DTC P0138:00 [SKYACTIV-G 1.5, SKYACTIV-G 2.0, SKYACTIV-G 2.5]

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Note
•  To determine the malfunctioning part, proceed with the diagnostics from "Function Inspection Using M-MDS".

Details On DTCs

DESCRIPTION

HO2S circuit high input
DETECTION CONDITION
Determination conditions
•  A condition in which the HO2S input voltage exceeds the specified value continues for the specified period.
Preconditions
•  Not applicable
Malfunction determination period
•  5 s period
Drive cycle
•  2
Self test type
•  CMDTC self test, KOEO self test, KOER self test
Sensor used
•  HO2S
FAIL-SAFE FUNCTION
•  Not applicable
VEHICLE STATUS WHEN DTCs ARE OUTPUT
•  Illuminates check engine light.
POSSIBLE CAUSE
•  HO2S connector or terminals malfunction
•  PCM connector or terminals malfunction
•  Short to power supply in wiring harness between the following terminals:
―  HO2S terminal A—PCM terminal 2AI
―  HO2S terminal B—PCM terminal 2AG
•  HO2S malfunction
•  PCM malfunction


System Wiring Diagram

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Function Explanation (DTC Detection Outline)

•  The PCM detects the oxygen concentration in the exhaust gas based on the HO2S signal. The PCM determines a HO2S signal error based on the condition in which the HO2S input voltage continues to exceed the specified value, and stores a DTC.

Repeatability Verification Procedure

1.  Warm up the engine to allow the engine coolant temperature to reach 80 °C {176 °F} or more.
2.  Start the engine and leave it idling for 1 min.
Note
•  Match the engine coolant temperature in the recorded FREEZE FRAME DATA (Mode 2)/snapshot data, the vehicle speed, and engine speed values to the best extent possible while driving the vehicle.
3.  Try to reproduce the malfunction by driving the vehicle for 5 min based on the values in the FREEZE FRAME DATA (Mode 2)/snapshot data.

PID Item/Simulation Item Used In Diagnosis

•  Not applicable

Function Inspection Using M-MDS

STEP

INSPECTION

RESULTS

ACTION
1
PURPOSE: VERIFY RELATED SERVICE INFORMATION AVAILABILITY
•  Verify related Service Information availability.
•  Is any related Service Information available?
Yes
Perform repair or diagnosis according to the available Service Information.
•  If the vehicle is not repaired, go to the next step.
No
Go to the next step.
2
PURPOSE: RECORD VEHICLE STATUS AT TIME OF DTC DETECTION TO UTILIZE WITH REPEATABILITY VERIFICATION
•  Has the FREEZE FRAME DATA (Mode 2)/snapshot data been recorded?
Yes
Go to the troubleshooting procedure to perform the procedure from Step 1.
No
Record the FREEZE FRAME DATA (Mode 2)/snapshot data on the repair order.
Note
•  Recording can be facilitated using the screen capture function of the PC.
Go to the troubleshooting procedure to perform the procedure from Step 1.


Troubleshooting Diagnostic Procedure

Intention of troubleshooting procedure
•  Step 1—2
―  Perform an inspection of the HO2S and PCM-related connectors.
•  Step 3
―  Perform an inspection of the short to power supply in wiring harness between HO2S and PCM.
•  Step 4
―  Perform a unit inspection of the HO2S.
•  Step 5—6
―  Verify that the primary malfunction is resolved and there are no other malfunctions.

STEP

INSPECTION

RESULTS

ACTION
1
PURPOSE: INSPECT HO2S CONNECTOR CONDITION
•  Switch the ignition off.
•  Disconnect the HO2S connector.
•  Inspect for poor connection (such as damaged/pulled-out pins, corrosion).
•  Is there any malfunction?
Yes
Replace the HO2S, then go to Step 5.
(See HEATED OXYGEN SENSOR (HO2S) REMOVAL/INSTALLATION [SKYACTIV-G 1.5, SKYACTIV-G 2.0, SKYACTIV-G 2.5].)
No
Go to the next step.
2
PURPOSE: INSPECT PCM CONNECTOR CONDITION
•  Disconnect the PCM connector.
•  Inspect for poor connection (such as damaged/pulled-out pins, corrosion).
•  Is there any malfunction?
Yes
Replace the PCM, then go to Step 5.
(See PCM REMOVAL/INSTALLATION [SKYACTIV-G 1.5, SKYACTIV-G 2.0, SKYACTIV-G 2.5].)
No
Go to the next step.
3
PURPOSE: INSPECT HO2S CIRCUIT FOR SHORT TO POWER SUPPLY
•  Verify that the HO2S and PCM connectors are disconnected.
•  Switch the ignition ON (engine off).
Note
•  Another DTC may be stored by the PCM detecting an open circuit.
•  Measure the voltage at the following terminals (wiring harness-side):
―  HO2S terminal A
―  HO2S terminal B
•  Is the voltage 0 V?
Yes
Go to the next step.
No
Refer to the wiring diagram and verify whether or not there is a common connector between the following terminals:
•  HO2S terminal A—PCM terminal 2AI
•  HO2S terminal B—PCM terminal 2AG
If there is a common connector:
•  Determine the malfunctioning part by inspecting the common connector and the terminal for corrosion, damage, or pin disconnection, and the common wiring harness for a short to power supply.
•  Repair or replace the malfunctioning part.
If there is no common connector:
•  Repair or replace the wiring harness which has a short to power supply.
Go to Step 5.
4
PURPOSE: DETERMINE INTEGRITY OF HO2S
•  Reconnect all disconnected connectors.
•  Inspect the HO2S.
•  Is there any malfunction?
Yes
Replace the HO2S, then go to the next step.
(See HEATED OXYGEN SENSOR (HO2S) REMOVAL/INSTALLATION [SKYACTIV-G 1.5, SKYACTIV-G 2.0, SKYACTIV-G 2.5].)
No
Go to the next step.
5
PURPOSE: VERIFICATION OF VEHICLE REPAIR COMPLETION
•  Always reconnect all disconnected connectors.
•  Clear the DTC from the PCM memory using the M-MDS.
•  Perform the KOEO or KOER self test.
•  Is the PENDING CODE for this DTC present?
Yes
Repeat the inspection from Step 1.
•  If the malfunction recurs, replace the PCM.
Go to the next step.
No
Go to the next step.
6
PURPOSE: VERIFY IF THERE IS ANY OTHER MALFUNCTION
•  Is any other DTC or pending code stored?
Yes
Go to the applicable DTC inspection.
(See DTC TABLE [SKYACTIV-G 1.5, SKYACTIV-G 2.0, SKYACTIV-G 2.5].)
No
DTC troubleshooting completed.