Page 229 of 720

DTC P0122, P0123, P0227, P0228 TP SENSOR
EC-229
C
D
E
F
G
H
I
J
K
L
MA
EC
Revision: 2006 November2007 350Z
DTC P0122, P0123, P0227, P0228 TP SENSORPFP:16119
Component DescriptionNBS0005U
Electric throttle control actuator consists of throttle control motor,
throttle position sensor, etc. The throttle position sensor responds to
the throttle valve movement.
The throttle position sensor has two sensors. These sensors are a
kind of potentiometers which transform the throttle valve position into
output voltage, and emit the voltage signal to the ECM. In addition,
these sensors detect the opening and closing speed of the throttle
valve and feed the voltage signals to the ECM. The ECM judges the
current opening angle of the throttle valve from these signals and the
ECM controls the throttle control motor to make the throttle valve
opening angle properly in response to driving condition.
CONSULT-III Reference Value in Data Monitor ModeNBS0005V
Specification data are reference values.
*: Throttle position sensor 2 signal is converted by ECM internally. Thus, it differs from ECM terminal voltage signal.
On Board Diagnosis LogicNBS0005W
These self-diagnoses have the one trip detection logic.
NOTE:
If DTC P0122, P0123, P0227 or P0228 is displayed with DTC P0643, first perform the trouble diagnosis
for DTC P0643.
Refer to EC-514, "
DTC P0643 SENSOR POWER SUPPLY" .
FAIL-SAFE MODE
When the malfunction is detected, ECM enters fail-safe mode and the MIL lights up.
PBIB0145E
MONITOR ITEM CONDITION SPECIFICATION
TP SEN 1-B1
TP SEN 1-B2
TP SEN 2-B1*
TP SEN 2-B2*
Ignition switch: ON
(Engine stopped)
Shift lever: D (A/T), 1st (M/T)Accelerator pedal: Fully released More than 0.36V
Accelerator pedal: Fully depressed Less than 4.75V
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0122
0122
(Bank 1)
Throttle position sensor
2 circuit low inputAn excessively low voltage from the TP sensor
2 is sent to ECM.
Harness or connectors
(TP sensor 2 circuit is open or shorted.)
Electric throttle control actuator
(TP sensor 2) P0227
0227
(Bank 2)
P0123
0123
(Bank 1)
Throttle position sensor
2 circuit high inputAn excessively high voltage from the TP sen-
sor 2 is sent to ECM.
P0228
0228
(Bank 2)
Engine operation condition in fail-safe mode
The ECM controls the electric throttle control actuator in regulating the throttle opening in order for the idle position to be within +10
degrees.
The ECM regulates the opening speed of the throttle valve to be slower than the normal condition.
So, the acceleration will be poor.
Page 230 of 720
EC-230
DTC P0122, P0123, P0227, P0228 TP SENSOR
Revision: 2006 November2007 350Z
DTC Confirmation ProcedureNBS0005X
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 8V at idle.
WITH CONSULT-III
1. Start engine and let it idle for 1 second.
2. Check DTC.
3. If DTC is detected, go to EC-235, "
Diagnostic Procedure" .
WITH GST
Follow the procedure “WITH CONSULT-III” above.
Page 232 of 720

EC-232
DTC P0122, P0123, P0227, P0228 TP SENSOR
Revision: 2006 November2007 350Z
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.
TER-
MINAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
30 YThrottle position sensor 1
(bank 1)[Ignition switch: ON]
Engine stopped
Shift lever: D (A/T) or 1st (M/T)
Accelerator pedal: Fully releasedMore than 0.36V
[Ignition switch: ON]
Engine stopped
Shift lever: D (A/T) or 1st (M/T)
Accelerator pedal: Fully depressedLess than 4.75V
34 LThrottle position sensor 2
(bank 1)[Ignition switch: ON]
Engine stopped
Shift lever: D (A/T) or 1st (M/T)
Accelerator pedal: Fully releasedLess than 4.75V
[Ignition switch: ON]
Engine stopped
Shift lever: D (A/T) or 1st (M/T)
Accelerator pedal: Fully depressedMore than 0.36V
40 RSensor ground
[Throttle position sensor
(bank 1)][Engine is running]
Warm-up condition
Idle speed0V
44 BSensor power supply
[Throttle position sensor
(bank 1)][Ignition switch: ON]5V
Page 234 of 720

EC-234
DTC P0122, P0123, P0227, P0228 TP SENSOR
Revision: 2006 November2007 350Z
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.
TER-
MINAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
31 L/GThrottle position sensor 1
(bank 2)[Ignition switch: ON]
Engine stopped
Shift lever: D (A/T) or 1st (M/T)
Accelerator pedal: Fully releasedMore than 0.36V
[Ignition switch: ON]
Engine stopped
Shift lever: D (A/T) or 1st (M/T)
Accelerator pedal: Fully depressedLess than 4.75V
35 L/YThrottle position sensor 2
(bank 2)[Ignition switch: ON]
Engine stopped
Shift lever: D (A/T) or 1st (M/T)
Accelerator pedal: Fully releasedLess than 4.75V
[Ignition switch: ON]
Engine stopped
Shift lever: D (A/T) or 1st (M/T)
Accelerator pedal: Fully depressedMore than 0.36V
43 OR/LSensor power supply
[Throttle position sensor
(bank 2)][Ignition switch: ON]5V
48 W/LSensor ground
[Throttle position sensor
(bank 2)][Engine is running]
Warm-up condition
Idle speed0V
Page 239 of 720

DTC P0125 ECT SENSOR
EC-239
C
D
E
F
G
H
I
J
K
L
MA
EC
Revision: 2006 November2007 350Z
DTC P0125 ECT SENSORPFP:22630
Component DescriptionNBS00062
The engine coolant temperature sensor is used to detect the engine
coolant temperature. The sensor modifies a voltage signal from the
ECM. The modified signal returns to the ECM as the engine coolant
temperature input. The sensor uses a thermistor which is sensitive to
the change in temperature. The electrical resistance of the ther-
mistor decreases as temperature increases.
*: This data is reference values and is measured between ECM terminal 71 (Engine
coolant temperature sensor) 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.
On Board Diagnosis LogicNBS00063
NOTE:
If DTC P0125 is displayed with P0117 or P0118, first perform the trouble diagnosis for DTC P0117 or
P0118.
Refer to EC-223, "
DTC P0117, P0118 ECT SENSOR" .
SEF594K
Engine coolant
temperature°C (°F)Voltage* V Resistance kΩ
−10 (14) 4.4 7.0 - 11.4
20 (68) 3.5 2.37 - 2.63
50 (122) 2.2 0.68 - 1.00
90 (194) 0.9 0.236 - 0.260
SEF012P
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0125
0125Insufficient engine cool-
ant temperature for
closed loop fuel control
Voltage sent to ECM from the sensor is not
practical, even when some time has passed
after starting the engine.
Engine coolant temperature is insufficient for
closed loop fuel control.
Harness or connectors
(High resistance in the circuit)
Engine coolant temperature sensor
Thermostat
Page 240 of 720
EC-240
DTC P0125 ECT SENSOR
Revision: 2006 November2007 350Z
DTC Confirmation ProcedureNBS00064
CAUTION:
Be careful not to overheat engine.
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. Turn ignition switch ON.
2. Select “DATA MONITOR” mode with CONSULT-III.
3. Check that “COOLAN TEMP/S” is above 10°C (50°F).
If it is above 10°C (50°F), the test result will be OK.
If it is below 10°C (50°F), go to following step.
4. Start engine and run it for 65 minutes at idle speed.
If “COOLAN TEMP/S” increases to more than 10°C (50°F) within 65 minutes, stop engine because
the test result will be OK.
5. Check 1st trip DTC.
6. If 1st trip DTC is detected, go to EC-241, "
Diagnostic Procedure" .
WITH GST
Follow the procedure “WITH CONSULT-III” above.
Page 241 of 720
DTC P0125 ECT SENSOR
EC-241
C
D
E
F
G
H
I
J
K
L
MA
EC
Revision: 2006 November2007 350Z
Diagnostic ProcedureNBS00065
1. CHECK GROUND CONNECTIONS
Models with VDC system, navigation system or telephone
1. Turn ignition switch OFF.
2. Loosen and retighten ground screws on the body. Refer to EC-150, "
Ground Inspection" .
Models without VDC system, navigation system and telephone
1. Turn ignition switch OFF.
2. Loosen and retighten ground screws on the body. Refer to EC-150, "
Ground Inspection" .
OK or NG
OK >> GO TO 2.
NG >> Repair or replace ground connections.
2. CHECK ENGINE COOLANT TEMPERATURE SENSOR
Refer to EC-242, "
Component Inspection" .
OK or NG
OK >> GO TO 3.
NG >> Replace engine coolant temperature sensor.
1. Body ground E17 2. Body ground E43 3. Body ground B102
:Vehicle front
1. Body ground E17 2. Body ground E43 3. Body ground F152
(Passenger side view with dash side
finisher removed)
:Vehicle front
PBIB3560E
PBIB3561E
Page 242 of 720
EC-242
DTC P0125 ECT SENSOR
Revision: 2006 November2007 350Z
3. CHECK THERMOSTAT OPERATION
When the engine is cold [lower than 70°C (158°F)] condition, grasp lower radiator hose and confirm the engine
coolant does not flow.
OK or NG
OK >> GO TO 4.
NG >> Repair or replace thermostat. Refer to CO-26, "
WATER INLET AND THERMOSTAT ASSEMBLY"
.
4. CHECK INTERMITTENT INCIDENT
Refer to EC-141, "
TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT" .
Refer to EC-225, "
Wiring Diagram" .
>>INSPECTION END
Component InspectionNBS00066
ENGINE COOLANT TEMPERATURE SENSOR
1. Check resistance between engine coolant temperature sensor
terminals 1 and 2 as shown in the figure.
2. If NG, replace engine coolant temperature sensor.
Removal and InstallationNBS00067
ENGINE COOLANT TEMPERATURE SENSOR
Refer to CO-28, "WATER OUTLET AND WATER PIPING" .
PBIB2005E
Engine coolant
temperature°C (°F)Resistance kΩ
20 (68) 2.37 - 2.63
50 (122) 0.68 - 1.00
90 (194) 0.236 - 0.260
SEF012P