DTC P0134 Oxygen Sensor Circuit No Activity Detected (Bank 1 Sensor 1); DTC P0154 Oxygen Sensor Circuit No Activity Detected (Bank 2 Sensor 1): Description
The heated oxygen sensor is used to monitor oxygen concentration in the exhaust gas. For optimum catalytic converter operation, the air-fuel mixture must be maintained near the ideal stoichiometric air-fuel ratio. The heated oxygen sensor output voltage changes suddenly in the vicinity of the stoichiometric air-fuel ratio. The ECM adjusts the fuel injection time so that the air-fuel ratio is nearly stoichiometric. The heated oxygen sensor generates a voltage between 0.1 and 0.9 V in response to the oxygen concentration in the exhaust gas.
If the oxygen concentration in the exhaust gas increases, the air-fuel ratio is called LEAN. The heated oxygen sensor voltage drops below 0.45 V, which informs the ECM of the LEAN condition.
If oxygen is not in the exhaust gas, the air-fuel ratio is called RICH. The heated oxygen sensor voltage increases above 0.45 V, which informs the ECM of the RICH condition.
HINT:
The ECM provides a pulse width modulated control circuit to adjust current through the heater. The heated oxygen sensor heater circuit uses a relay on the +B side of the circuit.
| DTC No. | DTC Detection Condition | Trouble Area |
|---|---|---|
| P0134 P0154 |
After engine is warmed up, heated oxygen sensor (sensor 1) does not indicate Rich (greater than 0.45 V) even once when conditions (a), (b) and (c) continue for 20 seconds (2 trip detection logic):
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HINT:
Confirm the heated oxygen sensor (sensor 1) voltage. Enter the following menus: DIAGNOSIS / ENHANCED OBD II / DATA LIST / PRIMARY / O2S B1 S1 (or O2S B1 S2).
If the voltage is less than 0.1 V, the sensor circuit may be open or short.