2003 NISSAN TEANA light

TROUBLE DIAGNOSIS
EC-401
[VQ]
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Fail-Safe ChartBBS004Y8
When the DTC listed below is detected, the ECM enters fail-safe mode and the MI lights up.

When there is an open circuit on MI circuit, the ECM cannot warn the driver by lighting up MI when there
is malfunction on engine control system.
Therefore, when electrical controlled throttle and part of ECM related diagnoses are continuously detected
as NG for 5 trips, ECM warns the driver that engine control system malfunctions and MI circuit is open by
means of operating fail-safe function.
The fail-safe function also operates when above diagnoses except MI circuit are detected and demands
the driver to repair the malfunction.
DTC No. Detected items Engine operating condition in fail-safe mode
P0102
P0103Mass air flow sensor circuit Engine speed will not rise more than 2,400 rpm due to the fuel cut.
P0122
P0123
P0222
P0223
P2135Throttle position sensor 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.
P1121 Electric throttle control
actuator(When electric throttle control actuator does not function properly due to the return spring
malfunction:)
ECM controls the electric throttle actuator by regulating the throttle opening around the
idle position. The engine speed will not rise more than 2,000 rpm.
(When throttle valve opening angle in fail-safe mode is not in specified range:)
ECM controls the electric throttle control actuator by regulating the throttle opening to 20
degrees or less.
(When ECM detects the throttle valve is stuck open:)
While the vehicle is driving, it slows down gradually by fuel cut. After the vehicle stops,
the engine stalls.
The engine can restart in P or N position, and engine speed will not exceed 1,000 rpm or
more.
P1122 Electric throttle control
functionECM stops the electric throttle control actuator control, throttle valve is maintained at a
fixed opening (approx. 5 degrees) by the return spring.
P1124
P1126Throttle control motor relay ECM stops the electric throttle control actuator control, throttle valve is maintained at a
fixed opening (approx. 5 degrees) by the return spring.
P1128 Throttle control motor ECM stops the electric throttle control actuator control, throttle valve is maintained at a
fixed opening (approx. 5 degrees) by the return spring.
P1229 Sensor power supply ECM stops the electric throttle control actuator control, throttle valve is maintained at a
fixed opening (approx. 5 degrees) by the return spring.
P1805 Brake switch ECM controls the electric throttle control actuator by regulating the throttle opening to a
small range.
Therefore, acceleration will be poor.
Vehicle condition Driving condition
When engine is idling Normal
When accelerating Poor acceleration
P2122
P2123
P2127
P2128
P2138Accelerator pedal position
sensorThe 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.
Engine operating condition in fail-safe mode Engine speed will not rise more than 2,500 rpm due to the fuel cut

TROUBLE DIAGNOSIS
EC-423
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98 LGAccelerator pedal position
sensor 2[Ignition switch: ON]

Engine: Stopped

Accelerator pedal: Fully released0.28 - 0.48V
[Ignition switch: ON]

Engine: Stopped

Accelerator pedal: Fully depressedMore than 2.0V
99 G/Y ASCD steering switch[Ignition switch: ON]

ASCD steering switch: OFFApproximately 4V
[Ignition switch: ON]

MAIN switch: PressedApproximately 0V
[Ignition switch: ON]

CANCEL switch: PressedApproximately 1V
[Ignition switch: ON]

RESUME/ACCELERATE switch: PressedApproximately 3V
[Ignition switch: ON]

SET/COAST switch: PressedApproximately 2V
101 R/G Stop lamp switch[Ignition switch: OFF]

Brake pedal: Fully releasedApproximately 0V
[Ignition switch: OFF]

Brake pedal: Slightly depressedBATTERY VOLTAGE
(11 - 14V)
102 G/W PNP switch[Ignition switch: ON]

Shift lever: P or NApproximately 0V
[Ignition switch: ON]

Except aboveBATTERY VOLTAGE
(11 - 14V)
103 L/OR Tachometer signal output[Engine is running]

Warm-up condition

Idle speed
NOTE:
The pulse cycle changes depending on rpm
at idleApproximately 0.8V
[Engine is running]

Warm-up condition

Engine speed: 2,000 rpmApproximately 0.8V
104 P/L Throttle control motor relay[Ignition switch: OFF]BATTERY VOLTAGE
(11 - 14V)
[Ignition switch: ON]0 - 1.0V
106 WAccelerator pedal position
sensor 1[Ignition switch: ON]

Engine: Stopped

Accelerator pedal: Fully released0.65 - 0.87V
[Ignition switch: ON]

Engine: Stopped

Accelerator pedal: Fully depressedMore than 4.3V TER-
MINAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
MBIB0053E
MBIB0054E

EC-424
[VQ]
TROUBLE DIAGNOSIS

: Average voltage for pulse signal (Actual pulse signal can be confirmed by oscilloscope.)108 G/R ASCD brake switch[Ignition switch: ON]

Brake pedal: Slightly depressedApproximately 0V
[Ignition switch: ON]

Brake pedal: Fully releasedBATTERY VOLTAGE
(11 - 14V)
109 R Ignition switch[Ignition switch: OFF]0V
[Ignition switch: ON]BATTERY VOLTAGE
(11 - 14V)
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)
113 B/R Fuel pump relay[Ignition switch: ON]

For 1 second after turning ignition switch
ON
[Engine is running]0 - 1.5V
[Ignition switch: ON]

More than 1 second after turning ignition
switch ONBATTERY VOLTAGE
(11 - 14V)
11 5
11 6B
BECM ground[Engine is running]

Idle speedBody ground
11 9
120R/G
R/GPower supply for ECM[Ignition switch: ON]BATTERY VOLTAGE
(11 - 14V)
121 W/LPower supply for ECM
(Back-up)[Ignition switch: OFF]BATTERY VOLTAGE
(11 - 14V) TER-
MINAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)

TROUBLE DIAGNOSIS
EC-429
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START SIGNAL
[ON/OFF]××
Indicates start signal status [ON/OFF] com-
puted by the ECM according to the signals
of engine speed and battery voltage.
After starting the engine, [OFF] is
displayed regardless of the starter
signal.
CLSD THL POS
[ON/OFF]××

Indicates idle position [ON/OFF] computed
by ECM according to the accelerator pedal
position sensor signal.
AIR COND SIG
[ON/OFF]××

Indicates [ON/OFF] condition of the air
conditioner switch as determined by the air
conditioner signal.
P/N POSI SW
[ON/OFF]××

Indicates [ON/OFF] condition from the
park/neutral position (PNP) switch signal.
PW/ST SIGNAL
[ON/OFF]××

[ON/OFF] condition of the power steering
system (determined by the signal voltage
of the power steering pressure sensor sig-
nal) is indicated.
LOAD SIGNAL
[ON/OFF]××

Indicates [ON/OFF] condition from the
electrical load signal.
ON: Rear window defogger switch is ON
and/or lighting switch is in 2nd position.
OFF: Both rear window defogger switch
and lighting switch are OFF.
IGNITION SW
[ON/OFF]×

Indicates [ON/OFF] condition from ignition
switch signal.
HEATER FAN SW
[ON/OFF]×

Indicates [ON/OFF] condition from heater
fan switch signal.
BRAKE SW
[ON/OFF]×

Indicates [ON/OFF] condition from the stop
lamp switch signal.
INJ PULSE-B1
[msec]×

Indicates the actual fuel injection pulse
width compensated by ECM according to
the input signals.
When the engine is stopped, a cer-
tain computed value is indicated.
INJ PULSE-B2
[msec]
IGN TIMING
[BTDC]×

Indicates the ignition timing computed by
ECM according to the input signals.
When the engine is stopped, a cer-
tain value is indicated.
PURG VOL C/V
[%]

Indicates the EVAP canister purge volume
control solenoid valve control value com-
puted by the ECM according to the input
signals.

The opening becomes larger as the value
increases.
INT/V TIM (B1)
[°CA]

Indicates [°CA] of intake camshaft
advanced angle.
INT/V TIM (B2)
[°CA]
INT/V SOL (B1) [%]

The control condition of the intake valve
timing control solenoid valve (determined
by ECM according to the input signals) is
indicated.

The advance angle becomes larger as the
value increases. INT/V SOL (B2) [%]Monitored item
[Unit]ECM
INPUT
SIGNALSMAIN
SIGNALSDescription Remarks

EC-432
[VQ]
TROUBLE DIAGNOSIS

DATA MONITOR (SPEC) MODE
Monitored Item
NOTE:
Any monitored item that does not match the vehicle being diagnosed is deleted from the display automatically.
ACTIVE TEST MODE
Test Item
Monitored item [Unit]ECM
INPUT
SIG-
NALSMAIN
SIG-
NALSDescription Remarks
ENG SPEED [rpm]××

Indicates the engine speed computed
from the signal of the crankshaft position
sensor (POS) and camshaft position
sensor (PHASE).
MAS A/F SE-B1 [V]××

The signal voltage of the mass air flow
sensor specification is displayed.
When engine is running specification
range is indicated.
B/FUEL SCHDL
[msec]×

Base fuel schedule indicates the fuel
injection pulse width programmed into
ECM, prior to any learned on board cor-
rection.

When engine is running specification
range is indicated.
A/F ALPHA-B1 [%]
A/F ALPHA-B2 [%]×

The mean value of the air-fuel ratio feed-
back correction factor per cycle is indi-
cated.
When engine is running specification
range is indicated.

This data also includes the data for the
air-fuel ratio learning control.
TEST ITEM CONDITION JUDGEMENT CHECK ITEM (REMEDY)
FUEL INJEC-
TION

Engine: Return to the original
trouble condition

Change the amount of fuel injec-
tion using CONSULT-II.If trouble symptom disappears, see
CHECK ITEM.

Harness and connectors

Fuel injector

Heated oxygen sensor 1
IGNITION TIM-
ING

Engine: Return to the original
trouble condition

Timing light: Set

Retard the ignition timing using
CONSULT-II.If trouble symptom disappears, see
CHECK ITEM.

Perform Idle Air Volume Learning.
POWER BAL-
ANCE

Engine: After warming up, idle
the engine.

A/C switch: OFF

Shift lever: P or N

Cut off each fuel injector signal
one at a time using CONSULT-II.Engine runs rough or dies.

Harness and connectors

Compression

Fuel injector

Power transistor

Spark plug

Ignition coil
COOLING FAN*

Ignition switch: ON

Turn the cooling fan “HI”, “MID”,
“LOW” and “OFF” using CON-
SULT-II.Cooling fan moves and stops.
Harness and connectors

Cooling fan motor

IPDM E/R
ENG COOLANT
TEMP

Engine: Return to the original
trouble condition

Change the engine coolant tem-
perature using CONSULT-II.If trouble symptom disappears, see
CHECK ITEM.

Harness and connectors

Engine coolant temperature sen-
sor

Fuel injector
FUEL PUMP
RELAY

Ignition switch: ON (Engine
stopped)

Turn the fuel pump relay “ON”
and “OFF” using CONSULT-II
and listen to operating sound.Fuel pump relay makes the operat-
ing sound.
Harness and connectors

Fuel pump relay

EC-434
[VQ]
TROUBLE DIAGNOSIS

When you are inspecting the circuit by gently shaking (or twisting) the suspicious connectors, compo-
nents and harness in the DTC Confirmation Procedure, the moment a malfunction is found the DTC/1st
trip DTC will be displayed. (Refer to “INCIDENT SIMULATION TESTS” in GI-24, "
How to Perform Effi-
cient Diagnosis for an Electrical Incident" .)
2. “MANU TRIG”

If the malfunction is displayed as soon as “DATA MONITOR” is selected, reset CONSULT-II to “MANU
TRIG”. By selecting “MANU TRIG” you can monitor and store the data. The data can be utilized for fur-
ther diagnosis, such as a comparison with the value for the normal operating condition.
CONSULT-II Reference Value in Data Monitor ModeBBS004YG
Remarks:

Specification data are reference values.

Specification data are output/input values which are detected or supplied by the ECM at the connector.
* Specification data may not be directly related to their components signals/values/operations.
i.e. Adjust ignition timing with a timing light before monitoring IGN TIMING, because the monitor may show the specification data in
spite of the ignition timing not being adjusted to the specification data. This IGN TIMING monitors the data calculated by the ECM
according to the signals input from the camshaft position sensor and other ignition timing related sensors.
PBIB0197E
MONITOR ITEM CONDITION SPECIFICATION
ENG SPEED

Run engine and compare CONSULT-II value with the tachometer indica-
tion.Almost the same speed as the
tachometer indication.
MAS A/F SE-B1 See EC-440, "
TROUBLE DIAGNOSIS - SPECIFICATION VALUE" .
B/FUEL SCHDL See EC-440, "
TROUBLE DIAGNOSIS - SPECIFICATION VALUE" .
A/F ALPHA-B1
A/F ALPHA-B2See EC-440, "
TROUBLE DIAGNOSIS - SPECIFICATION VALUE" .
COOLAN TEMP/S

Engine: After warming up More than 70°C (158°F)
HO2S1 (B1)
HO2S1 (B2)

Engine: After warming up Maintaining engine speed at 2,000 rpm 0 - 0.3V ←→ Approx. 0.6 - 1.0V

TROUBLE DIAGNOSIS
EC-435
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HO2S2 (B1)
HO2S2 (B2)

Revving engine from idle to 3,000 rpm quickly after the following condi-
tions are met
–Engine: After warming up
–Keeping engine speed between 3,500 and 4,000 rpm for 1 minute and at
idle for 1 minute under no load0 - 0.3V ←→ Approx. 0.6 - 1.0V
HO2S1 MNTR (B1)
HO2S1 MNTR (B2)

Engine: After warming up Maintaining engine speed at 2,000 rpmLEAN ←→ RICH
Changes more than 5 times dur-
ing 10 seconds
HO2S2 MNTR (B1)
HO2S2 MNTR (B2)

Revving engine from idle to 3,000 rpm quickly after the following condi-
tions are met
–Engine: After warming up
–Keeping engine speed between 3,500 and 4,000 rpm for 1 minute and at
idle for 1 minute under no load.LEAN ←→ RICH
VEH SPEED SE

Turn drive wheels and compare CONSULT-II value with the speedometer
indication.Almost the same speed as the
speedometer indication
BATTERY VOLT

Ignition switch: ON (Engine stopped) 11 - 14V
ACCEL SEN 1

Ignition switch: ON
(Engine stopped)Accelerator pedal: Fully released 0.65 - 0.87V
Accelerator pedal: Fully depressed More than 4.3V
ACCEL SEN 2*

Ignition switch ON
(Engine stopped)Accelerator pedal: Fully released 0.56 - 0.96V
Accelerator pedal: Fully depressed More than 4.0V
THRTL SEN 1
THRTL SEN 2*

Ignition switch: ON
(Engine stopped)

Shift lever: DAccelerator pedal: Fully released More than 0.36V
Accelerator pedal: Fully depressed Less than 4.75V
START SIGNAL

Ignition switch: ON → START → ON OFF → ON → OFF
CLSD THL POS

Ignition switch: ON
(Engine stopped)Accelerator pedal: Fully released ON
Accelerator pedal: Slightly depressed OFF
AIR COND SIG

Engine: After warming up,
idle the engineAir conditioner switch: OFF OFF
Air conditioner switch: ON
(Compressor operates.)ON
P/N POSI SW

Ignition switch: ONShift lever: P or N ON
Shift lever: Except above OFF
PW/ST SIGNAL

Engine: After warming up,
idle the engineSteering wheel: Not being turned OFF
Steering wheel: Being turned ON
LOAD SIGNAL

Ignition switch: ONRear window defogger switch is ON and/
or lighting switch is in 2nd.ON
Rear window defogger switch is OFF and
lighting switch is OFF.OFF
IGNITION SW

Ignition switch: ON → OFF → ON ON → OFF → ON
HEATER FAN SW

Engine: After warming up,
idle the engineHeater fan: Operating. ON
Heater fan: Not operating OFF
BRAKE SW

Ignition switch: ONBrake pedal: Fully released OFF
Brake pedal: Slightly depressed ON
INJ PULSE-B1
INJ PULSE-B2

Engine: After warming up

Shift lever: P or N

Air conditioner switch: OFF

No loadIdle 2.0 - 3.0 msec
2,000 rpm 1.9 - 2.9 msec MONITOR ITEM CONDITION SPECIFICATION

TROUBLE DIAGNOSIS
EC-437
[VQ]
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*: Accelerator pedal position sensor 2 signal and throttle position sensor 2 signal are converted by ECM internally. Thus, they differ from
ECM terminals voltage signal.I/P PULLY SPD

Vehicle speed: More than 20 km/h (12 MPH)Almost the same speed as the
tachometer indication
VEHICLE SPEED

Turn drive wheels and compare CONSULT-II value with the speedometer
indication.Almost the same speed as the
speedometer indication
O2SEN HTR DTY

Engine coolant temperature when engine started: More than 80°C
(176°F)

Engine speed: Below 3,600 rpmApprox. 40%
AC PRESS SEN

Engine: Idle

Both A/C switch and blower fan switch: ON (Compressor operates)1.0 - 4.0V
VEH SPEED SE

Turn drive wheels and compare CONSULT-II value with the speedometer
indication.Almost the same speed as the
speedometer indication
SET VHCL SPD

Engine: Running ASCD: Operating.The preset vehicle speed is dis-
played.
MAIN SW

Ignition switch: ONMAIN switch: Pressed ON
MAIN switch: Released OFF
CANCEL SW

Ignition switch: ONCANCEL switch: Pressed ON
CANCEL switch: Released OFF
RESUME/ACC SW

Ignition switch: ONRESUME/ACCELERATE switch: Pressed ON
RESUME/ACCELERATE switch:
ReleasedOFF
SET SW

Ignition switch: ONSET/COAST switch: Pressed ON
SET/COAST switch: Released OFF
BRAKE SW1

Ignition switch: ONBrake pedal: Fully released ON
Brake pedal: Slightly depressed OFF
BRAKE SW2

Ignition switch: ONBrake pedal: Fully released OFF
Brake pedal: Slightly depressed ON
CRUISE LAMP

Ignition switch: ONMAIN switch: Pressed at the 1st time →
at the 2nd timeON → OFF
SET LAMP

MAIN switch: ON

Vehicle speed: Between 40
km/h (25 MPH) and 144 km/
h (89 MPH)SET/COAST switch pressed ON
SET/COAST switch released OFF MONITOR ITEM CONDITION SPECIFICATION