Infiniti QX56 (JA60). Manual - part 407

EC-280

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P0507 ISC SYSTEM

3.

REPLACE ECM

1. Stop engine.

2. Replace ECM.

3. Perform initialization of IVIS(NATS) system and registration of all IVIS(NATS) ignition key IDs. Refer to

SEC-9, "ECM RE-COMMUNICATING FUNCTION : Special Repair Requirement"

.

4. Perform 

EC-17, "VIN Registration"

.

5. Perform 

EC-18, "Accelerator Pedal Released Position Learning"

.

6. Perform 

EC-18, "Throttle Valve Closed Position Learning"

.

7. Perform 

EC-18, "Idle Air Volume Learning"

.

>> INSPECTION END

P0550 PSP SENSOR

EC-281

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P0550 PSP SENSOR

Component Description

INFOID:0000000005149311

Power steering pressure (PSP) sensor (1) 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.

On Board Diagnosis Logic

INFOID:0000000005149312

The MIL will not light up for this self-diagnosis.

NOTE:

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

EC-289

.

DTC Confirmation Procedure

INFOID:0000000005149313

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. Start engine and let it idle for at least 5 seconds.
3. Check 1st trip DTC.
4. If 1st trip DTC is detected, go to 

EC-281, "Diagnosis Procedure"

.

Diagnosis Procedure

INFOID:0000000005149314

1.

CHECK GROUND CONNECTIONS

1. Turn ignition switch OFF.

2. Loosen and retighten three ground screws on the body.

Refer to 

EC-85, "Ground Inspection"

.

OK or NG

OK

>> GO TO 2.

NG

>> Repair or replace ground connections.

BBIA0741E

DTC No.

Trouble diagnosis name

DTC detecting condition

Possible cause

P0550
0550

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

BBIA0354E

EC-282

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P0550 PSP SENSOR

2.

CHECK PSP SENSOR POWER SUPPLY CIRCUIT

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

connector.

2. Turn ignition switch ON.

3. Check voltage between PSP sensor terminal 1 and ground with

CONSULT-III or tester.

OK or NG

OK

>> GO TO 3.

NG

>> Repair 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 3 and ECM terminal 67.

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 or 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 12 and PSP sensor terminal 2.

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

OK

>> GO TO 5.

NG

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

5.

CHECK PSP SENSOR

Refer to 

EC-283, "Component Inspection"

.

OK or NG

OK

>> GO TO 6.

NG

>> Replace PSP sensor.

6.

CHECK INTERMITTENT INCIDENT

Refer to 

GI-35, "How to Check Terminal"

 and 

GI-38, "Intermittent Incident"

.

>> INSPECTION END

BBIA0741E

Voltage: Approximately 5V

PBIB0188E

Continuity should exist.

Continuity should exist.

P0550 PSP SENSOR

EC-283

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Component Inspection

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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.

Condition

Voltage

Steering wheel: Being turned.

0.5 - 4.5 V

Steering wheel: Not being turned.

0.4 - 0.8 V

MBIB0126E