Trouble Code: P0136

[Brooki110]

Hi Everybody,

I am owner of a 2003 Lexus RX300 with 69000 miles and recently got an"Engine Check Light & VSC" came on. I went to "Advance Auto Parts" store and without absolutely no charge scanned the trouble code, which is P0136 - O2 Sensor Circuit Malfunction (Bank 1 Sensor 2).

I decided to figure out myself how to fix this kind of problem. I did a lot of googling, but I couldn't find any good pointed answer for this particular vehicle.

However, this is the only website where I found 100% information about RX300. By checking very carefuly "2003 RX300 Repair manual" 2003 RX300 Repair manual

I have found some steps to check the sensor:

1. Remove the driver's seat

2. Take out the floor carpet

3. Disconnect the oxygen sensor connector

4. Using an ohmmeter, measure the resistance between the terminals +B and HT

Resistance: 11-16 ohm

If the resistance is not as spacified, replace the sensor.

I'd checked the sensor and it is 15 ohm, so it means that the sensor is working propertly.

I also found some general information about 02 sensor:

"A code P0136 may mean that one or more of the following has happened:

Faulty O2 sensor leak in exhaust close to O2 sensor

Short to voltage on O2 signal circuit

Open in circuit resistance caused by corrosion in connector "

Please help me figure out what the problem is and if I need to replace this sensor even though it is working?

Thanks!

[smyrnagc]

Had the same problem with our 2002 RX 300 and it turned out to be a bad gas cap and the line/tube that connects to the bottom of the air filter box had come loose during an oil change at Valvoline. Reconnected the line and bought a new gas cap for $7 and the problem was fixed. Might not be your problem but you can find many threads on this site that deal with check engine light and VSC. 95% of the time it indicates bad O2 sensors but the majority of the time that is not the case.

Do a search under "CEL and VSC" for you model here and on Google.

Good luck...

[Brooki110]

Had the same problem with our 2002 RX 300 and it turned out to be a bad gas cap and the line/tube that connects to the bottom of the air filter box had come loose during an oil change at Valvoline. Reconnected the line and bought a new gas cap for $7 and the problem was fixed. Might not be your problem but you can find many threads on this site that deal with check engine light and VSC. 95% of the time it indicates bad O2 sensors but the majority of the time that is not the case.

Do a search under "CEL and VSC" for you model here and on Google.

Good luck...

Thanks for your reply. I checked all recommended and was not able to fix my problem. I even purchsed a gas cap, but after 20 minutes of driving, the "CEL" came back on. I will probably have to go to the dealer. Your help is greatly appreciated.