Infiniti FX35, FX50 (S51). Manual - part 726

P2122, P2123 APP SENSOR

EC-445

< DTC/CIRCUIT DIAGNOSIS >

[VQ35HR]

C

D

E

F

G

H

I

J

K

L

M

A

EC

N

P

O

NO

>> GO TO 2.

2.

REPLACE ACCELERATOR PEDAL ASSEMBLY

1.

Replace accelerator pedal assembly.

2.

Go to 

EC-445, "Special Repair Requirement"

.

>> INSPECTION END

Special Repair Requirement

INFOID:0000000005237055

1.

PERFORM ACCELERATOR PEDAL RELEASED POSITION LEARNING

Refer to 

EC-25, "ACCELERATOR PEDAL RELEASED POSITION LEARNING : Special Repair Requirement"

.

>> GO TO 2.

2.

PERFORM THROTTLE VALVE CLOSED POSITION LEARNING

Refer to 

EC-25, "THROTTLE VALVE CLOSED POSITION LEARNING : Special Repair Requirement"

.

>> GO TO 3.

3.

PERFORM IDLE AIR VOLUME LEARNING

Refer to 

EC-25, "IDLE AIR VOLUME LEARNING : Special Repair Requirement"

.

>> END

EC-446

< DTC/CIRCUIT DIAGNOSIS >

[VQ35HR]

P2127, P2128 APP SENSOR

P2127, P2128 APP SENSOR

Description

INFOID:0000000005237056

The accelerator pedal position sensor is installed on the upper end
of the accelerator pedal assembly. The sensor detects the accelera-
tor position and sends a signal to the ECM.
Accelerator pedal position sensor has two sensors. These sensors
are a kind of potentiometer which transform the accelerator pedal
position into output voltage, and emit the voltage signal to the ECM.
In addition, these sensors detect the opening and closing speed of
the accelerator pedal and sends voltage signals to the ECM. The
ECM judges the current opening angle of the accelerator pedal from
these signals and controls the throttle control motor based on these
signals.
Idle position of the accelerator pedal is determined by the ECM
receiving the signal from the accelerator pedal position sensor. The ECM uses this signal for engine opera-
tions such as fuel cut.

DTC Logic

INFOID:0000000005237057

DTC DETECTION LOGIC

DTC CONFIRMATION PROCEDURE

1.

PRECONDITIONING

If DTC Confirmation Procedure has been previously conducted, always perform the following procedure
before conducting the next test.
1.

Turn ignition switch OFF and wait at least 10 seconds.

2.

Turn ignition switch ON.

3.

Turn ignition switch OFF and wait at least 10 seconds.

TESTING CONDITION:
Before performing the following procedure, confirm that battery voltage is more than 10 V at idle.

>> GO TO 2.

2.

PERFORM DTC CONFIRMATION PROCEDURE

1.

Start engine and let it idle for 1 second.

2.

Check DTC.

PBIB1741E

DTC No.

Trouble diagnosis name

DTC detecting condition

Possible cause

P2127

Accelerator pedal posi-
tion (APP) sensor 2 cir-
cuit low input

An excessively low voltage from the APP sen-
sor 2 is sent to ECM.

• Harness or connectors

(APP sensor 2 circuit is open or shorted.)
[Crankshaft position (CKP) sensor circuit 
is shorted.]
[Camshaft position (CMP) sensor (bank 
2) circuit is shorted.]
[Exhaust valve timing (EVT) control posi-
tion sensor (bank 2) circuit is shorted.]
(Battery current sensor circuit is shorted.)
(EVAP control system pressure sensor 
circuit is shorted.)
(Refrigerant pressure sensor circuit is 
shorted.)

• APP sensor (APP sensor 2)
• CKP sensor
• CMP sensor (bank 2)
• EVT control position sensor (bank 2)
• Battery current sensor
• EVAP control system pressure sensor
• Refrigerant pressure sensor

P2128

Accelerator pedal posi-
tion (APP) sensor 2 cir-
cuit high input

An excessively high voltage from the APP sen-
sor 2 is sent to ECM.

P2127, P2128 APP SENSOR

EC-447

< DTC/CIRCUIT DIAGNOSIS >

[VQ35HR]

C

D

E

F

G

H

I

J

K

L

M

A

EC

N

P

O

Is DTC detected?

YES

>> Go to 

EC-447, "Diagnosis Procedure"

.

NO

>> INSPECTION END

Diagnosis Procedure

INFOID:0000000005237058

1.

CHECK GROUND CONNECTION

1.

Turn ignition switch OFF.

2.

Check ground connection M95. Refer to Ground Inspection in 

GI-39, "Circuit Inspection"

.

Is the inspection result normal?

YES

>> GO TO 2.

NO

>> Repair or replace ground connection.

2.

CHECK ACCELERATOR PEDAL POSITION (APP) SENSOR 2 POWER SUPPLY CIRCUIT-I

1.

Disconnect APP sensor harness connector.

2.

Turn ignition switch ON.

3.

Check the voltage between APP sensor harness connector and ground.

Is the inspection result normal?

YES

>> GO TO 7.

NO

>> GO TO 3.

3.

CHECK APP SENSOR 2 POWER SUPPLY CIRCUIT-II

1.

Turn ignition switch OFF.

2.

Disconnect ECM harness connector.

3.

Check the continuity between APP sensor harness connector and ECM harness connector.

Is the inspection result normal?

YES

>> GO TO 5.

NO

>> GO TO 4.

4.

DETECT MALFUNCTIONING PART

Check the following.
• Harness connectors M6, E106
• Harness for open between ECM and APP sensor

>> Repair open circuit.

5.

CHECK APP SENSOR 2 POWER SUPPLY CIRCUIT-III

Check harness for short to power and short to ground, between the following terminals.

APP sensor

Ground

Voltage (V)

Connector

Terminal

E112

(Without ICC)

6

Ground

Approx. 5

E116

(With ICC)

3

APP sensor

ECM

Continuity

Connector

Terminal

Connector

Terminal

E112

(Without ICC)

6

M107

103

Existed

E116

(With ICC)

3

EC-448

< DTC/CIRCUIT DIAGNOSIS >

[VQ35HR]

P2127, P2128 APP SENSOR

Is the inspection result normal?

YES

>> GO TO 6.

NO

>> Repair short to ground or short to power in harness or connectors.

6.

CHECK COMPONENTS

Check the following.
• CKP (Refer to 

EC-271, "Component Inspection"

.)

• CMP sensor (bank 2) (Refer to 

EC-277, "Component Inspection"

.)

• EVT control position sensor (bank 2) (Refer to 

EC-369, "Component Inspection"

.)

• Battery current sensor (Refer to 

EC-400, "Component Inspection"

.)

• EVAP control system pressure sensor (Refer to 

EC-313, "Component Inspection"

.)

• Refrigerant pressure sensor (Refer to 

HAC-84, "Diagnosis Procedure"

.)

Is the inspection result normal?

YES

>> GO TO 13.

NO

>> Replace malfunctioning component.

7.

CHECK APP SENSOR 2 GROUND CIRCUIT FOR OPEN AND SHORT

1.

Turn ignition switch OFF.

2.

Disconnect ECM harness connector.

3.

Check the continuity between APP sensor harness connector and ECM harness connector.

4.

Also check harness for short to ground and short to power.

Is the inspection result normal?

YES

>> GO TO 9.

NO

>> GO TO 8.

8.

DETECT MALFUNCTIONING PART

Check the following.
• Harness connectors M6, E106
• Harness for open or short between ECM and APP sensor

>> Repair open circuit, short to ground or short to power in harness or connectors.

9.

CHECK APP SENSOR 2 INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT

ECM

Sensor

Connector

Terminal

Name

Connector

Terminal

F101

46

Crankshaft position (CKP) sensor

F2

1

F102

64

Camshaft position (CMP) sensor (bank 2)

F18

1

Exhaust valve timing (EVT) control position 
sensor (bank 2)

F19

1

Battery current sensor

E21

1

M107

103

APP sensor

E112

(Without ICC)

6

E116

(With ICC)

3

107

EVAP control system pressure sensor

B252

3

111

Refrigerant pressure sensor

E77

3

APP sensor

ECM

Continuity

Connector

Terminal

Connector

Terminal

E112

(Without ICC)

2

M107

104

Existed

E116

(With ICC)