P1144
DTC P1144 HO2S1
Component Description
The heated oxygen sensor 1 is placed into the exhaust manifold. It detects the amount of oxygen in the exhaust gas compared to the outside air. The heated oxygen sensor 1 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 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
On Board Diagnosis Logic
To judge the malfunction, the output from the heated oxygen sensor 1 is monitored to determine whether the rich output is sufficiently high and lean output is sufficiently low. When both the outputs are shifting to the rich side, the malfunction will be detected.
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 10 seconds before conducting the next test.
TESTING CONDITION:
- Always perform at a temperature above -10 °C (14 °F).
- 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. Stop engine and wait at least 5 seconds.
3. Turn ignition switch ON and select "HO2S1 (B1) P1144" of "HO2S1" in "DTC WORK SUPPORT" mode with CONSULT-II.
4. Touch "START".
5. Start engine and let it idle for at least 3 minutes.
NOTE: Never raise engine speed above 3,600 rpm after this step. If the engine speed limit is exceeded, return to step 5.
6. When the given 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 50 seconds or more.)
If "TESTING" is not displayed after 5 minutes, retry from step 2.
7. Make sure that "OK" is displayed after touching "SELF-DIAG RESULTS". If "NG" is displayed, refer to "Diagnostic Procedure" below.
Overall Function Check
Use this procedure to check the overall function of the heated oxygen sensor 1 circuit. During this check, a 1st trip DTC might not be confirmed.
WITH GST
1. Start engine and warm it up to normal operating temperature.
2. Set voltmeter probes between ECM terminal 35 [HO2S1(B1) signal] and ground.
3. Check one of the following with engine speed held at 2,000 rpm constant under no load.
- The maximum voltage is below 0.8 V at least 1 time.
- The minimum voltage is below 0.35 V at least 1 time.
4. If NG, go to "Diagnostic Procedure" below.
Diagnostic Procedure (Steps 1 - 2):
Diagnostic Procedure (Steps 3 - 5):
Diagnostic Procedure (Steps 6 - 7):
Diagnostic Procedure
Component Inspection
HEATED OXYGEN SENSOR 1
With CONSULT-II
1. Start engine and warm it up to normal operating temperature.
2. Select "MANU TRIG" and adjust "TRIGGER POINT" to 100% in "DATA MONITOR" mode with CONSULT-II.
3. Select "HO2S1 (B1)" and "HO2S1 MNTR (B1)".
4. Hold engine speed at 2,000 rpm under no load during the following steps.
5. Touch "RECORD" on CONSULT-II screen.
6. Check the following.
- "HO2S1 MNTR (B1)" in "DATA MONITOR" mode changes from "RICH" to "LEAN" to "RICH" more than 5 times in 10 seconds.
5 times (cycles) are counted as shown at right.
- "HO2S1 (B1)" voltage goes above 0.6 V at least once.
- "HO2S1 (B1)" voltage goes below 0.3 V at least once.
- "HO2S1 (B1)" voltage never exceeds 1.0 V.
CAUTION:
- Discard any heated oxygen sensor which has been dropped from a height of more than 0.5 m (19.7 in) onto a hard surface such as a concrete floor; use a new one.
- Before installing new oxygen sensor, clean exhaust system threads using Oxygen Sensor Thread Cleaner tool J-43897-18 or J-43897-12 and approved anti-seize lubricant.
Without CONSULT-II
1. Start engine and warm it up to normal operating temperature.
2. Set voltmeter probes between ECM terminal 35 [HO2S1 (B1) signal] and ground.
3. Check the following with engine speed held at 2,000 rpm constant under no load.
- The voltage fluctuates between 0 to 0.3 V and 0.6 to 1.0 V more than 5 times within 10 seconds.
- The maximum voltage is over 0.6 V at least 1 time.
- The minimum voltage is below 0.3 V at least 1 time.
- The voltage never exceeds 1.0 V.
1 time: 0 - 0.3 V -> 0.6 - 1.0 V -> 0 - 0. 3 V
2 times: 0 - 0.3 V -> 0.6 - 1.0 V -> 0 - 0.3 V -> 0.6 - 1.0 V -> 0 - 0.3 V
CAUTION:
- Discard any heated oxygen sensor which has been dropped from a height of more than 0.5 m (19.7 in) onto a hard surface such as a concrete floor; use a new one.
- Before installing new oxygen sensor, clean exhaust system threads using Oxygen Sensor Thread Cleaner tool J-43897-18 or J-43897-12 and approved anti-seize lubricant.