P0145
DTC P0145: Heated Oxygen Sensor Circuit Slow Response (bank 1, sensor 3)Center Exhaust Pipe Heated Oxygen Sensor Circuit Part 1:
Center Exhaust Pipe Heated Oxygen Sensor Circuit Part 2:
CIRCUIT OPERATION
A voltage corresponding to the oxygen concentration in the exhaust gas is sent to the ECM (terminal No. 101) from the output terminal (terminal No. 3) of the center exhaust pipe heated oxygen sensor.
Terminal No. 4 of the center exhaust pipe heated oxygen sensor is grounded with ECM (terminal No. 116).
The ECM applies an offset voltage of 0.5 volt to terminal No. 4 of the center exhaust pipe heated oxygen sensor.
TECHNICAL DESCRIPTION
The ECM checks for the center exhaust pipe heated oxygen sensor output voltage.
DESCRIPTIONS OF MONITOR METHODS
Center exhaust pipe heated oxygen sensor output voltage does not reach 0.2 volt after fuel cut operation.
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)
Heated oxygen sensor heater (front) monitor
Center exhaust pipe heated oxygen sensor heater
Air/fuel ratio feedback monitor
Sensor (The sensor below is determined to be normal)
Mass airflow sensor
Engine coolant temperature sensor
DTC SET CONDITIONS
Logic Flow Chart:
Logic Flow Chart
Check Conditions
Engine coolant temperature is higher than 76 °C (169 °F).
The center exhaust pipe heated oxygen sensor (front) is active.
The cumulative mass airflow sensor output is higher than 2,900 g.
Fuel is being shut off.
Judgement Criterion
Center exhaust pipe oxygen sensor output voltage does not reach 0.2 volt for 7 seconds from fuel cut start. OBD-II DRIVE CYCLE PATTERN Refer to Diagnostic Function - OBD-II Drive Cycle - Pattern 11. OBD-II Drive Cycle
TROUBLESHOOTING HINTS (The most likely causes for this code to be set are:)
Center exhaust pipe heated oxygen sensor failed.
DIAGNOSIS
Required Special Tools:
- MB991958: Scan Tool (M.U.T.-III Sub Assembly)
- MB991824: V.C.I.
- MB991827: USB Cable
- MB991910: Main Harness A
STEP 1. Using scan tool MB991958, check data list item AD: Heated Oxygen Sensor Bank 1, Sensor 3 (center exhaust).
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 B1, Heated Oxygen Sensor Bank 1, Sensor 3 (center exhaust pipe).
4. Warm up the engine.
After increasing the output voltage 0.5 volt or more by the engine revving, finish it. Then confirm that the output voltage reduces to 0.2 volt or less within 6 seconds.
5. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the sensor operating properly?
YES: It can be assumed that this malfunction is intermittent.
NO: Replace the center exhaust pipe heated oxygen sensor. Then go to Step 2.
STEP 2. 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 11. OBD-II Drive Cycle
2. Check the diagnostic trouble code (DTC).
Q: Is DTC P0145 set?
YES: Refer to DTC P0145 - Heated Oxygen Sensor Circuit Low Voltage (bank 1, sensor 3), DTC P0144 - Heated Oxygen Sensor Circuit High Voltage (bank 1, sensor 3).
NO: The inspection is complete.