P0138
DTC P0138: Heated Oxygen Sensor Circuit High Voltage (bank 1, sensor 2)Right Bank Heated Oxygen Sensor (rear) Circuit Part 1:
Right Bank Heated Oxygen Sensor (rear) Circuit Part 2:
CIRCUIT OPERATION
- A voltage corresponding to the oxygen concentration in the exhaust gas is sent to the ECM (terminal 74)
- Terminal 2 of the right bank heated oxygen sensor (rear) is grounded with ECM (terminal 49)
TECHNICAL DESCRIPTION
- The output signal of the right bank heated oxygen sensor (front) is compensated by the output signal of the right bank heated oxygen sensor (rear).
- The ECM
DTC SET CONDITIONS
Check Conditions
- 2 seconds or more have passed since the starting sequence was completed.
Judgment Criteria
- Right bank heated oxygen sensor (rear) output voltage has continued to be 1.2 volts or higher for 2 seconds.
TROUBLESHOOTING HINTS (The most likely causes for this code to be set are:)
- Short circuit in right bank heated oxygen sensor (rear) ground line.
- ECM failed.
- PCM failed.
DIAGNOSIS
Required Special Tool:
- MB991502: Scan Tool (MUT-II)
STEP 1. Check connector B-28 at right bank heated oxygen sensor (rear) and connector C-62 at ECM
Q: Is the connector in good condition?
YES: Go to Step 2.
NO: Repair or replace it. Refer to Harness Connector Inspection. Then go to Step 3.
STEP 2. Check for short circuit to power supply between right bank heated oxygen sensor (rear) connector B-28 terminal 4 and ECM connector C-62 terminal 74
Q: Is the harness wire in good condition?
YES: Replace the ECM or PCM. Then 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 Procedure 6 - Other Monitor.
2. Check the diagnostic trouble code (DTC).
Q: Is the DTC P0138 is output?
YES: Retry the troubleshooting.
NO: The inspection is complete.