P0154
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
DTC Detection Condition:
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.
HINT: Confirm the heated oxygen sensor (sensor 1) voltage. Enter the given 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.
MONITOR DESCRIPTION
Typical Enabling Conditions:
Typical Malfunction Thresholds:
The ECM uses the heated oxygen sensor to optimize the air-fuel mixture with closed-loop fuel control. This control helps decrease exhaust emissions by providing the catalyst with a nearly stoichiometric mixture. The sensor detects the oxygen level in the exhaust gas and the ECM uses this data to control the air-fuel ratio. The sensor output voltage range is from 0.1 V to 0.9 V. If the signal voltage is less than 0.45 V, the air-fuel ratio is LEAN. If the signal voltage is more than 0.45 V, the air-fuel ratio is RICH. If the sensor does not indicate RICH at least once despite the conditions for the closed-loop fuel control being met and the specified time period has passed, the ECM will conclude that the closed-loop fuel control is malfunctioning. The ECM will illuminate the MIL and a DTC is set.
Wiring Diagram (Part 1):
Wiring Diagram (Part 2):
CONFIRMATION DRIVING PATTERN
1. Connect the intelligent tester to the CAN VIM. Then connect the CAN VIM to the DLC3.
2. Allow the engine to idle until ECT reaches 40 °C (104 °F).
3. Allow the vehicle to run at 60 km/h (38 mph) or more for 3 minutes or more.
Step 1:
Step 1(Continued)-4:
Step 5:
Step 6-9:
Step 9(Continued)-13:
INSPECTION PROCEDURE
HINT: It is possible the malfunctioning area can be found using the ACTIVE TEST A/F CONTROL operation. The ACTIVE TEST can determine if the heated oxygen sensor or other potential trouble areas are malfunctioning or not.
The injection volume can be switched to -12.5% (decrease) or +25% (increase) by the ACTIVE TEST.
The ACTIVE TEST procedure enables a technician to check and graph the output voltage of the heated oxygen sensors.
Procedure:
a. Connect the intelligent tester to the CAN VIM. Then connect the CAN VIM to the DLC3.
b. Turn the engine switch on (IG).
c. Warm up the engine by running the engine at 2,500 rpm for approximately 90 seconds.
d. Enter the given menus: DIAGNOSIS / ENHANCED OBD II / ACTIVE TEST / A/F CONTROL.
e. Perform the ACTIVE TEST while the engine is idling.
Standard: The heated oxygen sensor reacts in accordance with the increase and decrease of injection volume:
+25% RICH output: More than 0.55 V
-12.5% LEAN output: Less than 0.4 V
NOTE: The heated oxygen sensor (sensor 1) output has a few seconds of delay and the heated oxygen sensor (sensor 2) output has a maximum of 20 seconds of delay.
If the vehicle is short on fuel, the air-fuel ratio becomes LEAN and the DTCs will be recorded.
HINT:
- Read freeze frame data using the intelligent tester. Freeze frame data records the engine conditions when a malfunction is detected. When troubleshooting, freeze frame data can help determine if the vehicle was running or stopped, if the engine was warmed up or not, if the air-fuel ratio was LEAN or RICH, and other data from the time the malfunction occurred.
- Bank 1 refers to the bank that includes No. 1 cylinder.
- Bank 2 refers to the bank that does not include No. 1 cylinder.
- No. 1 cylinder is located in the front part of the engine, opposite the transmission.
- Sensor 1 refers to the sensor closest to the engine body.