Replacing air / fuel sensor on the 2005 Civic EX (error code: P0134)

i would check ur fuses that supply voltage to ur o2 sensors, their in the fuse box and usually r labeled o2 sensr. sounds like the o2 sensrs dont have power

with those codes showing, it could be either bad O2 sensors or there is a problem with the wiring to those sensors. Also, the wrong sensors may be installed. I'm assuming codes P0134, P0135, P0155.

For others viewing this:

P0134 = O2 sensor circuit-no activity detected (bank 1 sensor 1)

P0135 = O2 sensor heater circuit malfunction (bank 1 sensor 1)

P0155 = O2 sensor heater circuit malfunction (bank 2 sensor 1)

Dont mean to be a prude but that diagnosis is incorrect. A fouled spark plug, vacuum leak, ect.. will not trigger this diagnostic code alone. If in fact you had a fouled plug or vacuum leak the P0134 code would be followed with another diagnostics code. If the P0134 code is the only code pulled then this code is triggered by the voltage of the o2 sensor being 3V or higher. The front heated oxygen sensor (or sensor 1) is placed into the exhaust manifold. It detects the amount of oxygen in the exhaust gas compared to the outside air. The heated oxygen sensor 1 has a closed-end tube made of ceramic zirconia. The zirconia generates voltage from approximately 1V in richer conditions to 0V in leaner conditions. The heated oxygen sensor 1 signal is sent to the The ECM adjusts the injection pulse duration to achieve the ideal air-fuel ratio. The ideal air-fuel ratio occurs near the radical change from 1V to 0V.

The causes for this code:
- Harness or connectors (The sensor circuit is open or shorted)
- Front Heated oxygen sensor (Bank 1) may be faulty

To correct this code:
- Replacing the O2 Sensor 1 usually takes care of the problem.
- Replace the damaged harness or connectors.

This code refers to the front oxygen sensor on Bank 1. Basically the oxygen sensor is inactive.

DTC P0134 - 02 Sensor Circuit No Activity Detected (Bank I Sensor 1)

The powertrain control module (PCM) provides a baseline voltage of about 450 mV on the oxygen sensor signal circuit. When cold, the PCM detects the the internal resistance of the sensor is high. As the sensor warms up the resistance is lowered and it starts producing voltage based on the oxygen content in the exhaust. When the PCM determines that the time it took for the sensor to warm up is greater than one minute or that the voltage is inactive (not reading outside 391-491 mV it views the sensor as inactive or open and sets the P0134 code.

Potential Symptoms: One or more of the following may occur:
* Check engine light illumination
* Poorly running/engine missing
* Blowing black smoke
* Poor fuel economy
* Dying, stuttering

Causes: A code P0134 may mean that one or more of the following has happened:
* Bad O2 (oxygen) sensor
* Bad heater circuit in the O2 sensor
* Wiring or connector to the sensor frayed / broken
* Blown heater circuit fuse
* Holes in the exhaust system
* PCM failure

Possible Solutions: The most common fix is to replace the oxygen sensor. But that doesn't rule out the possibility of:
* Rusted exhaust pipe
* Inspect wiring & connector(s) for problems
* Excessive amperage blowing heater fuse (still requires replacement of sensor but also replacement of blown fuse)
* Replace PCM (only as last resort after all other possibilities are covered.


Hope helps (remember rated and comment this).

The code refers to an oxygen sensor that is no longer detecting changes in fuel delivery by way of sensing exhaust oxygen content. Bank 1, sensor 1, tells you which sensor is bad, in this case, it's the sensor that is mounted before the catalytic converter, on the rear bank of cylinders as you look into the engine compartment. It would really be a good idea to change both pre-cat O2 sensors at this point as they are both twelve years old.