Troubleshooting
DTC P0154 Oxygen Sensor Circuit No Activity Detected (Bank 2 Sensor 1)CIRCUIT DESCRIPTION
DTC Detecting Condition:
To obtain a high purification rate for the CO, HC and NOx components of the exhaust gas, a three-way catalytic converter is used, but for the most efficient use of the three-way catalytic converter, the air-fuel ratio must be precisely controlled so that it is always close to the stoichiometric air-fuel ratio.
The A/F sensor has the characteristic that provides output voltage* approximately proportional to the existing air-fuel ratio. The A/F sensor output voltage* is used to provide feedback for the ECM to control the air-fuel ratio.
By the A/F sensor output, the ECM can determine the deviation amount from the stoichiometric air-fuel ratio and control the proper injection time immediately. If the A/F sensor is malfunctioning, ECM is unable to perform accurate air-fuel ratio control.
The A/F sensor is equipped with a heater which heats the zirconia element. The heater is controlled by the ECM. When the intake air volume is low (the temp. of the exhaust gas is low), current flows to the heater to heat the sensor for accurate oxygen concentration detection.
*: The voltage value changes at the inside of the ECM only.
HINT:
- After confirming DTCs P0134 or P0154, use the OBD II scan tool or hand-held tester to confirm voltage output of the A/F sensor (bank 1, 2 sensor 1) from the CURRENT DATA.
- The ECM controls the voltage of the AFR+, AFL+, AFR - and AFL- terminals of the ECM to the fixed voltage. Therefore, it is impossible to confirm the A/F sensor output voltage without the OBD II scan tool or hand-held tester.
- OBD II scan tool (excluding hand-held tester) displays the one fifth of the A/F sensor output voltage which is displayed on the hand-held tester.
MONITOR DESCRIPTION
Monitor Strategy:
Typical Enabling Conditions:
Typical Malfunction Thresholds:
The Engine Control Module (ECM) uses Air Fuel (A/F) sensor(s) to optimize the air/fuel mixture in Closed Loop fuel control.
This control helps decrease exhaust emissions by providing the catalyst with e nearly stoichiometric mixture.
The ECM calculates the air fuel ratio in the exhaust stream from the sensors output signal. When conditions for Closed Loop fuel control are met and the sensor's response becomes very slow (calculated as the sensor's "locus" length), the ECM interprets this as a malfunction in the Closed Loop fuel control. The ECM illuminates MIL and sets a DTC.
Wiring Diagram:
CONFIRMATION DRIVING PATTERN
Confirmation Driving Pattern:
1. Connect the hand-held tester to the DLC3.
2. Switch the hand-held tester from normal mode to check mode .
3. Start the engine and warm it up for 2 min. or more with all accessory switches OFF.
4. Drive the vehicle at 60 - 120 km/h (38 - 75 mph) and engine speed at 1,600 - 3,200 rpm for 3 - 5 minutes
HINT: If a malfunction exists, the MIL will light up during step (4).
NOTE: If the conditions in this test are not strictly followed, detection of the malfunction will impossible. If you do not have a hand-held tester, turn the ignition switch OFF after performing steps(3) and (4), then perform steps (3) and (4) again.
Step 1:
Step 2 - 3:
Step 3 (Continued):
Step 4 - 7:
Step 8 - 12:
Step 13 - 17:
Step 18 - 19:
INSPECTION PROCEDURE
HINT:
- If DTC P0134 is displayed, check Bank 1 Sensor 1 circuit.
- If DTC P0154 is displayed, check Bank 2 Sensor 1 circuit.
- If the vehicle runs out of fuel, the air-fuel ratio is LEAN and DTCs P0134 and/or P0154 are recorded. The MIL then comes on.
- Read freeze frame data using OBD II scan tool or hand-held tester, as freeze frame data records the engine conditions when a malfunction is detected. When troubleshooting, it is useful for determining whether the vehicle was running or stopped, the engine was warmed up or not, the air-fuel ratio was lean or rich, etc. at the time of the malfunction.
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 with hand-held tester. 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. Set the check mode.
c. Perform a simulation test.
d. Check the connector and terminal.
e. Wiggle the harness and connector.