Troubleshooting
DTC P0154 OXYGEN SENSOR CIRCUIT NO ACTIVITY DETECTED (BANK 2 SENSOR 1)CIRCUIT DESCRIPTION
DTC Detection Condition:
The heated oxygen sensor's output voltage changes sharply when the air-fuel ratio is near the ideal stoichio-metric air-fuel ratio. This sensor reaction is useful for detecting the oxygen concentration in the exhaust gas and for providing the ECM with data about what adjustments are necessary for the air-fuel ratio.
If the oxygen concentration in the exhaust gas increases and the heated oxygen sensor voltage is below 0.45 V, the air-fuel ratio is "LEAN". The heated oxygen sensor informs the ECM about the LEAN condition. If the oxygen concentration in the exhaust gas increases and the heated oxygen sensor voltage is about 0.45 V, the air-fuel ratio is "RICH". The heated oxygen sensor informs the ECM about the RICH condition.
HINT: After confirming DTC P0134 and P0154, confirm the output voltage of the heated oxygen sensor with the hand-held tester or the OBD II scan tool. Enter the following menus: DIAGNOSIS / ENHANCED OBD II / DATA LIST / ALL.
MONITOR DESCRIPTION
Monitor Strategy:
Typical Enabling Condition:
Typical Malfunction Thresholds:
Component Operating Range:
The ECM uses the heated oxygen sensor to optimize the air-fuel mixture in 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 ranges from 0 V to 1 V. If the signal voltage is less than 0.4 V, the air-fuel ratio is LEAN. If the signal voltage is more than 0.55 V, the air-fuel ratio is RICH. If the conditions for the closed-loop fuel control are met and after a specified time-period, the sensor's output signal never indicates RICH, 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:
CONFIRMATION DRIVING PATTERN
Confirmation Driving Pattern:
a. Connect the hand-held tester to the DLC3.
b. Switch the hand-held tester from "normal mode" to "check mode".
c. Start the engine and let the engine idle for 120 seconds or more.
d. Drive the vehicle at 25 mph (40 km/h) or more for 40 seconds or more.
e. Let the engine idle for 20 seconds or more. Perform steps (d) and (e) at least 3 times.
f. Let the engine idle for 30 seconds.
HINT: If a malfunction exists, the MIL will be illuminated on the multi information display during step (f).
NOTE: If the conditions in this test are not strictly followed, detection of a malfunction will not occur. If you do not have the hand-held tester, turn the ignition switch OFF after performing steps from (c) to (f), and then perform steps from (c) to (f) again.
INSPECTION PROCEDURE
HINT:
Hand-held tester only:
Narrowing down the trouble area is possible by performing "A/F CONTROL" ACTIVE TEST (heated oxygen sensor or other trouble areas can be distinguished).
Perform the ACTIVE TEST's A/F CONTROL operation.
HINT: "A/F CONTROL" is the ACTIVE TEST which changes the injection volume to -12.5 % or +25 %.
1. Connect the hand-held tester to the DLC3 on the vehicle.
2. Turn the ignition switch ON.
3. Warm up the engine by running the engine speed at 2,500 rpm for approximately 90 seconds.
4. Select the item "DIAGNOSIS / ENHANCED OBD II / ACTIVE TEST / A/F CONTROL".
5. Perform "A/F CONTROL" with the engine in an idle condition (press the right or left button).
RESULT:
Heated oxygen sensor reacts in accordance with increase and decrease of injection volume
+25 % -> rich output: More than 0.55 V
-12.5 % -> lean output: Less than 0.4 V
NOTE: There is a delay of few seconds in the sensor 1 (front sensor) output, and there is about 20 seconds delay at maximum in the sensor 2 (rear sensor).
The following of A/F CONTROL procedure enables the technician to check and graph the voltage outputs of both the heated oxygen sensors.
To display the graph, enter the following menus: ACTIVE TEST / A/F CONTROL / USER DATA. Then select O2S B1S1 and O2S B1S2 by pressing YES. Finally, push ENTER and F4.
Step 1 - 2:
Step 3 - 5:
Step 6 - 8:
Step 9 - 12:
Step 13 - 14:
HINT:
- Read freeze frame data using the hand-held tester or the OBD II scan tool. 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.
- A high heated oxygen sensor (sensor 1) voltage (0.5 V or more) could be caused by a rich air fuel mixture. Check for conditions that would cause the engine to have a rich air-fuel mixture.
- A low heated oxygen sensor (sensor 1) voltage (0.4 V or less) could be caused by a lean air fuel mixture. Check for conditions that would cause the engine to have a lean air-fuel mixture.
CHECK FOR INTERMITTENT PROBLEMS
Hand-held tester only:
Inspect the vehicle's ECM using check mode. Intermittent problems are easier to detect when the ECM is in check mode. In check mode, the ECM uses 1 trip detection logic, which has a higher sensitivity to malfunctions than normal mode (default), which uses 2 trip detection logic.
a. Clear the DTCs.
b. Change to check mode.
c. Perform a simulation test.
d. Check the connector and terminal.
e. Wiggle the harness and connector.