Infiniti G35 (V35) Sedan. Manual - part 547

EC-334

< COMPONENT DIAGNOSIS >

[VQ35HR]

P0550 PSP SENSOR

P0550 PSP SENSOR

Description

INFOID:0000000000956714

Power steering pressure (PSP) sensor is installed to the power steering high-pressure tube and detects a
power steering load.
This sensor is a potentiometer which transforms the power steering load into output voltage, and emits the
voltage signal to the ECM. The ECM controls the electric throttle control actuator and adjusts the throttle valve
opening angle to increase the engine speed and adjusts the idle speed for the increased load.

DTC Logic

INFOID:0000000000956715

DTC DETECTION LOGIC

NOTE:
If DTC P0550 is displayed with DTC P0643, first perform the trouble diagnosis for DTC P0643. Refer to

EC-340, "DTC Logic"

.

DTC CONFIRMATION PROCEDURE

1.

PRECONDITIONING

If DTC Confirmation Procedure has been previously conducted, always turn ignition switch OFF and wait at
least 10 seconds before conducting the next test.

>> GO TO 2.

2.

PERFORM DTC CONFIRMATION PROCEDURE

1.

Start engine and let it idle for at least 5 seconds.

2.

Check 1st trip DTC.

Is 1st trip DTC detected?

YES

>> Go to 

EC-334, "Diagnosis Procedure"

.

NO

>> INSPECTION END

Diagnosis Procedure

INFOID:0000000000956716

1.

CHECK GROUND CONNECTION

1.

Turn ignition switch OFF.

2.

Check ground connection M95. Refer to Ground Inspection in 

GI-42, "Circuit Inspection"

.

Is the inspection result normal?

YES

>> GO TO 2.

NO

>> Repair or replace ground connection.

2.

CHECK PSP SENSOR POWER SUPPLY CIRCUIT

1.

Disconnect power steering pressure (PSP) sensor harness connector.

2.

Turn ignition switch ON.

3.

Check the voltage between PSP sensor harness connector and ground.

Is the inspection result normal?

YES

>> GO TO 3.

NO

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

DTC No.

Trouble diagnosis name

DTC detecting condition

Possible cause

P0550

Power steering pressure 
sensor circuit

An excessively low or high voltage from the 
sensor is sent to ECM.

• Harness or connectors

(The sensor circuit is open or shorted)

• Power steering pressure sensor

PSP sensor

Ground

Voltage

Connector

Terminal

F35

3

Ground

Approx. 5V

P0550 PSP SENSOR

EC-335

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3.

CHECK PSP SENSOR GROUND CIRCUIT FOR OPEN AND SHORT

1.

Turn ignition switch OFF.

2.

Disconnect ECM harness connector.

3.

Check the continuity between PSP sensor harness connector and ECM harness connector.

4.

Also check harness for short to ground and short to power.

Is the inspection result normal?

YES

>> GO TO 4.

NO

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

4.

CHECK PSP SENSOR INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT

1.

Check the continuity between PSP sensor harness connector and ECM harness connector.

2.

Also check harness for short to ground and short to power.

Is the inspection result normal?

YES

>> GO TO 5.

NO

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

5.

CHECK PSP SENSOR

Refer to 

EC-335, "Component Inspection"

.

Is the inspection result normal?

YES

>> GO TO 6.

NO

>> Replace PSP sensor.

6.

CHECK INTERMITTENT INCIDENT

Refer to 

GI-39, "Intermittent Incident"

.

>> INSPECTION END

Component Inspection

INFOID:0000000000956717

1.

CHECK POWER STEERING PRESSURE SENSOR

1.

Turn ignition switch OFF.

2.

Reconnect all harness connectors disconnected.

3.

Start engine and let it idle.

4.

Check the voltage between ECM harness connector and ground under the following conditions.

Is the inspection result normal?

YES

>> INSPECTION END

NO

>> Replace power steering pressure sensor.

PSP sensor

ECM

Continuity

Connector

Terminal

Connector

Terminal

F35

1

F102

96

Existed

PSP sensor

ECM

Continuity

Connector

Terminal

Connector

Terminal

F35

2

F102

87

Existed

ECM

Ground

Condition

Voltage

Connector

Terminal

F102

87

Ground

Steering wheel

Being turned

0.5 - 4.5V

Not being turned

0.4 - 0.8V

EC-336

< COMPONENT DIAGNOSIS >

[VQ35HR]

P0603 ECM POWER SUPPLY

P0603 ECM POWER SUPPLY

Description

INFOID:0000000000956718

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:0000000000956719

DTC DETECTION LOGIC

DTC CONFIRMATION PROCEDURE

1.

PRECONDITIONING

If DTC Confirmation Procedure has been previously conducted, always turn ignition switch OFF and wait at
least 10 seconds before conducting the next test.

>> 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-336, "Diagnosis Procedure"

.

NO

>> INSPECTION END

Diagnosis Procedure

INFOID:0000000000956720

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.

Is the inspection result normal?

YES

>> GO TO 3.

NO

>> GO TO 2.

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-337

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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-39, "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-336, "DTC Logic"

.

 With GST

1.

Turn ignition switch ON.

2.

Select Service $04 with GST.

3.

Perform DTC Confirmation Procedure.
See 

EC-336, "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-15, "ADDITIONAL SERVICE WHEN REPLACING CONTROL UNIT : Special Repair Require-

ment"

.

>> INSPECTION END