2004 INFINITI FX35 steering

EC-1052
[VK45DE]
DTC P0550 PSP SENSOR
Revision: 2004 November 2004 FX35/FX45
DTC P0550 PSP SENSORPFP:49763
Component DescriptionABS00C7N
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.
CONSULT-II Reference Value in Data Monitor ModeABS00C7O
Specification data are reference values.
On Board Diagnosis LogicABS00C7P
The MIL will not light up for this diagnosis.
NOTE:
If DTC P0550 is displayed with DTC P1229, first perform the trouble diagnosis for DTC P1229. Refer to
EC-1156
.
DTC Confirmation ProcedureABS00C7Q
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.
2. Select “DATA MONITOR” mode with CONSULT-II.
3. Start engine and let it idle for at least 5 seconds.
4. If 1st trip DTC is detected, go to EC-1054, "
Diagnostic Proce-
dure" .
WITH GST
Follow the procedure “WITH CONSULT-II” above.
PBIB1484E
MONITOR ITEM CONDITION SPECIFICATION
PW/ST SIGNAL

Engine: After warming up, idle
the engineSteering wheel is in neutral position
(Forward direction)OFF
Steering wheel is turned ON
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0550
0550Power steering pres-
sure sensor circuitAn 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
SEF058Y

EC-1054
[VK45DE]
DTC P0550 PSP SENSOR
Revision: 2004 November 2004 FX35/FX45
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 ProcedureABS00C7S
1. CHECK GROUND CONNECTIONS
1. Turn ignition switch OFF.
2. Loosen and retighten three ground screws on the body.
Refer to EC-791, "
Ground Inspection" .
OK or NG
OK >> GO TO 2.
NG >> Repair or replace ground connections.
TER-
MINAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
12 R/GPower steering pressure
sensor[Engine is running]

Steering wheel is being turned0.5 - 4.5V
[Engine is running]

Steering wheel is not being turned0.4 - 0.8V
67 B/WSensor ground
(Mass air flow sensor / IAT
sensor / Power steering
pressure sensor / EVAP
control system pressure
sensor / Refrigerant pres-
sure sensor / ECT sensor)[Engine is running]

Warm-up condition

Idle speedApproximately 0V
68 SBSensor power supply
(Power steering pressure
sensor)[Ignition switch: ON]Approximately 5V
PBIB2195E

DTC P0550 PSP SENSOR
EC-1055
[VK45DE]
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Revision: 2004 November 2004 FX35/FX45
2. CHECK PSP SENSOR POWER SUPPLY CIRCUIT
1. Disconnect PSP sensor harness connector.
2. Turn ignition switch ON.
3. Check voltage between PSP sensor terminal 1 and ground with
CONSULT-II or tester.
OK or NG
OK >> GO TO 4.
NG >> GO TO 3.
3. DETECT MALFUNCTIONING PART
Check the following.

Harness connectors E306, F46

Harness for open or short between power steering pressure sensor and ECM
>> Repair open circuit or short to power in harness or connectors.
4. 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 6.
NG >> GO TO 5.
5. DETECT MALFUNCTIONING PART
Check the following.

Harness connectors E306, F46

Harness for open or short between power steering pressure sensor and ECM
>> Repair open circuit or short to ground short to power in harness or connectors.
PBIB1484E
Voltage: Approximately 5V
PBIB0188E
Continuity should exist.

EC-1056
[VK45DE]
DTC P0550 PSP SENSOR
Revision: 2004 November 2004 FX35/FX45
6. 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 8.
NG >> GO TO 7.
7. DETECT MALFUNCTIONING PART
Check the following.

Harness connectors E306, F46

Harness for open or short between power steering pressure sensor and ECM
>> Repair open circuit or short to power in harness or connectors.
8. CHECK PSP SENSOR
Refer to EC-1056, "
Component Inspection" .
OK or NG
OK >> GO TO 9.
NG >> Replace PSP sensor.
9. CHECK INTERMITTENT INCIDENT
Refer to EC-784, "
TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT" .
>>INSPECTION END
Component InspectionABS00C7T
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 InstallationABS00C7U
POWER STEERING PRESSURE SENSOR
Refer to PS-41, "HYDRAULIC LINE" . Continuity should exist.
Condition Voltage
Steering wheel is being turned. 0.5 - 4.5V
Steering wheel is not being turned. 0.4 - 0.8V
MBIB0126E

DTC P1102 MAF SENSOR
EC-1067
[VK45DE]
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Revision: 2004 November 2004 FX35/FX45
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 ProcedureABS00C89
1. CHECK GROUND CONNECTIONS
1. Turn ignition switch OFF.
2. Loosen and retighten three ground screws on the body.
Refer to EC-791, "
Ground Inspection" .
OK or NG
OK >> GO TO 2.
NG >> Repair or replace ground connections.
TER-
MINAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
48 LSensor power supply
(Mass air flow sensor)[Ignition switch: ON]Approximately 5V
51 L/W Mass air flow sensor[Engine is running]

Warm-up condition

Idle speed1.2 - 1.8V
[Engine is running]

Warm-up condition

Engine speed is 2,500 rpm1.7 - 2.4V
67 B/WSensor ground
(Mass air flow sensor / IAT
sensor / Power steering
pressure sensor / EVAP
control system pressure
sensor / Refrigerant pres-
sure sensor / ECT sensor)[Engine is running]

Warm-up condition

Idle speedApproximately 0V
111 W / BECM relay
(Self shut-off)[Engine is running]
[Ignition switch: OFF]

For a few seconds after turning ignition
switch OFF0 - 1.5V
[Ignition switch: OFF]

More than a few seconds after turning igni-
tion switch OFFBATTERY VOLTAGE
(11 - 14V)
11 9
120R
RPower supply for ECM[Ignition switch: ON]BATTERY VOLTAGE
(11 - 14V)
PBIB2195E

EC-1156
[VK45DE]
DTC P1229 SENSOR POWER SUPPLY
Revision: 2004 November 2004 FX35/FX45
DTC P1229 SENSOR POWER SUPPLYPFP:16119
On Board Diagnosis LogicABS00CB8
This self-diagnosis has the one trip detection logic.
FAIL-SAFE MODE
When the malfunction is detected, ECM enters fail-safe mode and the MIL lights up.
DTC Confirmation ProcedureABS00CB9
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.
TESTING CONDITION:
Before performing the following procedure, confirm that battery voltage is more than 10V at idle.
WITH CONSULT-II
1. Turn ignition switch ON.
2. Select “DATA MONITOR” mode with CONSULT-II.
3. Start engine and let it idle for 1 second.
4. If DTC is detected, go to EC-1158, "
Diagnostic Procedure" .
WITH GST
Follow the procedure “WITH CONSULT-II” above.
DTC No.Trouble diagnosis
nameDTC detecting condition Possible cause
P1229
1229Sensor power supply
circuit shortECM detects a voltage of power source for
sensor is excessively low or high.

Harness or connectors
(APP sensor 1 circuit is shorted.)
(Mass air flow sensor is shorted.)
(EVAP control system pressure sensor is
shorted.)
(Refrigerant pressure sensor circuit is
shorted.)
(PSP sensor circuit is shorted.)

Accelerator pedal position sensor

Mass air flow sensor

EVAP control system pressure sensor

Refrigerant pressure sensor

Power steering pressure sensor
Engine operation condition in fail-safe mode
ECM stops the electric throttle control actuator control, throttle valve is maintained at a fixed opening (approx. 5 degrees) by the return
spring.
SEF058Y

EC-1158
[VK45DE]
DTC P1229 SENSOR POWER SUPPLY
Revision: 2004 November 2004 FX35/FX45
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 ProcedureABS00CBB
1. CHECK GROUND CONNECTIONS
1. Turn ignition switch OFF.
2. Loosen and retighten three ground screws on the body.
Refer to EC-791, "
Ground Inspection" .
OK or NG
OK >> GO TO 2.
NG >> Repair or replace ground connections.
2. CHECK ACCELERATOR PEDAL POSITION SENSOR 1 POWER SUPPLY CIRCUIT
1. Disconnect accelerator pedal position (APP) sensor harness connector.
2. Turn ignition switch ON.
3. Check voltage between APP sensor terminal 6 and ground with
CONSULT-II or tester.
OK or NG
OK >> GO TO 5.
NG >> GO TO 3.
TER-
MINAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
48 LSensor power supply
(Mass air flow sensor /
EVAP control system pres-
sure sensor)[Ignition switch: ON]Approximately 5V
49 PUSensor power supply
(Refrigerant pressure sen-
sor)[Ignition switch: ON]Approximately 5V
68 SBSensor power supply
(Power steering pressure
sensor)[Ignition switch: ON]Approximately 5V
90 L/BSensor power supply
(APP sensor 1)[Ignition switch: ON]Approximately 5V
PBIB2195E
Voltage: Approximately 5V
PBIB0914E

DTC P1229 SENSOR POWER SUPPLY
EC-1159
[VK45DE]
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Revision: 2004 November 2004 FX35/FX45
3. CHECK SESNRO POWER SUPPLY CIRCUITS
Check harness for short to power and short to ground, between the following terminals.
OK or NG
OK >> GO TO 4.
NG >> Repair short to ground or short to power in harness or connectors.
4. CHECK COMPONENTS
Check the following.

Mass air flow sensor (Refer to EC-829, "Component Inspection" .)

EVAP control pressure sensor (Refer to EC-1013, "Component Inspection" .)

Refrigerant pressure sensor (Refer to AT C - 9 0 , "COMPONENT INSPECTION" .)

Power steering pressure sensor (Refer to EC-1056, "Component Inspection" .)
OK or NG
OK >> GO TO 7.
NG >> Replace malfunctioning component.
5. CHECK APP SENSOR
Refer to EC-1230, "
Component Inspection" .
OK or NG
OK >> GO TO 7.
NG >> GO TO 6.
6. REPLACE ACCELERATOR PEDAL ASSEMBLY
1. Replace accelerator pedal assembly.
2. Perform EC-698, "
Accelerator Pedal Released Position Learning" .
3. Perform EC-698, "
Throttle Valve Closed Position Learning" .
4. Perform EC-698, "
Idle Air Volume Learning" .
>>INSPECTION END
7. CHECK INTERMITTENT INCIDENT
Refer to EC-784, "
TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT" .
>>INSPECTION END
ECM terminal Sensor terminal Reference Wiring Diagram
90 APP sensor terminal 6EC-1227
48 Mass air flow sensor terminal 2EC-825
48 EVAP control pressure sensor terminal 3EC-1009
49 Refrigerant pressure sensor terminal 1EC-1288
68 PSP sensor terminal 1EC-1053