P0144
DTC P0144: Heated Oxygen Sensor Circuit High Voltage (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 is over the specified range.
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) Not applicable.
Sensor (The sensor below is determined to be normal)
Not applicable.
DTC SET CONDITION
Logic Flow Chart:
Logic Flow Chart
Check Conditions
2 seconds or more have passed since the engine starting sequence was completed.
Heated oxygen sensor off set voltage is between 0.4 and 0.6 volt.
Judgement Criterion
Center exhaust pipe Heated oxygen sensor output voltage has continued to be 1.8 volts or higher for 2 seconds.
OBD-II DRIVE CYCLE PATTERN
Refer to Diagnostic Function - OBD-II Drive Cycle - Pattern 24. OBD-II Drive Cycle
TROUBLESHOOTING HINTS (The most likely causes for this code to be set are: )
Connector damage.
Harness damage
ECM 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. Check harness connector D-30 at the center exhaust pipe heated oxygen sensor and harness connector D-30 at ECM for damage.
Q: Is the harness connector in good condition?
YES: Go to Step 2.
NO: Repair it. Then go to Step 3.
STEP 2. Check for short circuit to power supply between the center exhaust pipe heated oxygen sensor connector D-30 (terminal No. 3) and the ECM connector B-11 (terminal No. 101).
Q: Is the harness wire in good condition?
YES: Go to Step 3.
NO: Repair it. Then go to Step 3.
STEP 3. 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 24. OBD-II Drive Cycle
2. Check the diagnostic trouble code (DTC).
Q: Is DTC P0138 set?
YES: Replace the ECM. When the ECM is replaced, register the ID code. Refer to ID Code Registration Judgment Table
NO: It can be assumed that this malfunction is intermittent.