Toyota Camry P0171 P0125 P1135 Emission Failure Codes

Air Fuel Ratio Sensor

Many codes, one problem.

Oxygen sensor failures are common to all cars not just Toyotas. But Toyotas present different codes that you might not expect for this common problem.

When a car has the 300 dollar oxygen sensor (California emissions) we call it the air fuel ratio sensor. Check with Toyota dealer by VIN number to verify which type you have. An air fuel ratio sensor is not interchangeable with a regular oxygen sensor even though they look the same.

P0171 System Too Lean. This code will set when an air fuel ratio sensor gets lazy.

P0125 Insufficient Coolant Temperature For Closed Loop. Sounds like a bad thermostat right? No, on Toyotas its our air fuel ratio sensor taking too long to get active.

P1135 Air Fuel Ratio Sensor (Bank 1 Sensor 1) Heater Circuit Malfunction. The heater in the air fuel ratio sensor is drawing too much or too little current.

Amazon sells the Bosch 13733 air fuel ratio sensor for about 113 dollars which is the lowest price I have been able to find anywhere. This sensor works well on these cars.

 

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Comments Welcome! 2 comments

lexusclass2 4 years ago

LOL... i call myself trying to clean all my wiring harnesses with eletronic cleaner spray after doing so my CEL came on and i assume it was a hardness i miss to connect after 4 long days looking under the hood, reconnecting all harnesses, cleaning my intake and MAF disconnecting the battery, changing my thermostat (big mess)and hours researching code p0171, p0153, p0125 light still came on was going to give up and take it to the shop....WELL READING THE THREAD AND ABOUT 10 MINS WITH 7/8 WRENCH CHANGE THE OXYGEN SENSOR LIGHT WENT OFF INSTANTLY......WOW!!!!!!


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hardlymoving 4 years ago from Memphis, TN

For me, P0171 was cleared up by replacing the tube connecting the MAP sensor. Car runs better but has a erratic idle. Thinking of replacing all the vacuum tubes and cleaning out the throttle body. Also a fuel filter replacement may be in order.

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