Infiniti G37 Coupe. Manual - part 543

P0555 BRAKE BOOSTER PRESSURE SENSOR

EC-353

< COMPONENT DIAGNOSIS >

[VQ37VHR]

C

D

E

F

G

H

I

J

K

L

M

A

EC

N

P

O

Is the inspection result normal?

YES

>> GO TO 2.

NO

>> Replace brake booster pressure sensor.

2.

CHECK BRAKE BOOSTER PRESSURE SENSOR-II

1.

Turn ignition switch OFF.

2.

Remove brake booster pressure sensor with its harness connected.

3.

Connect the hose of vacuum pump (A) to brake booster pres-
sure sensor (1).

4.

Turn ignition switch ON.

5.

Check the voltage between ECM harness connector terminals as follows.

6.

Check that the difference of the voltage when engine is stopped and that when negative pressure is
applied with vacuum pump is within the following limits. 

Is the inspection result normal?

YES

>> INSPECTION END

NO

>> Replace brake booster pressure sensor.

Atmospheric pressure

Voltage

800hPa

3.1 – 3.7V

850hPa

3.3 – 3.9V

900hPa

3.5 – 4.1V

950hPa

3.8 – 4.3V

1000hPa

4.0 – 4.6V

1050hPa

4.2 - 4.8V

JMBIA0870GB

JMBIA0872ZZ

ECM

+

–

Connector

Terminal

Connector

Terminal

F101

39

F101

36

Vacuum

Voltage difference

-40kPa(-300mmHg)

1.5 – 2.0V

-53.3kPa(-400mmHg)

2.0 – 2.6V

-66.7kPa(-500mmHg)

2.6 – 3.2V

-80kPa(-600mmHg)

3.2 – 3.8V

EC-354

< COMPONENT DIAGNOSIS >

[VQ37VHR]

P0603 ECM POWER SUPPLY

P0603 ECM POWER SUPPLY

Description

INFOID:0000000001734167

Battery voltage is supplied to the ECM even when the ignition switch
is turned OFF for the ECM memory function of the DTC memory, the
air-fuel ratio feedback compensation value memory, the idle air vol-
ume learning value memory, etc.

DTC Logic

INFOID:0000000001734168

DTC DETECTION LOGIC

DTC CONFIRMATION PROCEDURE

1.

PRECONDITIONING

If DTC Confirmation Procedure has been previously conducted, always perform the following before conduct-
ing 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.

>> GO TO 2.

2.

PERFORM DTC CONFIRMATION PROCEDURE

1.

Turn ignition switch ON and wait at least 1 second.

2.

Start engine and let it idle for 1 second.

3.

Turn ignition switch OFF, wait at least 10 seconds, and then turn ON.

4.

Repeat steps 2 and 3 for four times.

5.

Check 1st trip DTC.

Is 1st trip DTC detected?

YES

>> Go to 

EC-354, "Diagnosis Procedure"

.

NO

>> INSPECTION END

Diagnosis Procedure

INFOID:0000000001734169

1.

CHECK ECM POWER SUPPLY

1.

Turn ignition switch OFF.

2.

Disconnect ECM harness connector.

3.

Check the voltage between ECM harness connector and ground.

JMBIA0057ZZ

DTC No.

Trouble diagnosis name

DTC detecting condition

Possible cause

P0603

ECM power supply cir-
cuit

ECM back-up RAM system does not function 
properly.

• Harness or connectors

[ECM power supply (back-up) circuit is 
open or shorted.]

• ECM

ECM

Ground

Voltage

Connector

Terminal

F102

93

Ground

Battery voltage

P0603 ECM POWER SUPPLY

EC-355

< COMPONENT DIAGNOSIS >

[VQ37VHR]

C

D

E

F

G

H

I

J

K

L

M

A

EC

N

P

O

Is the inspection result normal?

YES

>> GO TO 3.

NO

>> GO TO 2.

2.

DETECT MALFUNCTIONING PART

Check the following.
• Harness connectors E3, F1
• 15A fuse (No. 50)
• IPDM E/R harness connector E7
• Harness for open or short between ECM and battery

>> Repair or replace harness or connectors.

3.

CHECK INTERMITTENT INCIDENT

Refer to 

GI-38, "Intermittent Incident"

.

Is the inspection result normal?

YES

>> GO TO 4.

NO

>> Repair or replace harness or connectors.

4.

PERFORM DTC CONFIRMATION PROCEDURE

With CONSULT-III

1.

Turn ignition switch ON.

2.

Select “SELF-DIAG RESULTS” mode with CONSULT-III.

3.

Touch “ERASE”.

4.

Perform DTC Confirmation Procedure.
See 

EC-354, "DTC Logic"

.

With GST

1.

Turn ignition switch ON.

2.

Select Service $04 with GST.

3.

Perform DTC Confirmation Procedure.
See 

EC-354, "DTC Logic"

.

Is the 1st trip DTC P0603 displayed again?

YES

>> GO TO 5.

NO

>> INSPECTION END

5.

REPLACE ECM

1.

Replace ECM.

2.

Go to 

EC-16, "ADDITIONAL SERVICE WHEN REPLACING CONTROL UNIT (ECM) : Special Repair

Requirement"

.

>> INSPECTION END

EC-356

< COMPONENT DIAGNOSIS >

[VQ37VHR]

P0605 ECM

P0605 ECM

Description

INFOID:0000000001734170

The ECM consists of a microcomputer and connectors for signal
input and output and for power supply. The ECM controls the engine.

DTC Logic

INFOID:0000000001734171

DTC DETECTION LOGIC

DTC CONFIRMATION PROCEDURE

1.

PRECONDITIONING

If DTC Confirmation Procedure has been previously conducted, always perform the following before conduct-
ing 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.

>> GO TO 2.

2.

PERFORM DTC CONFIRMATION PROCEDURE FOR MALFUNCTION A

1.

Turn ignition switch ON.

2.

Check 1st trip DTC.

Is 1st trip DTC detected?

YES

>> Go to 

EC-357, "Diagnosis Procedure"

.

NO

>> GO TO 3.

3.

PERFORM DTC CONFIRMATION PROCEDURE FOR MALFUNCTION B

1.

Turn ignition switch ON and wait at least 1 second.

2.

Turn ignition switch OFF, wait at least 10 seconds, and then turn ON.

3.

Check 1st trip DTC.

Is 1st trip DTC detected?

YES

>> Go to 

EC-357, "Diagnosis Procedure"

.

NO

>> GO TO 4.

4.

PERFORM DTC CONFIRMATION PROCEDURE FOR MALFUNCTION C

1.

Turn ignition switch ON and wait at least 1 second.

2.

Turn ignition switch OFF, wait at least 10 seconds, and then turn ON.

3.

Repeat step 2 for 32 times.

4.

Check 1st trip DTC.

Is 1st trip DTC detected?

JMBIA0057ZZ

DTC No.

Trouble diagnosis name

DTC detecting condition

Possible cause

P0605

Engine control module

A)

ECM calculation function is malfunctioning.

• ECM

B)

ECM EEP-ROM system is malfunctioning.

C)

ECM self shut-off function is malfunctioning.