Nissan Frontier D40. Manual - part 433
ECM
EC-423
< ECU DIAGNOSIS >
[QR25DE]
C
D
E
F
G
H
I
J
K
L
M
A
EC
N
P
O
• When there is an open circuit on MIL circuit, the ECM cannot warn the driver by illuminating MIL 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 MIL circuit is open by
means of operating the fail-safe function.
The fail-safe function also operates when above diagnoses except MIL circuit are detected, and demands
the driver to repair the malfunction.
DTC No.
Detected items
Engine operating condition in fail-safe mode
P0102
P0103
Mass air flow sensor circuit
Engine speed will not rise more than 2,400 rpm due to the fuel cut.
P0117
P0118
Engine coolant temperature
sensor circuit
Engine coolant temperature will be determined by ECM based on the following condi-
tion.
CONSULT-III displays the engine coolant temperature decided by ECM.
Condition
Engine coolant temperature decided (CONSULT-
III display)
Just as ignition switch is turned ON
or START
40
°
C (104
°
F)
Approx. 4 minutes or more after
engine starting
80
°
C (176
°
F)
Except as shown above
40 - 80
°
C (104 - 176
°
F)
(Depends on the time)
When the fail-safe system for engine coolant temperature sensor is activated, the cool-
ing fan operates while engine is running.
P0122
P0123
P0222
P0223
P2135
Throttle 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.
Therefore, the acceleration will be poor.
P0643
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.
P2100
P2103
Throttle 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.
P2101
Electric throttle control func-
tion
ECM stops the electric throttle control actuator control, throttle valve is maintained at a
fixed opening (approx. 5 degrees) by the return spring.
P2118
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.
P2119
Electric throttle control actu-
ator
(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 being driven, it slows down gradually because of fuel cut. After the
vehicle stops, the engine stalls.
The engine can restart in P or N (A/T), neutral position (M/T), and engine speed will not
exceed 1,000 rpm or more.
P2122
P2123
P2127
P2128
P2138
Accelerator pedal 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.
Therefore, 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