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DTC Description
 
 
DTC DETECTION LOGIC
The heated oxygen sensor 2 has a much longer switching time between rich and lean than the air fuel ratio (A/F) sensor 1. The oxygen storage capacity of the three way catalyst (manifold) causes the longer switching time.
MALFUNCTION A
To judge the malfunctions of heated oxygen sensor 2, ECM monitors whether the voltage is unusually high during the various driving condition such as fuel-cut.
MALFUNCTION B
To judge the malfunctions of heated oxygen sensor 2, ECM monitors whether the minimum voltage of sensor is sufficiently low during the various driving condition such as fuel-cut.
DTCM.U.T.-III SE screen terms
(Trouble diagnosis content)
DTC detection condition
P013800O2 sensor bank 1 sensor2(B1)
(O2 sensor circuit high voltage bank 1 sensor 2)
ADiagnosis condition—
Signal (terminal)Heated oxygen sensor 2 signal
ThresholdAn excessively high voltage from the sensor is sent to ECM
Diagnosis delay time—
BDiagnosis condition—
Signal (terminal)Heated oxygen sensor 2 signal
ThresholdThe minimum voltage from the sensor is not reached to the specified voltage
Diagnosis delay time—
 
 
POSSIBLE CAUSE
 
 
P0138-A
  • Harness or connectors (The heated oxygen sensor 2 circuit is open or shorted.)
  • Heated oxygen sensor 2
 
 
P0138-B
  • Harness or connectors (The heated oxygen sensor 2 circuit is open or shorted.)
  • Heated oxygen sensor 2
  • Fuel pressure
  • Fuel injector
 
 
FAIL-SAFE
Not applicable
 
 
DTC Confirmation Procedure
1.PRECONDITIONING
If DTC Confirmation Procedure has been previously conducted, always perform the following procedure before conducting the next test.
  1. Turn ignition switch OFF and wait at least 10 seconds.
  2. Turn ignition switch ON.
  3. Turn ignition switch OFF and wait at least 10 seconds.
: .
 
2.PERFORM DTC CONFIRMATION PROCEDURE FOR MALFUNCTION A
  1. Start engine and warm it up to normal operating temperature.
  2. Turn ignition switch OFF and wait at least 10 seconds.
  3. Start engine and keep the engine speed between 3,500 and 4,000 rpm for at least 1 minute under no load.
  4. Let engine idle for 2 minutes.
  5. Check 1st trip DTC.
Is 1st trip DTC detected?
Proceed to DTC Diagnosis Procedure.
-1With M.U.T.-III SE: .
-2Without M.U.T.-III SE: .
 
3.PERFORM DTC CONFIRMATION PROCEDURE FOR MALFUNCTION B
noteFor better results, perform “DTC WORK SUPPORT” at a temperature of 0 to 30°C (32 to 86°F).
  1. Turn ignition switch ON and select “DATA MONITOR” mode of “ENGINE” using M.U.T.-III SE.
  2. Start engine and warm it up to normal operating temperature.
  3. Turn ignition switch OFF and wait at least 10 seconds.
  4. Start engine and keep the engine speed between 3,500 and 4,000 rpm for at least 1 minute under no load.
  5. Let engine idle for 1 minute.
  6. Make sure that “COOLANT TEMP/S” indication is more than 70°C (158°F).
    If not, warm up engine and go to next step when “COOLANT TEMP/S” indication reaches 70°C (158°F).
  7. Open engine hood.
  8. Select “HO2S2 (B1) P1146” of “HO2S2” in “DTC WORK SUPPORT” mode of “ENGINE” using M.U.T.-III SE.
  9. Follow the instruction of M.U.T.-III SE.
    noteIt will take at most 10 minutes until “COMPLETED” is displayed.
  10. Touch “SELF-DIAG RESULT”.
Which is displayed on M.U.T.-III SE
INSPECTION END
Proceed to DTC Diagnosis Procedure.
: .
 
4.PERFORM DTC CONFIRMATION PROCEDURE FOR MALFUNCTION B AGAIN
  1. Turn ignition switch OFF and leave the vehicle in a cool place (soak the vehicle).
  2. Perform DTC confirmation procedure again.
: .
 
5.PERFORM COMPONENT FUNCTION CHECK FOR MALFUNCTION B
Perform component function check. Refer to Component Function Check.
noteUse component function check to check the overall function of the heated oxygen sensor 2 circuit. During this check, a 1st trip DTC might not be confirmed.
Is the inspection result normal?
-1To check malfunction symptom before repair: Refer to Intermittent IncidentIntermittent Incident.
-2Confirmation after repair: INSPECTION END
Proceed to DTC Diagnosis Procedure.