99 Avalon check engine codes 1133/1135

Hi, I'm new to the engine codes thing. was told today by an auto store that it is a air-fuel ratio message. I've seen other posts on these codes but am still confused, is it an air-fuel sensor or an O2 sensor or are they the same? Is there a sensor in the front and rear exhaust? Are these codes for the rear exhaust bank? Seems that we can check the continuity and resistance on them. Any other help would be appreciated. It all started when I filled up so I thought it was the gas cap...thanks

Hi, I'm new to the engine codes thing. was told today by an auto store that it is a air-fuel ratio message. I've seen other posts on these codes but am still confused, is it an air-fuel sensor or an O2 sensor or are they the same? Is there a sensor in the front and rear exhaust? Are these codes for the rear exhaust bank? Seems that we can check the continuity and resistance on them. Any other help would be appreciated. It all started when I filled up so I thought it was the gas cap...thanks

P1133 Air-Fuel Sensor Circuit Response Malfunction Bank 1 Sensor 1 (Only for California Spec)
P1135 Air-Fuel Sensor Heater Circuit Malfunction Bank 1 Sensor 1 (California Spec.)

The A/F ratio sensors and HO2 (Heated Oxygen) sensors do the same thing in different ways. There are two sensors before the cat converter (Bank 1 Sensor 1 and Bank 2 Sensor 1) and there is one behind the cat converter (Bank 1 Sensor 2). Bank 1 Sensor 1 is the sensor behind your engine on the rear cylinder bank (rear). The other Sensor 1 in front of the engine is on Bank 2.

Since you apparently have a California car, you have A/F Ratio sensors at Sensor 1. Sensor 2 is an HO2 sensor, but it is apparently not the malfunctioning sensor.

Possible problems:
Open or short in the A/F ratio sensor circuit
Open or short in A/F ratio sensor heater circuit
Bad Sensor/sensor heater
Problem with the air induction system
Low fuel pressure
Injector(s) not functioning - plugged, not connected, bad wiring

If you end up replacing the sensor, bring your VIN to a dealer to make sure you get the correct sensor. You don't have to buy one there, but get the correct part number for reference.

FYI, DTC 1133 can be triggered by running out of gas. Try pulling the ECM fuse, replacing it, and then see if the codes reappear. These codes have 2 trip detection logic, so you will have to drive the car twice before they will come back if they are going to come back.

If I was a betting man, I'd bet you need a new Bank 1 Sensor 1.

thanks Brian for the helpful info. I'll check it out tomorrow.

Anyone know how to get a free Carfax? thanks

Sorry, can't solicit that kind of information from here.

I tried pulling the ECM fuse ( with the car off) but that did not reset the warning light. Is there something I'm missing here?

I haven't checked the sensor yet - my short arms don't help here. My engine runs fine; is there a problem with it running in this condition? thanks again.

http://inlinethumb15.webshots.com/4942/2695479270043892667S600x600Q85.jpg
Check the A/F sensor HEATER relay marked A/F HTR in the fuse box by the battery. It's +B: black/white wire’ HT: light green wire’ O2S signal wire: black.
There was a modified update for the B1S1 sensor in your 1999, but it's too late now for a freebee.
You can check the B1S1 sensor http://www.clublexus.com/forums/attachment.php?attachmentid=88086&stc=1
After 10 years I'd go ahead and replace it with a Denso orginal for less than $200 if you do the work. Good Luck!

CSaxon - I have the same issue with my 99. Except I also got P1130 and it is not a CA car. Is it safe to assume I need to look at the same fix you suggested above?? Thanks!

It must be fate tjancse. I just happened to check out this forum. I'm rarely here anymore. But the answer is yes. The 1130 is this sensor. I prefer the Denso "First time fit" sensors. They're easy to replace.
http://inlinethumb32.webshots.com/4895/2787719730043892667S600x600Q85.jpg