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Infiniti F50. Manual - part 360

TROUBLE DIAGNOSIS

EC-81

Fail-safe Chart

EBS00LVX

When the DTC listed below is detected, the ECM enters fail-safe mode and the MIL lights up.

DTC No.

Detected items

Engine operating condition in fail-safe mode

P0102
P0103
P1102

Mass air flow sensor circuit

Engine speed will not rise more than 2,400 rpm due to the fuel cut.

P0117
P0118

Engine coolant tempera-
ture sensor circuit

Engine coolant temperature will be determined by ECM based on the time after turning
ignition switch “ON” or “START”.
CONSULT-II displays the engine coolant temperature decided by ECM.

Condition

Engine coolant temperature decided

(CONSULT-II display)

Just as ignition switch is turned
ON or START

C (104

More than approx. 4 minutes after
ignition ON or START

C (176

Except as shown above

40 - 80

C (104 - 176

(Depends on the time)

When the fail-safe system for engine coolant temperature sensor is activated, the cooling
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.
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:)
The 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 N or P position, and engine speed will not exceed 1,000 rpm or
more.

P1122

Electric throttle control
function

ECM stops the electric throttle control actuator control, throttle valve is maintained at a
fixed opening (approx. 5 degrees) by the return spring.

P1124
P1126

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.

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.

P2122
P2123
P2127
P2128
P2138

Accelerator pedal position
sensor

EC-82

TROUBLE DIAGNOSIS

Basic Inspection

EBS00LVY

INSPECTION START

Check service records for any recent repairs that may indicate a related malfunction, or a current need for
scheduled maintenance.

Open engine hood and check the following:

–

Harness connectors for improper connections

–

Wiring harness for improper connections, pinches and cut

–

Vacuum hoses for splits, kinks and improper connections

–

Hoses and ducts for leaks

–

Air cleaner clogging

–

Gasket

Confirm that electrical or mechanical loads are not applied.

–

Headlamp switch is OFF.

–

Air conditioner switch is OFF.

–

Rear window defogger switch is OFF.

–

Steering wheel is in the straight-ahead position, etc.

Start engine and warm it up until engine coolant temperature
indicator points the middle of gauge.
Ensure engine stays below 1,000 rpm.

Run engine at about 2,000 rpm for about 2 minutes under no
load.

Make sure that no DTC is displayed with CONSULT-II or GST.

OK or NG

>> GO TO 3.

>> GO TO 2.

REPAIR OR REPLACE

Repair or replace components as necessary according to corresponding “Diagnostic Procedure”.

>> GO TO 3

SEF983U

SEF976U

SEF977U

TROUBLE DIAGNOSIS

EC-83

CHECK TARGET IDLE SPEED

With CONSULT-II

Run engine at about 2,000 rpm for about 2 minutes under no load.

Rev engine (2,000 to 3,000 rpm) two or three times under no
load, then run engine at idle speed for about 1 minute.

Read idle speed in “DATA MONITOR” mode with CONSULT-II.

Without CONSULT-II

Run engine at about 2,000 rpm for about 2 minutes under no load.

Rev engine (2,000 to 3,000 rpm) two or three times under no load, then run engine at idle speed for about
1 minute.

Check idle speed.

OK or NG

>> GO TO 10.

>> GO TO 4.

PERFORM ACCELERATOR PEDAL RELEASED POSITION LEARNING

Stop engine.

Perform

EC-46, "Accelerator Pedal Released Position Learning"

>> GO TO 5.

PERFORM THROTTLE VALVE CLOSED POSITION LEARNING

Perform

EC-46, "Throttle Valve Closed Position Learning"

>> GO TO 6.

SEF978U

650

50 rpm (in “P” or “N” position)

SEF058Y

650

50 rpm (in “P” or “N” position)

EC-84

TROUBLE DIAGNOSIS

PERFORM IDLE AIR VOLUME LEARNING

Refer to

EC-46, "Idle Air Volume Learning"

Is Idle Air Volume Learning carried out successfully?

Yes or No

Yes

>> GO TO 7.

>> 1. Follow the instruction of “Idle Air Volume Learning”.

2. GO TO 4.

CHECK TARGET IDLE SPEED AGAIN

With CONSULT-II

Start engine and warm it up to normal operating temperature.

Read idle speed in “DATA MONITOR” mode with CONSULT-II.

Without CONSULT-II

Start engine and warm it up to normal operating temperature.

Check idle speed.

OK or NG

>> GO TO 10.

>> GO TO 8.

DETECT MALFUNCTIONING PART

Check the Following.

●

Check camshaft position sensor (PHASE) and circuit. Refer to

EC-315

●

Check crankshaft position sensor (POS) and circuit. Refer to

EC-307

OK or NG

>> GO TO 9.

>> 1. Repair or replace.

2. GO TO 4.

CHECK ECM FUNCTION

Substitute another known-good ECM to check ECM function. (ECM may be the cause of an incident, but
this is a rare case.)

Perform initialization of IVIS (NATS) system and registration of all IVIS (NATS) ignition key IDs. Refer to

BL-200, "ECM Re-communicating Function"

>> GO TO 4.

650

50 rpm (in “P” or “N” position)

650

50 rpm (in “P” or “N” position)

SEF058Y

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