P0151
COMPONENT DESCRIPTION
The heated oxygen sensor 1 (front) 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 (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.
CAUTION: Do not use ECM ground terminals when measuring voltage. Doing so may result in damage to the ECM's transistor. Use a ground other than ECM terminals such as the body ground.
Consult-II Reference Value In Data Monitor Mode:
ECM Terminals Reference Value:
ON BOARD DIAGNOSIS LOGIC
To judge the malfunction, the output from the heated oxygen sensor 1 (front) is monitored to determine whether the "rich" output is sufficiently high and whether the "lean" output is sufficiently low. When both the outputs are shifting to the lean side, the malfunction will be detected.
DIAGNOSTIC TROUBLE CODE CONFIRMATION PROCEDURE
CAUTION: Always drive vehicle at a safe speed.
NOTE: If "DIAGNOSTIC TROUBLE CODE CONFIRMATION PROCEDURE" has been previously conducted, always turn ignition switch "OFF" and wait at least 5 seconds before conducting the next test.
TESTING CONDITION:
- Always perform at a temperature above -10 °C (14 °F).
- Before performing following procedure, confirm that battery voltage is more than 11 V at idle.
With Consult
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) P0131, (B2) P0151" of "HO2S1" in "DTC WORK SUPPORT" mode with CONSULT-II.
4. Touch "START".
5. Start engine (TCS switch "OFF") and let it idle for at least 3 minutes.
NOTE: Never raise engine speed above 3,200 rpm after this step. If the engine speed limit is exceeded, return to step 5.
6. 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 50 seconds.)
CMPS-RPM (POS): 1,200 - 2,200 rpm
Vehicle speed: 0 - 100 km/h (0 - 62 MPH)
B/FUEL SCHDL: 1.4 - 5.0 ms
Selector lever: Suitable position
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".
OR
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
1. Start engine and warm it up to normal operating temperature.
2. Set voltmeter probes between ECM terminal (83) (B2), (82) (B1) (sensor signal) and ground.
3. Check the following with engine speed held at 2,000 rpm constant under no load.
- The maximum voltage is over 0.6 V at least one time.
- The minimum voltage is below 0.1 V at least one time.
4. If NG, go to "DIAGNOSTIC PROCEDURE".
DIAGNOSTIC PROCEDURES
COMPONENT INSPECTION
Heated oxygen sensor 1 heater (front)
Check resistance between terminals (3) and (1).
Resistance: 2.3 - 4.3 ohm at 25 °C (77 °F)
Check continuity between terminals (2) and (1), (3) and (2). Continuity should not exist.
If NG, replace the heated oxygen sensor 1 (front).
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.
Heated oxygen sensor 1 (front)
With Consult
1. Start engine and warm it up to normal operating temperature.
2. Select "MANU TRIG" and "HI SPEED" in "DATA MONITOR" mode with CONSULT-II, and select "HO2S1 (B1) (B2)" and "HO2S1 MNTR (B1) (B2)".
3. Hold engine speed at 2,000 rpm under no load during the following steps.
4. Touch "RECORD" on CONSULT-II screen.
5. Check the following.
- "HO2S1 MNTR (B1) (B2)" in "DATA MONITOR" mode changes from "RICH" to "LEAN" to "RICH" 5 times in 10 seconds.
5 times (cycles) are counted as shown below:
cycle | 1 | 2 | 3 | 4 | 5 |
HO251 MNTR (B1) R-L-R-L-R-L-R-L-R-L-R
R = "HO2S1 MNTR (B1) (B2)", "RICH"
L = "HO2S1 MNTR (B1) (B2)", "LEAN"
- "HO2S1 (B1) (B2)" voltage goes above 0.6 V at least once.
- "HO2S1 (B1) (B2)" voltage goes below 0.30 V at least once.
- The 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 J43897-18 or J-43897-12 and approved anti-seize lubricant.
Without Consult
1. Start engine and warm it up to normal operating temperature.
2. Set voltmeter probes between ECM terminal (82) (B2), (83) (B1) (sensor signal) and ground.
3. Check the following with engine speed held at 2,000 rpm constant under no load.
- Malfunction indicator lamp goes on more than 5 times within 10 seconds in Diagnostic Test Mode II (HEATED OXYGEN SENSOR 1 MONITOR (FRONT)].
- The maximum voltage is over 0.6 V at least one time.
- The minimum voltage is below 0.30 V at least one time.
- The 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.