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DTC P0138:00 [PCM (SKYACTIV-G 2.0)]

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2016 – MX-5 – Engine

DTC P0138:00 [PCM (SKYACTIV-G 2.0)]

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

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

  • Warm up the engine to allow the engine coolant temperature to reach 80 °C {176 °F} or more.

  • Start the engine and leave it idling for 1 min.

    NOTE:

    • Match the engine coolant temperature in the recorded FREEZE FRAME DATA/snapshot data, the vehicle speed, and engine speed values to the best extent possible while driving the vehicle.

  • Try to reproduce the malfunction by driving the vehicle for 5 min based on the values in the FREEZE FRAME DATA/snapshot data.

PID Item/Simulation Item Used In Diagnosis

  • Not applicable

Function Inspection Using M-MDS

STEP

INSPECTION

RESULTS

ACTION

1

 PURPOSE: VERIFY RELATED REPAIR INFORMATION AVAILABILITY

  • Verify related Service Bulletins and/or on-line repair information availability.

  • Is any related repair information available?

Yes

Perform repair or diagnosis according to the available repair information.

  • If the vehicle is not repaired, go to the next step.

No

Go to the next step.

2

 PURPOSE: RECORD FREEZE FRAME DATA/SNAPSHOT DATA AND DIAGNOSTIC MONITORING TEST RESULTS TO UTILIZE WITH REPEATABILITY VERIFICATION

NOTE:

  • Recording can be facilitated using the screen capture function of the PC.

  • Record the FREEZE FRAME DATA/snapshot data and DIAGNOSTIC MONITORING TEST RESULTS (A/F sensor, HO2S related) on the repair order.

—

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 2.0].)

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 2.0].)

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

Yes

Replace the HO2S, then go to the next step.

(See HEATED OXYGEN SENSOR (HO2S) REMOVAL/INSTALLATION [SKYACTIV-G 2.0].)

No

Go to the next step.

5

 PURPOSE: VERIFICATION OF VEHICLE REPAIR COMPLETION

Yes

Repeat the inspection from Step 1.

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 [PCM (SKYACTIV-G 2.0)].)

No

DTC troubleshooting completed.

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