rmk9785e

My 1990 RX300 has the Check Engine Light on. I had previously posted this issue but am unable to locate my previous posting and its responses through the forum Search.

I was advised at that time to get an analyzer, reset the CEL and see if they come back. I am using AutoTap Express DIY and the codes keep returning so it is confirmed that these three codes need to be addressed.

The Oxygen Sensor Monitor and Evaporative Sensor Monitor tests don't complete with AutoTap. The Oxygen Sensor Heater Monitor and catalyst Monitor tested successfully.

Based upon the above information, which sensors do I need to change and what are the best OEM part numbers for them?

Thank you.

Lexmex

If these codes have been coming back and again, then focus on the P1130 and P1135, you need a new a/f (air fuel sensor). Amazon has the Denso 234-9009 sensors for usually the lowest price around. Both codes relate to the bank 1, sensor 1 sensor behind the engine block. See this DIY by 81corolla, https://www.clublexus.com/forums/rx-...el-sensor.html that location is shown in the first few photos.

rmk9785e

Thank you for the links to detailed info. How do I figure out which of the three sensors needs replacing? The Autotap Express DIY program is loaded on my laptop so I can get all the readings but don't know which one indicates a specific bad sensor.

rmk9785e

Wonder if this data gives any indication of which sensor is defective.

Engine RPM: 811
Intake air temperature: 136.4F

Bank 1 Sensor 1 Oxygen Sensor voltage: 0.66V
Bank 1 Sensor 1 Short Term Fuel Trim: -2.34375%
Bank 1 Sensor 2 Oxygen Sensor Voltage: 0.85V
Bank 2 Sensor 1 Short Term Fuel Trim: -3.125%%
Bank 2 Sensor 1 Oxygen Sensor Voltage: 0.66V

Thank you.

bearbrew

The codes you posted, P1130 & P1135, indicates the Bank 1, Sensor 1 Air/Fuel Sensor located in the exhaust manifold on the aft side of the engine as Lexmex stated in post #2 above.

Neither of the sensors on my RX300 were seized in place so I was able to remove them with an open end wrench and a dead blow hammer. If they are seized you may need the sensor socket for removal.

Use a good penetrant, not WD40, the day before and again before you remove the sensor. The electrical connector can be quite tight and a PITA but once you get the latch over-centered it will come apart.

Bear

rmk9785e

Thank you both. It helps to read the directions.