Infiniti M45 (Y34). Manual - part 390

DTC P0138, P0158 HO2S2

EC-249

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EC

BANK 2

TBWA0277E

EC-250

DTC P0138, P0158 HO2S2

Specification data are reference values and are measured between each terminal and ground.

CAUTION:

Do not use ECM ground terminals when measuring input/output voltage. Doing so may result in dam-
age to the ECM's transistor. Use a ground other than ECM terminals, such as the ground.

Diagnostic Procedure

ABS002HI

1. 

CHECK GROUND CONNECTIONS

1.

Turn ignition switch OFF.

2.

Loosen and retighten two ground screws. 
Refer to 

EC-141, "Ground Inspection"

 .

OK or NG

OK

>> GO TO 2.

NG

>> Repair or replace ground connections.

2. 

CHECK HO2S2 GROUND CIRCUIT FOR OPEN AND SHORT

1.

Disconnect heated oxygen sensor 2 harness connector.

2.

Check harness continuity between HO2S2 terminal 4 and ground.
Refer to Wiring Diagram.

3.

Also check harness for short to power.

OK or NG

OK

>> GO TO 4.

NG

>> GO TO 3.

TER-

MINAL 

NO.

WIRE 

COLOR

ITEM

CONDITION

DATA (DC Voltage)

124

B

Heated oxygen sensor 2 
(bank 2)

[Engine is running]

●

Revving engine from idle up to 3,000 rpm 
quickly after the following conditions are met.

–

Warm-up condition

–

Keeping the engine speed between 3,500 
and 4,000 rpm for 1 minute and at idle for 1 
minute under no load

0 - Approximately 1.0V

PBIB1118E

Continuity should exist.

PBIB0018E

DTC P0138, P0158 HO2S2

EC-251

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EC

3. 

DETECT MALFUNCTIONING PART

Check the following.

●

Harness connectors E315, F5

●

Joint connector-29

●

Harness open or short between HO2S2 and ground

>> Repair open circuit or short to power in harness or connectors.

4. 

CHECK HO2S2 INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT

1.

Disconnect ECM harness connector.

2.

Check harness continuity between ECM terminal and HO2S2 terminal as follows.
Refer to Wiring Diagram.

3.

Check harness continuity between the following terminals and ground.
Refer to Wiring Diagram.

4.

Also check harness for short to power.

OK or NG

OK

>> GO TO 6.

NG

>> GO TO 5.

5. 

DETECT MALFUNCTIONING PART

Check the following.

●

Harness connectors E315, F5

●

Harness for open or short between HO2S2 and ECM

>> Repair open circuit or short to ground or short to power in harness or connectors.

6. 

CHECK HEATED OXYGEN SENSOR 2

Refer to 

EC-252, "Component Inspection"

 .

OK or NG

OK

>> GO TO 7.

NG

>> Replace malfunctioning heated oxygen sensor 2.

DTC

Terminals

Bank

ECM

Sensor

P0138

123

1

1

P0158

124

1

2

Continuity should exist.

DTC

Terminals

Bank

ECM

Sensor

P0138

123

1

1

P0158

124

1

2

Continuity should not exist.

EC-252

DTC P0138, P0158 HO2S2

7. 

CHECK INTERMITTENT INCIDENT

Refer to 

EC-132, "TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT"

 .

>> INSPECTION END

Component Inspection

ABS002HJ

HEATED OXYGEN SENSOR 2

 With CONSULT-II

1.

Start engine and warm it up to the normal operating temperature.

2.

Turn ignition switch OFF and wait at least 10 seconds.

3.

Start engine and keep engine speed between 3,500 and 4,000 rpm for 1 minute under no load.

4.

Let engine idle for 1 minute.

5.

Select “FUEL INJECTION” in “ACTIVE TEST” mode, and select
“HO2S2 (B1)/(B2)” as the monitor item with CONSULT-II.

6.

Check “HO2S2 (B1)/(B2)” at idle speed when adjusting “FUEL INJECTION” to 

±

25%.

“HO2S2 (B1)/(B2)” should be above 0.58V at least once when the “FUEL INJECTION” is +25%.
“HO2S2 (B1)/(B2)” should be below 0.48V at least once when the “FUEL INJECTION” is 

−

25%.

CAUTION:

●

Discard any heated oxygen sensor which has been dropped from a height of more than 0.5 m (19.7
in) onto a hard surface such as a concrete floor; use a new one.

●

Before installing new oxygen sensor, clean exhaust system threads using Oxygen Sensor Thread
Cleaner tool J-43897-18 or J-43897-12 and approved anti-seize lubricant.

 Without CONSULT-II

1.

Start engine and warm it up to the normal operating temperature.

2.

Turn ignition switch OFF and wait at least 10 seconds.

3.

Start engine and keep engine speed between 3,500 and 4,000 rpm for 1 minute under no load.

4.

Let engine idle for 1 minute.

5.

Set voltmeter probes between ECM terminal 123 [HO2S2 (B1) signal] or 124 [HO2S2 (B2) signal] and
ground.

PBIB1918E

PBIB1153E