 (c) Throttle valve does not fully closed
    (d) 140 sec. or more after starting

    Trouble Area
    Open or short in heated oxygen sensors (bank1 sensor 1) circuit.
    Heated oxygen sensor (bank 1 sensor 1).
    Air induction system.
    Fuel pressure.
    Injector.
    Gas leakage on exhaust system.
    ECM

    If the voltage output of the heated oxyxgen sensor is less than 0.1 V, heated oxygen sensor circuit may be open or short.

    Trouble shooting Procedure.
    (a)Connect the OBD II scan tool or toyota hand held tester to the DLC3
    (b) warm up the engine to normal operating temp
    CHECK
    Read the voltage output of the heated oxygen sensor when the engine is suddenly raced. (Perform quick racing to 4000 rpm 3 times.
    Does heated oxygen sensor output a RICH signal (0.45 V or more) at least once?
     
  10. Jul 29, 2022 at 5:04 PM
    #10
    mousemeat

    mousemeat New Member

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    start checking sensors..
     
  11. Sep 27, 2022 at 9:58 AM
    #11
    gun smoke

    gun smoke New Member

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    are you overfilling your tank ? that can cause your evap system to react
     

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