Lexus: What Does Error Code P0135 Mean?
P0135 is the OBD-II generic code indicating that the PCM has detected a problem with the bank 1 oxygen sensor 1.
This article applies to the Lexus IS, RX, GS, LS, and ES (2005-Present).
Every Lexus vehicle comes equipped with an OBD connector which can be used to send messages to an OBD2 troubleshooting reader like the one below. Simply connect the scanning tool (or a computer with scanning software downloaded) to the connector (located under the steering wheel) and the readout will show you Diagnostic Trouble Codes that might be affecting your car. From there, you can look up the code at ClubLexus.com to learn what's going on and try to repair it yourself. If you are not comfortable diagnosing and repairing your car, please take it to a Lexus service center. Scanner programs and tools vary in price. An app can be purchased for $4.95, and an OBD-II Scanner/Code Reader can be purchased for anywhere between $19 and $300+ depending on what service functions you need.
P0135 Definition
P0155 is the OBD-II generic code indicating that the PCM has detected a circuit malfunction with the bank 2 oxygen sensor 1.
P0135 Explained
The O2 Sensor unit is located just in front of the catalytic converter and its job is to examine the concentration of oxygen in the exhaust gas coming out of the engine. The PCM (powertrain control module) uses this information to adjust the amount of air that mixed into the fuel (air/fuel ratio) going into the motor. Nowadays, most cars are equipped with heated O2 sensors (HO2S) which also contain a heater to bring the unit to operating temperature, which in turn, allows the PCM to receive the correct data soon after the car is turned on. When the PCM detects an issue with the heated O2 Sensor, the check engine light will turn on.
P0135 refers to such an issue specifically in sensor 1 of bank 1, which is on the side of the engine that has the #1 cylinder. Bank 2 is the opposite side of the engine. If you have a four-cylinder, there will only be one bank, and you would not get this code.
P0135 Symptoms
- Poor fuel economy (not noticeable)
- Failed emissions test
The only symptom that is actually noticeable is the check engine light coming on.