'99 Avalon with check engine light

[Supranaut]

My wife's Avalon has just over 100k and yesterday morning the check engine light came on. Codes are:
P00125 -insufficient coolant temp for closed loop control
P01133 -A/F sensor circuit response(bank1 sensor1)
P01135 -A/F sensor heater curcuit malfunction(bank1 sensor1)

Any ideas would be much appreciated! Sounds like a bad O2 sensor?

[RIP]

Air/fuel sensors have been used in place of oxygen sensors for several years now. Yes, could be an air fuel sensor.

It appears all these could be related. I would reset the codes and see which come back. Pull the EFI fuse for a minute and reinsert or disconnect the battery. The later will dump radio presets and the clock.

Just a hunch but I'm thinking if you fix the P0125 code you might fix it all: http://www.obd-codes.com/trouble_cod...el-control.php Check the coolant level.

[Supranaut]

I did a reset and ended up with the same codes...I'll check the temp sensor tonight. Thanks!

[papirringo]

I would replace the af sensor, the P0125 code is going to be set if the car is running lean, so this code is because of the af sensor that is not working prop.

[Supranaut]

Originally Posted by papirringo

I would replace the af sensor, the P0125 code is going to be set if the car is running lean, so this code is because of the af sensor that is not working prop.

Ordered the sensor today...we'll see if that cures all!

[Supranaut]

Replacing the A/F sensor cured all...Thanks for the help everyone!

[RIP]

Hey, thank you for posting the fix.