'99 Avalon with both the MIL and Trac Off light On

edge

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I have a '99 Avalon with both the MIL and Trac Off light on. The MIL came on first with codes P0125 and P1133 pending. After some research I believe this was caused by a bad A/F sensor on B1/S1. I have not replaced the sensor yet. I checked the codes a second time before the Trac Off light ON and the additional codes were P1133, P1135, P1135 Pending. After about 200 - 300 miles the Trac Off light came on. I was not driving the car at the time, but from what I can tell it happened during/after a two times spinning the tires from a stop in the rain. I just scanned for codes and found no additional codes compared to the second scan above.
 

2POINTautO

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#2
Its very good that you collected the codes, go ahead and clear them and see what comes back and see if both of the lights come on at the same time next time, sometimes these light are tied together depending on what code is set from what system.

Make sure if this is actually Sensor 1 or Sensor 2 for the P1133, also either contact the dealer or check on the internet for a TSB that may apply to your Toyota mentioning an updated part number for the O2 sensor.
 

edge

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I reset the MIL and it came on without the Trac Off light. I scanned for codes again and P0125, P1135 and P1135 pending, but no P1133. Any idea why I am not getting the P1133 now? P1135 is for Air/Fuel Sensor Heater Circuit Response for B1/S1. I did check the voltage on heater circuit before I checked the codes the second time, which was 9. 5 v. I did not check the resistance of the sensor heater, but plan to do this. According to TSB EG002-00 Revised for the Camry with the same engine, P1133 is for a defective B1/S1. There is no TSB for the Avalon that I can find. Denso the mfg of the sensor, confirms P1133 is B1/S1.
 

2POINTautO

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#4
You may need to complete two drive cycles and the monitor may need to complete, I dont know the criteria for the code to set but some driving is probably needed, the computer is going to check for crosscounts (O2 activity) before setting a code.
 

csaxon

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#5
The AF sensor for your car year was replaced with an updated sensor because of the codes you mention. 1133 is for a Cal spec car. Replace B1S1.
 

edge

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#6
Problem Fixed - The MIL is off . Replaced B1/S1 AF sensor with a new sensor. There was an open circuit in heater circuit of the old sensor. Just as a point of info, I had read that when the A/F sensor malfunctions the PCM may reduce power and load to the engine which may shut-off the Traction Control. Thanks guys.