Question about 2002 Toyota RAV4

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Rav4 2002 model running like there is something restricting it rough idle huge flat spot on acceleration then slowly accelerates i have been told that it is the 2 o2 sensors underneath after cat by a mechanic as there are 4 on my model. I didn't think o2 sensors would make any differance in the drivability of the car, could there be another solution as they want to charge $386 each sensor and they still don't know if it will fix the problem. They put there computer on it and it came up with the 2 codes relating to the 2 o2 sensors but there still not sure. any help would be great Cheers pas.

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  • pasqualiwho Jun 17, 2009

    Cheers for that sorry couldn't get back at work,i'll try that tonight see if it improves godd to see someone knows there stuff cheers buddy pas from Oz.



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171 Lean mixture
420 catalytic converter inefficient
1130 Air Fuel sensor range
1133 air fuel sensor

All those codes mean is theat the system is running lean and suspect the O2 sensor is bad.

I would like to know thw engine, miles and tranny type.

It means the Transmission which is attached to the engine that turns the driveline meaning the wheels.

P0171 Lean Mix can be caused by the following:

* Low fuel pressure due to a weak pump or leaky fuel pressure regulator. (use a fuel pressure gauge to check fuel pressure at idle)

* Dirty fuel injectors. (try cleaning the injectors)

* Vacuum leaks at the intake manifold , vacuum hose connections or throttle body. (Use a vacuum gauge to check for low intake vacuum)

* Leaky EGR valve. (Check operation of EGR valve)

* Leaky PCV Valve or hose. (Check valve and hose connections)

* Dirty or defective Mass Airflow Sensor (MAF). (Try cleaning the MAF sensor wires or filament with aerosol electronics cleaner. Do NOT use anything else to clean the sensor, and do not touch the sensor wires)

P1130 Heated oxygen sensor

Worrry about the F/pressure later. Test the throttle position and MAP sensor by following the book procedures.

RAV4 TPS checks

(1)Fully Closed VTA & E 2200-5700 ohms

Fully Open VTA & E 22000-10,200ohms
VC & E 22500-5900ohms
(1)Apply vacuum to throttle opener before checking TP sensor.

In the book find the illustration of the throttle opener and do below.


Start engine and warm engine to normal operating temperature. Ensure idle speed is within specification.

With engine idling, disconnect and plug vacuum hose at throttle opener. Increase engine speed to 2500 RPM. Release throttle and note engine speed.

Engine speed should be 1300-1500 RPM with electric cooling fan off.

If engine speed is not within specification, loosen lock nut (if equipped) and rotate throttle opener adjusting screw until correct engine speed is obtained. Tighten lock nut (if equipped). Reinstall vacuum hose on throttle opener.

You might have a dead spot on the TPS or a problem with the MAP sensor

Do you have any OBD2 code/s

I think Rav4 even though is an inline 4 banger ..but it has 2 upstream and 2 dn stream O2 sensor on most u he put after market O2 sensor instead of a wide band air fuel ratio sensor .....thats where the bucking came from....

Could be it they operate differently in heat plus its got its own relay within the circuit that operates at the same time as the EFI relay.

wide band air fuel sensor use amp to detect rich & lean condition while voltage stay pretty much constant .....traditional O2 sensor use voltage to reflect the A/F ratio ..but not accurate just rich & lean.......but most of the wide band crapping out are becuz of the heating element that can be chk with a low amp probe

The Wide Ratio A/F sensor it operates @1200F deg compared to the narrow @ 600 it changes its 8 amps. output to the amount of O2. At stoichimetry there's no current flow and the voltage put out by the detection circuit is 3.3volts. At rich mix it produces a negative current flow then voltage goes below 3.3volts. At lean mix positive current flow,the detection circuit will produce above 3.3volts. With the narrow ones its at 0.45volts.

Give the throttle body a good cleanup with carb cleaner and it should be ok.

Posted on Jun 17, 2009

  • mohammed marika thambi
    mohammed marika thambi Jun 17, 2009

    Final respond: Get it scan for code/s I've
    allready given you a lead, however you have not responded whether
    you're checking it and coming back with the results-In my opinion this
    problem is beyond your control-therefore you need a pro to fix the
    problem-again its not DIY thing. Its really hard to assist when am not
    there looking at it in different angles/approach. I'm sorry my best
    wasn't good enough.

    CTS/TPS/MAF or Airflow meter??????????--could be also clogged-up exhaust.



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