Infiniti M35/M45 Y50. Manual - part 678

DTC P0550 PSP SENSOR

EC-1185

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6. 

CHECK PSP SENSOR INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT

1.

Check harness continuity between ECM terminal 12 and PSP sensor terminal 2.
Refer to Wiring Diagram.

2.

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

OK or NG

OK

>> GO TO 8.

NG

>> GO TO 7.

7. 

DETECT MALFUNCTIONING PART 

Check the following.

●

Harness connectors E206, E72

●

Harness connectors E11, F2

●

Harness for open or short between power steering pressure sensor and ECM

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

8. 

CHECK PSP SENSOR

Refer to 

EC-1185, "Component Inspection"

 .

OK or NG

OK

>> GO TO 9.

NG

>> Replace PSP sensor.

9. 

CHECK INTERMITTENT INCIDENT

Refer to 

EC-857, "TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT"

 .

>> INSPECTION END

Component Inspection

NBS005JN

POWER STEERING PRESSURE SENSOR

1.

Reconnect all harness connectors disconnected.

2.

Start engine and let it idle.

3.

Check voltage between ECM terminal 12 and ground under the
following conditions.

Removal and Installation

NBS005JO

POWER STEERING PRESSURE SENSOR

Refer to 

PS-39, "HYDRAULIC LINE"

 .

Continuity should exist.

Condition

Voltage

Steering wheel: Being turned.

0.5 - 4.5V

Steering wheel: Not being turned.

0.4 - 0.8V

MBIB0126E

EC-1186

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DTC P0603 ECM POWER SUPPLY

DTC P0603 ECM POWER SUPPLY

PFP:23710

Component Description

NBS005JP

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.

On Board Diagnosis Logic

NBS005JQ

DTC Confirmation Procedure

NBS005JR

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

 WITH CONSULT-II

1.

Turn ignition switch ON and wait at least 1 second.

2.

Select “DATA MONITOR” mode with CONSULT-II.

3.

Start engine and let it idle for 1 second.

4.

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

5.

Repeat steps 3 and 4 for four times.

6.

If 1st trip DTC is detected, go to 

EC-1188, "Diagnostic Proce-

dure"

 .

 WITH GST

Follow the procedure “WITH CONSULT-II” above.

PBIB1164E

DTC No.

Trouble diagnosis name

DTC detecting condition

Possible cause

P0603
0603

ECM power supply circuit

ECM back-up RAM system does not function 
properly.

●

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

●

ECM

SEF058Y

DTC P0603 ECM POWER SUPPLY

EC-1187

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Wiring Diagram

NBS005JS

TBWT1035E

EC-1188

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DTC P0603 ECM POWER SUPPLY

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

NBS005JT

1. 

CHECK ECM POWER SUPPLY

1.

Turn ignition switch OFF.

2.

Disconnect ECM harness connector.

3.

Check voltage between ECM terminal 121 and ground with
CONSULT-II or tester.

OK or NG

OK

>> GO TO 3.

NG

>> GO TO 2.

2. 

DETECT MALFUNCTIONING PART

Check the following.

●

Harness connectors E108, M15

●

20A fuse

●

IPDM E/R harness connector E8

●

Harness for open or short between ECM and battery

>> Repair or replace harness or connectors.

3. 

CHECK INTERMITTENT INCIDENT

Refer to 

EC-857, "TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT"

 .

OK or NG

OK

>> GO TO 4.

NG

>> Repair or replace harness or connectors.

TER-

MINAL 

NO.

WIRE 

COLOR

ITEM

CONDITION

DATA (DC Voltage)

121

L

Power supply for ECM 
(Back-up)

[Ignition switch: OFF]

BATTERY VOLTAGE
(11 - 14V)

Voltage: Battery voltage

MBIB0026E