Infiniti QX56 (JA60). Manual - part 276

P1807 VEHICLE SPEED SENSOR (A/T)

DLN-27

< COMPONENT DIAGNOSIS >

[ATX14B]

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P1807 VEHICLE SPEED SENSOR (A/T)

Description

INFOID:0000000005148782

The transmission control module (TCM) transmits the output shaft revolution signal via CAN communication to

Transfer control unit.  DTC P1807 will set when a malfunction is detected in the output shaft revolution signal

or an improper signal is input while driving.

DTC Logic

INFOID:0000000005148783

DTC DETECTION LOGIC

DTC CONFIRMATION PROCEDURE

1.

DTC CONFIRMATION PROCEDURE

1. Turn ignition switch ON.

2. Perform self-diagnosis.
Is DTC P1807 detected?

YES

>> Perform diagnosis procedure. Refer to 

DLN-27, "Diagnosis Procedure"

.

NO

>> Inspection End.

Diagnosis Procedure

INFOID:0000000005148784

1.

CHECK DTC WITH TCM

Perform self-diagnosis with TCM. Refer to 

TM-32, "CONSULT-III Function (TRANSMISSION)"

.

Is any malfunction detected by self-diagnosis?

YES

>> Check the malfunctioning system.

NO

>> GO TO 2.

2.

CHECK TRANSFER CONTROL UNIT

Check transfer control unit input/output signal. Refer to 

DLN-81, "Reference Value"

.

Are the inspection results normal?

YES

>> GO TO 3.

NO

>> Check transfer control unit pin terminals for damage or loose connection with harness connector.

If any items are damaged, repair or replace damaged parts.

3.

CHECK DTC

Drive the vehicle and then perform self-diagnosis.
Are the inspection results normal?

YES

>> Inspection End.

NO

>> Perform self-diagnosis with TCM again.

DTC

CONSULT-III

Diagnostic item is detected when...

Reference

[P1807]

VHCL SPEED SEN·AT

• Malfunction is detected in output shaft 

revolution signal that is output from 
TCM through CAN communication.

• Improper signal is input while driving.

Refer to 

DLN-27

.

DLN-28

< COMPONENT DIAGNOSIS >

[ATX14B]

P1808 VEHICLE SPEED SENSOR (ABS)

P1808 VEHICLE SPEED SENSOR (ABS)

Description

INFOID:0000000005148785

The ABS actuator and electric unit (control unit) transmits a vehicle speed signal via CAN communication to

the transfer control unit.  DTC P1808 sets when a malfunction is detected in the vehicle speed signal that is

output from the ABS actuator and electric unit (control unit) or an improper signal is input while driving.

DTC Logic

INFOID:0000000005148786

DTC DETECTION LOGIC

DTC CONFIRMATION PROCEDURE

1.

DTC CONFIRMATION PROCEDURE

1. Turn ignition switch ON.

2. Perform self-diagnosis.
Is DTC P1808 displayed?

YES

>> Perform diagnosis procedure. Refer to 

DLN-28, "Diagnosis Procedure"

.

NO

>> Inspection End.

Diagnosis Procedure

INFOID:0000000005148787

1.

CHECK DTC WITH ABS ACTUATOR AND ELECTRIC UNIT (CONTROL UNIT)

Perform self-diagnosis with ABS actuator and electric unit (control unit). Refer to 

BRC-23, "CONSULT-III

Function (ABS)"

.

Is any malfunction detected by self-diagnosis?

YES

>> Check the malfunctioning system.

NO

>> GO TO 2.

2.

CHECK TRANSFER CONTROL UNIT

Check transfer control unit input/output signal. Refer to 

DLN-81, "Reference Value"

.

Are the inspection results normal?

YES

>> GO TO 3.

NO

>> Check transfer control unit pin terminals for damage or loose connection with harness connector.

If any items are damaged, repair or replace damaged parts.

3.

CHECK DTC

Perform the self-diagnosis, after driving a vehicle for a while.
Are the inspection results normal?

YES

>> Inspection End.

NO

>> Perform self-diagnosis with ABS actuator and electric unit (control unit) again.

DTC

CONSULT-III

Diagnostic item is detected when...

Reference

[P1808]

VHCL SPEED SEN·ABS

• Malfunction is detected in vehicle 

speed signal that is output from ABS 
actuator and electric unit (control unit) 
through CAN communication.

• Improper signal is input while driving.

Refer to 

DLN-28

.

P1810 NEUTRAL-4LO SWITCH

DLN-29

< COMPONENT DIAGNOSIS >

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P1810 NEUTRAL-4LO SWITCH

Description

INFOID:0000000005148788

The neutral-4LO switch detects that the transfer case is in neutral or 4LO range.  DTC P1810 will set when an

improper signal from the neutral-4LO switch is input due to an open or short circuit.

DTC Logic

INFOID:0000000005148789

DTC DETECTION LOGIC

DTC CONFIRMATION PROCEDURE

1.

DTC CONFIRMATION PROCEDURE

1. Turn ignition switch ON.

2. Perform self-diagnosis.
Is DTC P1810 displayed?

YES

>> Perform diagnosis procedure. Refer to 

DLN-29, "Diagnosis Procedure"

.

NO

>> Inspection End.

Diagnosis Procedure

INFOID:0000000005148790

Regarding Wiring Diagram information, refer to 

DLN-89, "Wiring Diagram - ALL-MODE 4WD SYSTEM -"

.

1.

CHECK 4LO POSITION SWITCH SIGNAL

With CONSULT-III

1. Start engine.

2. Select DATA MONITOR mode for ALL MODE AWD/4WD with CONSULT-III.

3. Read out the value of N POSI SW TF.

Without CONSULT-III

1. Start engine.

DTC

CONSULT-III

Diagnostic item is detected when...

Reference

[P1810]

4L POSI SW TF

Improper signal from neutral-4LO switch 
is input due to open or short circuit.

Refer to 

DLN-29

.

Condition

Display value

• Vehicle stopped
• Engine running
• A/T selector lever N position
• Brake pedal depressed

4WD shift switch: 2WD, 
AUTO or 4H

OFF

4WD shift switch: 4H to 
4LO (While actuator mo-
tor is operating.)

OFF 

→ ON

4WD shift switch: 4LO to 
4H (While actuator motor 
is operating.)

ON 

→ OFF

4WD shift switch: 4LO

ON

DLN-30

< COMPONENT DIAGNOSIS >

[ATX14B]

P1810 NEUTRAL-4LO SWITCH

2. Check voltage between transfer control unit harness connector

terminal and ground.

Are inspection results normal?

YES 

>> GO TO 5.

NO

>> GO TO 2.

2.

CHECK HARNESS BETWEEN TRANSFER CONTROL UNIT AND NEUTRAL-4LO SWITCH

1. Turn ignition switch OFF. (Stay for at least 5 seconds.)

2. Disconnect transfer control unit harness connector and the neutral-4LO switch harness connector.

3. Check continuity between transfer control unit harness connec-

tor E143 terminal 25 and neutral-4LO switch harness connector

F60 terminal 13.

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

Are inspection results normal?

YES

>> GO TO 3.

NO

>> Repair or replace damaged parts.

3.

CHECK GROUND CIRCUIT

1. Turn ignition switch OFF. (Stay for at least 5 seconds.)

2. Disconnect neutral-4LO switch harness connector.

3. Check continuity between neutral-4LO switch harness connec-

tor F60 terminal 12 and ground.

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

Are inspection results normal?

YES 

>> GO TO 4.

NO

>> Repair open circuit or short to ground or short to power

in harness or connectors.

4.

CHECK 4LO SWITCH 

1. Turn ignition switch OFF.

2. Disconnect neutral-4LO switch harness connector.

3. Remove neutral-4LO switch.

Connector

Terminal 

(Wire col-

or)

Condition

Voltage 

(Approx.)

E143

 25 - 

Ground

• Vehicle stopped
• Engine running
• A/T selector lever 

N position

• Brake pedal de-

pressed

4WD shift switch: 
2WD, AUTO or 4H

Battery 
voltage

4WD shift switch: 4H to 
4LO (While actuator 
motor is operating.)

Battery 
voltage 
→ 0V

4WD shift switch: 4LO 
to 4H (While actuator 
motor is operating.)

0V 

→ 

Battery 
voltage

4WD shift switch: 4LO

 0V

SDIA2693E

Continuity should exist.

SDIA2694E

Continuity should exist.

SDIA2695E