Page 97 of 720
TROUBLE DIAGNOSIS
EC-97
C
D
E
F
G
H
I
J
K
L
MA
EC
Revision: 2006 November2007 350Z
1. Refrigerant pressure sensor har-
ness connector2. IPDM E/R
1. Power steering pressure sensor 2. Alternator 3. Engine oil temperature sensor
:Vehicle front
1. EVAP service port 2. EVAP canister purge volume con-
trol solenoid valve3. EVAP canister vent control valve
4. EVAP control system pressure sen-
sor5. EVAP canister
:Vehicle front
PBIB3510E
PBIB3522E
PBIB3475E
PBIB3495E
Page 138 of 720

EC-138
TROUBLE DIAGNOSIS - SPECIFICATION VALUE
Revision: 2006 November2007 350Z
17. CHECK “B/FUEL SCHDL”
Select “B/FUEL SCHDL” in “SPEC” of "DATA MONITOR" mode, and make sure that the indication is within the
SP value.
OK or NG
OK >>INSPECTION END
NG (More than the SP value)>>GO TO 18.
NG (Less than the SP value)>>GO TO 25.
18. DETECT MALFUNCTIONING PART
1. Check for the cause of large engine friction. Refer to the following.
–Engine oil level is too high
–Engine oil viscosity
–Belt tension of power steering, alternator, A/C compressor, etc. is excessive
–Noise from engine
–Noise from transmission, etc.
2. Check for the cause of insufficient combustion. Refer to the following.
–Valve clearance malfunction
–Intake valve timing control function malfunction
–Camshaft sprocket installation malfunction, etc.
>> Repair or replace malfunctioning part, and then GO TO 30.
19. CHECK INTAKE SYSTEM
Check for the cause of uneven air flow through mass air flow sensor. Refer to the following.
Crushed air ducts
Malfunctioning seal of air cleaner element
Uneven dirt of air cleaner element
Improper specification of intake air system
OK or NG
OK >> GO TO 21.
NG >> Repair or replace malfunctioning part, and then GO TO 20.
20. CHECK “A/F ALPHA-B1”, “A/F ALPHA-B2”, AND “B/FUEL SCHDL”
Select “A/F ALPHA-B1”, “A/F ALPHA-B2”, and “B/FUEL SCHDL” in “SPEC” of "DATA MONITOR" mode, and
make sure that the each indication is within the SP value.
OK or NG
OK >>INSPECTION END
NG (“B/FUEL SCHDL” is more, “A/F ALPHA-B1”, “A/F ALPHA-B2” are less than the SP value)>>GO TO 21.
21. DISCONNECT AND RECONNECT MASS AIR FLOW SENSOR HARNESS CONNECTOR
1. Stop the engine.
2. Disconnect mass air flow sensor harness connector. Check pin terminal and connector for damage and
then reconnect it again.
>> GO TO 22.
Page 502 of 720

EC-502
DTC P0550 PSP SENSOR
Revision: 2006 November2007 350Z
DTC P0550 PSP SENSORPFP:49763
Component DescriptionNBS000AU
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.
CONSULT-III Reference Value in Data Monitor ModeNBS000AV
Specification data are reference values.
On Board Diagnosis LogicNBS000AW
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-514, "
DTC P0643 SENSOR POWER SUPPLY" .
DTC Confirmation ProcedureNBS000AX
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-III
1. Start engine and let it idle for at least 5 seconds.
2. Check 1st trip DTC.
3. If 1st trip DTC is detected, go to EC-505, "
Diagnostic Procedure" .
WITH GST
Follow the procedure “WITH CONSULT-III” above.
2 : Alternator
: Vehicle front
PBIB3511E
MONITOR ITEM CONDITION SPECIFICATION
PW/ST SIGNAL
Engine: After warming up, idle
the engineSteering wheel: Not being turned OFF
Steering wheel: Being 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
Page 506 of 720

EC-506
DTC P0550 PSP SENSOR
Revision: 2006 November2007 350Z
2. CHECK PSP SENSOR POWER SUPPLY CIRCUIT
1. Disconnect power steering pressure (PNP) 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 open circuit or 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 3 and ECM terminal 96.
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 87 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 or short to ground or short to power in harness or connectors.
5. CHECK PSP SENSOR
Refer to EC-507, "
Component Inspection" .
OK or NG
OK >> GO TO 6.
NG >> Replace PNP sensor.
1 : Alternator
: Vehicle front
PBIB3511E
Voltage: Approximately 5V
PBIB0188E
Continuity should exist.
Continuity should exist.