P0150
Left Bank Heated Oxygen Sensor (front ) Circuit:
CIRCUIT OPERATION
- A voltage corresponding to the oxygen concentration in the exhaust gas is sent to the ECM (terminal 71)
- Terminal 2 of the left bank heated oxygen sensor (front) is grounded with ECM (terminal 49)
TECHNICAL DESCRIPTION
- The left bank heated oxygen sensor (front) detects the concentration of oxygen in the exhaust gas; it converts that data to voltage, and sends it to the ECM
- When the left bank heated oxygen sensor (front) begins to deteriorate, the heated oxygen sensor signal response deteriorates also.
- The ECM
DTC SET CONDITIONS
Check Conditions
- Left bank heated oxygen sensor (front) signal voltage has continued to be 0.2 volt or lower for three minutes or more after engine start.
- Engine coolant temperature is higher than 82°C (180°F).
- Engine speed is higher than 1,200 r/min.
- Volumetric efficiency is higher than 25 percent.
- Monitoring time: 7 seconds.
Judgment Criteria
- Input voltage supplied to the ECM
- Only one monitor during one drive cycle
Check Conditions
- Engine coolant temperature is higher than 50°C (176°F).
- Engine speed is at between 1,250 and 3,000 r/min.
- Volumetric efficiency is at between 20 and 60 percent.
- Intake air temperature is higher than -10°C (14°F).
- Barometric pressure is higher than 76 kPa (11 psi).
- Under the closed loop air/fuel control.
- Vehicle speed is 30 km/h (18.7 mph) or more.
- Throttle valve opening angle (TPS output voltage) fluctuates within 0.117 V every 250 milliseconds.
- Monitoring time: 5 - 20 seconds.
Judgment Criteria
- When the air/fuel ratio is forcibly changed (lean to rich), the left bank heated oxygen sensor (front) signal does not respond within 0.95 seconds.
or
- The left bank heated oxygen sensor (front) sends "lean" and "rich" signals alternately eleven times or less for 12 seconds.
- Three monitors during one drive cycle
NOTE: If the sensor switch time is longer than the Judgment Criteria due to the MUT-II OBD-II test Mode - HO2S Test Results, it is assumed that the heated oxygen sensor has deteriorated. If it is short, it is assumed that the harness wire is broken or has a short circuit.
If the heated oxygen sensor signal voltage has not changed even once (lean/rich) after the DTC was erased, the sensor switch time will display as 0 seconds.
TROUBLESHOOTING HINTS
The most likely causes for this code to be set are:
- Left bank heated oxygen sensor (front) deteriorated.
- Open circuit in left bank heated oxygen sensor (front) output line.
- Open circuit in left bank heated oxygen sensor (front) ground line.
- ECM failed.
- PCM failed.
DIAGNOSIS
Required Special Tool:
MB991502: Scan Tool (MUT-II)
MD998464: Test Harness
CAUTION: To prevent damage to scan tool MB991502, always turn the ignition switch to "LOCK" (OFF) position before connecting or disconnecting scan tool MB991502.
STEP 1. Using scan tool MB991502, check data list item 39: Heated Oxygen Sensor (front).
1. Connect scan tool MB991502 to the data link connector.
2. Start the engine and run at idle.
3. Set scan tool MB991502 to the data reading mode for item 39, Heated Oxygen Sensor (front).
- Warm up the engine. When the engine is decelerated suddenly from 4000 r/min, the output voltage should increase from 200 mV or less to 600 - 1000 mV in a few seconds.
- Warm up the engine. When the engine speed is 2000 r/min, more than 0.5 volt and less than 0.5 volt should alternate five times of more within 10 seconds.
4. If the checks above meet the specification, this malfunction is intermittent. Refer to How to Use Troubleshooting/Inspection Service Points - How to Cope With Intermittent Malfunction.
If the checks above do not meet the specification, go to Step 2.
STEP 2. Check the left bank heated oxygen sensor (front).
1. Disconnect the left bank heated oxygen sensor connector (front) B-24 and connect test harness special tool, MD998464, to the connector on the left bank heated oxygen sensor (front) side.
2. Warm up the engine until engine coolant is 80°C (176°F) or higher.
CAUTION: Be very careful when connecting the jumper wires; incorrect connection can damage the left bank heated oxygen sensor (front).
3. Use the jumper wires to connect terminal 1 (red clip) of the left bank heated oxygen sensor (front) connector to the positive battery terminal and terminal 3 (blue clip) to the negative battery terminal.
4. Connect a digital voltage meter between terminal 2 (black clip) and terminal 4 (white clip).
5. While repeatedly revving the engine, measure the left bank heated oxygen sensor (front) output voltage.
Standard value: 0.6 - 1.0 V
If within specifications, go to Step 3.
If not within specifications, replace the left bank heated oxygen sensor (front). Then go to Step 7.
STEP 3. Check harness connector B-24 at the left bank heated oxygen sensor (front) for damage.
If harness connector B-24 is in good condition, go to Step 4.
If harness connector B-24 is damaged, repair or replace it. Refer to Harness Connector Inspection. Then go to Step 7.
STEP 4. Check harness connectors C-58, C-62, at the ECM
If harness connectors C-58, C-62
If harness connectors C-58, C-62
Refer to Harness Connector Inspection. Then go to Step 7.
STEP 5. Check the harness wire between the left bank heated oxygen sensor (front) connector B-24 and ECM connectors C-58, C-62
If the wire between the heated oxygen sensor (front) connector
B-24 and the ECM connectors C-58, C-62
If the wire between the left bank heated oxygen sensor (front) connector B-24 and the ECM connectors C-58, C-62
STEP 6. Replace the left bank heated oxygen sensor (front).
1. Replace the left bank heated oxygen sensor (front).
2. Carry out a test drive with the drive cycle pattern. Refer to Procedure 4 Heated Oxygen Sensor Monitor and Procedure 6 - Other Monitor.
3. Check for the diagnostic trouble code (DTC).
If DTC P0150 is not output, the inspection is complete.
If DTC P0150 is output, replace the ECM or PCM. Then go to Step 7.
STEP 7. Test the OBD-II drive cycle.
1. Carry out a test drive with the drive cycle pattern. Refer to Procedure 4 - Heated Oxygen Monitor and Procedure 6 - Other Monitor.
2. Read the diagnostic trouble code, and confirm that diagnostic trouble code P0150 does not reset.