Nissan Frontier. Manual - part 443

P0550 PSP SENSOR

EC-343

< DTC/CIRCUIT DIAGNOSIS >

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NG

>> Repair or replace ground connections.

2.

CHECK PSP SENSOR POWER SUPPLY CIRCUIT

1. Disconnect power steering pressure (PSP) sensor harness con-

nector. 

2. Turn ignition switch ON.

3. Check voltage between PSP sensor terminal 3 and ground with

CONSULT or tester.

OK or NG

OK

>> GO TO 3.

NG

>> Repair open circuit, short to ground or short to power in

harness or connectors.

3.

CHECK PSP SENSOR GROUND CIRCUIT FOR OPEN AND SHORT

1. Turn ignition switch OFF.

2. Disconnect ECM harness connector.

3. Check harness continuity between PSP sensor terminal 1 and ECM terminal 48.

Refer to Wiring Diagram.

4. Also check harness for short to ground and short to power.
OK or NG

OK

>> GO TO 4.

NG

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

4.

CHECK PSP SENSOR INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT

1. Check harness continuity between ECM terminal 41 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 5.

NG

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

5.

CHECK PSP SENSOR

Refer to 

EC-344, "Component Inspection"

.

OK or NG

OK

>> GO TO 6.

NG

>> Replace PSP sensor. Refer to 

ST-20, "Removal and Installation"

.

6.

CHECK INTERMITTENT INCIDENT

Refer to 

GI-42, "Intermittent Incident"

.

BBIA0621E

Voltage: Approximately 5V

SEF479Y

Continuity should exist.

Continuity should exist.

EC-344

< DTC/CIRCUIT DIAGNOSIS >

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P0550 PSP SENSOR

>> INSPECTION END

Component Inspection

INFOID:0000000009481019

POWER STEERING PRESSURE SENSOR

1. Reconnect all harness connectors disconnected.
2. Start engine and let it idle.
3. Check voltage between ECM terminal 41 and ground under the following conditions.

Condition

Voltage

Steering wheel: Being turned

0.5 - 4.0V

Steering wheel: Not being turned

0.4 - 0.8V

P0603 ECM POWER SUPPLY

EC-345

< DTC/CIRCUIT DIAGNOSIS >

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P0603 ECM POWER SUPPLY

Component Description

INFOID:0000000009481020

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

INFOID:0000000009481021

DTC Confirmation Procedure

INFOID:0000000009481022

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.
1. If DTC Confirmation Procedure has been previously conducted, always perform the following procedure

before conducting the next step.

a. Turn ignition switch OFF and wait at least 10 seconds.
b. Turn ignition switch ON.
c. Turn ignition switch OFF and wait at least 10 seconds.
2. Turn ignition switch ON, wait at least 10 seconds.
3. Turn ignition switch OFF, wait at least 5 minutes.
4. Turn ignition switch ON, wait at least 10 seconds.
5. Repeat steps 2 to 3 for 5 times.
6. Check 1st trip DTC.
7. If 1st trip DTC is detected, go to 

EC-345, "Diagnosis Procedure"

.

Diagnosis Procedure

INFOID:0000000009481023

1.

CHECK ECM POWER SUPPLY

1. Turn ignition switch OFF.

2. Disconnect ECM harness connector.

3. Check voltage between ECM terminal 77 and ground with CONSULT or tester.

OK or NG

OK

>> GO TO 3.

NG

>> GO TO 2.

2.

DETECT MALFUNCTIONING PART

Check the following.

• 20A fuse (No.53)

PBIA9222J

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

Voltage: Battery voltage

EC-346

< DTC/CIRCUIT DIAGNOSIS >

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P0603 ECM POWER SUPPLY

• IPDM E/R harness connector E121

• Harness connectors E2, F32 

• Harness for open or short between ECM and battery

>> Repair or replace harness or connectors.

3.

CHECK INTERMITTENT INCIDENT

Refer to 

GI-42, "Intermittent Incident"

.

OK or NG

OK

>> GO TO 4.

NG

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

4.

PERFORM DTC CONFIRMATION PROCEDURE

With CONSULT

1. Turn ignition switch ON.

2. Select “SELF DIAG RESULTS” mode with CONSULT.

3. Touch “ERASE”.

4. Perform DTC Confirmation Procedure.

See 

EC-345, "DTC Confirmation Procedure"

.

5. Is the 1st trip DTC P0603 displayed again?

With GST

1. Turn ignition switch ON.

2. Select Service $04 with GST.

3. Perform “DTC Confirmation Procedure”.

See 

EC-345, "DTC Confirmation Procedure"

.

4. Is the 1st trip DTC P0603 displayed again?
Yes or No

Yes

>> GO TO 5.

No

>> INSPECTION END

5.

REPLACE ECM

CAUTION:

Perform PROCEDURE AFTER REPLACING ECM. Refer to 

EC-121, "Procedure After Replacing ECM"

.

Replace ECM.

>> INSPECTION END