P0154
DTC P0154: Cylinder 2, 3 Heated Oxygen Sensor (front) No Activity DetectedCAUTION: If DTC P0154 has been set, TCL related DTC U1120 is also set. After P0154 has been diagnosed, don't forget to erase DTC U1120.
Cylinder 2, 3 Heated Oxygen Sensor (front) No Activity Detected Circuit
- Refer to DTC P0151 - Cylinder 2, 3 Heated Oxygen Sensor (front) Circuit Low Voltage. P0151
- Refer to DTC P0202 - Injector Circuit-cylinder 2. P0202
- Refer to DTC P0203 - Injector Circuit-cylinder 3. P0203
CIRCUIT OPERATION
- Refer to DTC P0151 - Cylinder 2, 3 Heated Oxygen Sensor (front) Circuit Low Voltage. P0151
- Refer to DTC P0202 - Injector Circuit-cylinder 2. P0202
- Refer to DTC P0203 - Injector Circuit-cylinder 3. P0203
TECHNICAL DESCRIPTION
- The PCM effects air/fuel ratio feedback control in accordance with the signals from the cylinder 2, 3 heated oxygen sensor (front).
- If the cylinder 2, 3 heated oxygen sensor (front) has deteriorated, corrections will be made by the cylinder 2, 3 heated oxygen sensor (rear).
- DTC P0154 becomes stored in memory if a failure is detected in the above air/fuel ratio feedback control system.
DESCRIPTIONS OF MONITOR METHODS
Cylinder 2, 3 heated oxygen sensor (front) output voltage does not cross lean/rich criteria (about 0.5 volt) within specified period.
MONITOR EXECUTION
Continuous
MONITOR EXECUTION CONDITIONS (Other monitor and Sensor)
Other Monitor (There is no temporary DTC stored in memory for the item monitored below)
- Misfire monitor
Sensor (The sensor below is determined to be normal)
- Mass airflow sensor
- Engine coolant temperature sensor
- Intake air temperature sensor
- Barometric pressure sensor
- Throttle position sensor
DTC SET CONDITIONS
Logic Flow Chart:
Check Conditions
- 20 seconds or more have passed since the engine starting sequence was completed.
- Engine coolant temperature is higher than 7 °C (45 °F).
- Engine speed is higher than 1,200 r/min.
- Volumetric efficiency is higher than 30 percent.
- Throttle position sensor output voltage is lower than 4 volts.
- Except while fuel is being shut off.
- Monitoring time: 30 seconds.
Judgement Criterion
- Cylinder 2, 3 heated oxygen sensor (front) output voltage does not get across lean/rich criteria (about 0.5 volt) within about 30 seconds.
OBD-II DRIVE CYCLE PATTERN
Refer to Diagnostic Function - OBD-II Drive Cycle - Pattern 12. OBD-II Drive Cycle
TROUBLESHOOTING HINTS (The most likely causes for this code to be set are: )
- Cylinder 2, 3 heated oxygen sensor (front) deteriorated.
- Harness damage in cylinder 2, 3 heated oxygen sensor (front) output line.
- Cylinder 2, 3 heated oxygen sensor (rear) deteriorated.
NOTE: When the cylinder 2, 3 heated oxygen sensor (front) begins to deteriorate, the heated oxygen sensor output voltage will deviate from the voltage when the sensor was new (normally 0.5 volt at stoichiometric ratio). This deviation will be corrected by the cylinder 2, 3 heated oxygen sensor (rear).
If the cylinder 2, 3 heated oxygen sensor (rear) responds poorly because it has deteriorated, it will improperly correct the cylinder 2, 3 heated oxygen sensor (front). Thus, even when closed loop control is being effected, the fluctuation of the cylinder 2, 3 heated oxygen sensor (front) output voltage decreases, without intersecting with 0.5 volt. As a result, there is a possibility of DTC P0154 becoming registered.
- Open circuit in cylinder 2, 3 injector.
- Harness damage in cylinder 2, 3 injector circuit.
- Connector damage.
- PCM failed.
- Exhaust leak.
- Air drawn in from gaps in gasket, seals, etc.
- Incorrect fuel pressure.
DIAGNOSIS
Required Special Tools:
- MB991958: Scan Tool (M.U.T.-III Sub Assembly)
- MB991824: V.C.I.
- MB991827: USB Cable
- MB991910: Main Harness A
- MB991316: Test Harness
STEP 1. Using scan tool MB991958, check data list item AF: Cylinder 2, 3 Heated Oxygen Sensor (rear).
CAUTION: To prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991958.
1. Connect scan tool MB991958 to the data link connector.
2. Start the engine and run at idle.
3. Set scan tool MB991958 to the data reading mode for item AF, Cylinder 2, 3 Heated Oxygen Sensor (rear).
a. Transaxle: "L" range
b. Drive with wide open throttle
c. Engine: 3,500 r/min
- The output voltage should be between 0.6 and 1.0 volt.
4. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the sensor operating properly?
YES : Go to Step 2.
NO : Refer to DTC P0157 - Cylinder 2, 3 Heated Oxygen Sensor (rear) Circuit Low Voltage, DTC P0158 - Cylinder 2, 3 Heated Oxygen Sensor (rear) Circuit High Voltage, DTC P0159 - Cylinder 2, 3 Heated Oxygen Sensor (rear) Circuit Slow Response, DTC P0160 - Cylinder 2, 3 Heated Oxygen Sensor (rear) Circuit No Activity Detected.
P0157
P0158
P0159
P0160
STEP 2. Check for exhaust leak.
Q: Are there any abnormalities?
YES : Repair it. Then go to Step 12.
NO : Go to Step 3.
STEP 3. Check for intake system vacuum leak.
Q: Are there any abnormalities?
YES : Repair it. Then go to Step 12.
NO : Go to Step 4.
STEP 4. Check harness connector B-36 at the cylinder 2, 3 heated oxygen sensor (front) for damage.
Q: Is the harness connector in good condition?
YES : Go to Step 5.
NO : Repair or replace it. Then go to Step 12.
STEP 5. Check the cylinder 2, 3 heated oxygen sensor (front).
1. Disconnect the cylinder 2, 3 heated oxygen sensor (front) connector B-36 and connect test harness special tool MB991316 to the connector on the cylinder 2, 3 heated oxygen sensor (front) side.
2. Warm up the engine until engine coolant temperature reaches 80 °C (176 °F) or higher.
3. Rev the engine for 5 minutes or more with the engine speed of 2,000 r/min.
4. Connect a digital voltage meter between terminal No. 2 (black clip) and terminal No. 4 (white clip).
5. While repeatedly revving the engine, measure the cylinder 2, 3 heated oxygen sensor (front) output voltage.
Standard value: 0.6 - 1.0 V
CAUTION:
- Be very careful when connecting the jumper wires; incorrect connection can damage the heated oxygen sensor.
- Be careful the heater can be damaged if a voltage beyond 8 volts is applied to the heated oxygen sensor heater.
NOTE: If the temperature of sensing area does not reach the high temperature [of approximately 400 °C (752 °F) or more] even though the oxygen sensor is normal, the output voltage would be possibly low in spite of the rich air-fuel ratio. Therefore, if the output voltage is low, use a jumper wire to connect the terminal No. 1 (red clip) and the terminal No. 3 (blue clip) of the heated oxygen sensor with the positive terminal and the negative terminal of 8 volts power supply respectively, then check again.
Q: Is the measured voltage between 0.6 and 1.0 volt?
YES : Go to Step 6.
NO : Replace the cylinder 2, 3 heated oxygen sensor (front). Then go to Step 12.
STEP 6. Check harness connector B-03, B-30 at injector for damage.
Q: Is the harness connector in good condition?
YES : Go to Step 7.
NO : Repair or replace it. Then go to Step 12.
STEP 7. Check the cylinder 2, 3 injector.
1. Disconnect each injector connector.
2. Measure the resistance between injector side connector terminal No. 1 and No. 2.
Standard value: 10.5 - 13.5 ohms [at 20 °C (68 °F)]
Q: Is the measured resistance between 10.5 and 13.5 ohms [at 20 °C (68 °F)]?
YES : Go to Step 8.
NO : Replace the injector. Then go to Step 12.
STEP 8. Check harness connector B-22, B-23 at PCM for damage.
Q: Is the harness connector in good condition?
YES : Go to Step 9.
NO : Repair or replace it. Then go to Step 12.
STEP 9. Check for harness damage between cylinder 2, 3 heated oxygen sensor (front) connector B-36 (terminal No. 4) and PCM connector B-22 (terminal No. 91).
Q: Is the harness wire in good condition?
YES : Go to Step 10.
NO : Repair it. Then go to Step 12.
STEP 10. Check for harness damage between cylinder 2, 3 injector connector and PCM connector.
a. Check the harness wire between injector connector B-30 (terminal No. 2) and PCM connector B-23 (terminal No. 146) at No. 2 cylinder.
b. Check the harness wire between injector connector B-03 (terminal No. 2) and PCM connector B-23 (terminal No. 140) at No. 3 cylinder.
Q: Is the harness wire in good condition?
YES : Go to Step 11.
NO : Repair it. Then go to Step 12.
STEP 11. Check the fuel pressure.
Refer to On-vehicle Service - Fuel Pressure Test. Testing and Inspection
Q: Is the fuel pressure normal?
YES : Replace the PCM. When the PCM is replaced, register the encrypted code. Then go to Step 12.
NO : Repair it. Then go to Step 12.
STEP 12. Test the OBD-II drive cycle.
1. Carry out a test drive with the drive cycle pattern. Refer to Diagnostic Function - OBD-II Drive Cycle - Pattern 12. OBD-II Drive Cycle
2. Check the diagnostic trouble code (DTC).
Q: Is DTC P0154 set?
YES : Retry the troubleshooting.
NO : The inspection is complete.