DTC P0138:00 [SKYACTIV-G 2.5]

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2014 - Mazda6 - Engine

DTC P0138:00 [SKYACTIV-G 2.5]

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 (Mode 2)/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 (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 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.
1		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.
2		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	Repair or replace the connector and/or terminals, then go to Step 5.
1		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	Repair or replace the connector and/or terminals, then go to Step 5.
2		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). 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.
3		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. (See HEATED OXYGEN SENSOR (HO2S) INSPECTION [SKYACTIV-G 2.5].) Is there any malfunction?	Yes	Replace the HO2S, then go to the next step. (See HEATED OXYGEN SENSOR (HO2S) REMOVAL/INSTALLATION [SKYACTIV-G 2.5].)
4		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. (See CLEARING DTC [SKYACTIV-G 2.5].) Perform the KOEO or KOER self test. (See KOEO/KOER SELF TEST [SKYACTIV-G 2.5].) Is the PENDING CODE for this DTC present?	Yes	Repeat the inspection from Step 1. If the malfunction recurs, replace the PCM. (See PCM REMOVAL/INSTALLATION [SKYACTIV-G 2.5].) Go to the next step.
5		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 2.5].)
6		No	DTC troubleshooting completed.

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