2000 Avalon Check Engine Light

huyviet · #1 (**permalink**) 08-05-2006, 11:15 AM

Hi,

I have 2000 Avalon with 56K miles which recently used more fuel than normal and check engine light problem. I took it to the Autozone and diagnosed it and they gave me a code of P1155 (alternate fuel controller). However, they don't know what that means. I read other engine light forum threads and can't find an answer. Could someone help me on this?

Thanks.

garagedude · #2 (**permalink**) 08-31-2006, 05:42 PM

The error code P1155 and P1135 and resulting check engine light is due to failure of one or more A/F Sensors (Air/Fuel sensor, or sometimes called Oxygen Sensor). There are three in my 2002 Avalon. There are two parts to the sensor - a heater that heats up the sensor quickly, and the Oxygen sensing part. The error code says you have a problem with the heater. Your mileage after warm up should be normal if O2 part is working OK. If you get consistent bad mileage, I would get it fixed ASAP as an over rich mixture will shorten the life of the CAT converter.
SENSOR TYPES (at least on my 2002 verify for you 200 avalon)
Bank2 Sensor 1 - front of engine exhaust manifold
Toyota part 89467-41040 by DENSO. OEM equiv. Denso 234-9021
Heater resistance check at 68 degrees F 0.8 to 1.4 ohms
Bank 1 Sensor 1 - rear engine exhaust manifold
Toyota part 89467-41030 by DENSO. OEM Equiv. DENSO 234-9021
Cost of these about $180 each - find via google search. Toyota price
about $230 each.
Heater resistance check - same as above
Bank 1 Sensor 2 - under car in back of Catl. Converter, Connecter under
passenger front seat.
Toyota part 89465-07040 by DENSO. OEM Equiv. DENSO 234-4061
OEM part costs about $83.
heater resistance check at 68 degrees F. 11 - 16 ohms.
You need to unplug each sensor, and test resistance reading between the two terminals in sensor plug that have the two black wires into plug. This will check if the heater in the sensor is open or shorted. Resistance readings are as shown above. You will probably find one or more that have failed. I had two out of three bad!!!!
The front sensor - easy to get to and remove. The rear one - you can fish your hands down from the top to unscrew and disconnect. The one by the cat. Converter - remove four bolts holding passenger seat, lean it back out of your way. Pull carpet out from under the plastic on the center console, pull out as best you can, you will see the sensor connector and the wires coming through the floor board. Disconnect the connector, and push the rubber grommet out the hole - then you should be able to unscrew the sensor.
You are on your own using OEM. I did but only have one day on them. This procedure is a guide only - you are on your own. One needs to be fairly mechanical to pull this off... Good luck. Hope this helps……