P0154

P0154 HO2S1







Component Description
The heated oxygen sensor 1 (front) is placed into the front tube. It detects the amount of oxygen in the exhaust gas compared to the outside air. The heated oxygen sensor 1 (front) has a closed-end tube made of ceramic zirconia. The zirconia generates voltage from approximately 1 V in richer conditions to 0 V in leaner conditions. The heated oxygen sensor 1 (front) signal is sent to the ECM. 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 1 V to 0 V.

Consult-II Reference Value In Data Monitor Mode:

ECM Terminals And Reference Value:

On Board Diagnosis Logic
Under the condition in which the heated oxygen sensor 1 (front) signal is not input, the ECM circuits will read a continuous approximately 0.3 V. Therefore, for this diagnosis, the time that output voltage is within 200 to 400 mV range is monitored, and the diagnosis checks that this time is not inordinately long. Malfunction is detected when the voltage from the sensor is constantly approx. 0.3 V.

POSSIBLE CAUSE
- Harness or connectors
(The sensor circuit is open or shorted.)

- Heated oxygen sensor 1 (front)

DTC Confirmation Procedure

CAUTION: Always drive vehicle at a safe speed.

NOTE: If "DTC Confirmation Procedure" has been previously conducted, always turn ignition switch OFF and wait at least 5 seconds before conducting the next test.

TESTING CONDITION: Before performing the following procedure, confirm that battery voltage is more than 11 V at idle.

With CONSULT-II
1. Start engine and warm it up to normal operating temperature.
2. Select "HO2S1 (B1)/(B2) P0134/P0154" of "HO2S1" in "DTC WORK SUPPORT" mode with CONSULT-II.
3. Touch "START".
4. Let it idle for at least 3.5 minutes.

NOTE: Never raise engine speed above 2,800 rpm after this step. If the engine speed limit is exceeded, return to step 4.

5. When the following conditions are met, "TESTING" will be displayed on the CONSULT-II screen. Maintain the conditions continuously until "TESTING" changes to "COMPLETED". (It will take approximately 10 to 60 seconds.)

If "TESTING" is not displayed after 5 minutes, retry from step 2.

6. Make sure that "OK" is displayed after touching "SELF-DIAG RESULTS". If "NG" is displayed, refer to "Diagnostic Procedure" below.

During this test, P1148 and P1168 may be stored in ECM.

Overall Function Check
Use this procedure to check the overall function of the heated oxygen sensor 1 (front) circuit. During this check, a 1st trip DTC might not be confirmed.

Without CONSULT-II
1. Start engine and warm it up to normal operating temperature.




2. Set voltmeter probes between ECM terminal 50 (bank 1 signal) or 51 (bank 2 signal) and engine ground.
3. Check the following with engine speed held at 2,000 rpm constant under no load.
- The voltage does not remain in the range of 0.2 - 0.4 V.

4. If NG, go to "Diagnostic Procedure" below.

EC-O2S1B1-01:

EC-O2S1B2-01:

Wiring Diagram


Diagnostic Procedure

Step 1:

Step 2:

Step 3:

Step 4 - 5:

Step 6 - 7: