Oxygen Sensor Heater Circuit Malfunction (Bank 1 Sensor 1)
The engine computer has found a problem in the heater circuit for the upstream oxygen sensor on bank 1. That sensor may not warm up fast enough, so the engine may run poorly until it reaches normal temperature. The issue is usually an electrical problem, a bad sensor heater, or a wiring fault.
You can usually drive short distances, but fuel economy, emissions, and drivability may be affected. Have it checked soon, especially if the engine runs rough, idles badly, or the check engine light is flashing.
P0135 means the PCM detected an open, short, or performance fault in the heater circuit of the upstream oxygen sensor, typically Bank 1 Sensor 1. This heater helps the sensor reach operating temperature quickly so the PCM can control fuel mixture in closed loop. If the heater circuit fails, the sensor response can be delayed and the PCM may store the code and adjust fuel delivery incorrectly.
It means the heater circuit for the upstream oxygen sensor on Bank 1 is not working correctly.
Often yes, but wiring, connectors, fuses, relays, or power and ground problems are also common.
Yes. If the sensor heats slowly or not at all, the engine may stay in open loop longer and use more fuel.
Not always. Check the fuse, wiring, connector, and power supply first because they are common causes and cheaper to fix.