Nissan Titan A60. Manual - part 321

P1837 CONTROL UNIT 4

DLN-223

< DTC/CIRCUIT DIAGNOSIS >

[REAR FINAL DRIVE: M226 (ELD) ]

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P1837 CONTROL UNIT 4

Description

INFOID:0000000006179586

Replace the differential lock control unit if this DTC is displayed. Refer to 

DLN-253, "Removal and Installation"

.

DTC Logic

INFOID:0000000006179587

DTC

Display contents of CONSULT-III

DTC Detection Condition

Action to take

P1837

CONTROL UNIT 4
[P1837]

The AD converter system of the differential lock control 
unit is malfunctioning. 

Replace differential lock 
control unit. Refer to 

DLN-

253, "Removal and Installa-
tion"

DLN-224

< DTC/CIRCUIT DIAGNOSIS >

[REAR FINAL DRIVE: M226 (ELD) ]

P1838 ON SWITCH

P1838 ON SWITCH

Description

INFOID:0000000006179588

The differential lock mode switch sends differential lock ON/OFF signals to the differential lock control unit.  

DTC Logic

INFOID:0000000006179589

Diagnosis Procedure

INFOID:0000000006179590

Regarding Wiring Diagram information, refer to 

DLN-240, "Wiring Diagram"

.

1.

CHECK DIFFERENTIAL LOCK MODE SWITCH OPERATION

1. Turn ignition switch ON.

2. Using CONSULT-III, select “D-LOCK SW SIG” of DIFF LOCK data monitor items.

3. While operating the differential lock mode switch, check that the display value changes between ON/OFF.

Is the inspection result normal?

YES

>> Differential lock mode switch is operating properly.

NO

>> GO TO 2.

2.

CHECK DIFFERENTIAL LOCK MODE SWITCH POWER SUPPLY CIRCUIT

1. Disconnect differential lock mode switch connector.

2. Turn ignition switch ON.

3. Check voltage between differential lock mode switch connector

M72 terminal 3 and ground.

Is the inspection result normal?

YES

>> GO TO 3.

NO

>> Repair harness or connector.

3.

CHECK DIFFERENTIAL LOCK MODE SWITCH SIGNAL

DTC

Display contents of CONSULT-III

DTC Detection Condition

Action to take

P1838

ON SW
[P1838]

Two switch inputs were simultaneously detected due to a 
short circuit in the differential lock mode switch. 

Inspect the differential lock 
mode switch. Refer to 

DLN-

224, "Diagnosis Procedure"

Switch ON

Display item ON

Switch OFF

Display item OFF

(+)

(-)

Voltage (Approx.)

Connector

Terminal

M72

 3

 Ground

Battery voltage

SDIA2534E

P1838 ON SWITCH

DLN-225

< DTC/CIRCUIT DIAGNOSIS >

[REAR FINAL DRIVE: M226 (ELD) ]

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1. Turn ignition switch OFF.

2. Connect differential lock mode switch connector.

3. Check voltage between differential lock control unit connector

B77 terminals 9, 22 and ground.

Is the inspection result normal?

YES 

>> Replace the differential lock control unit. Refer to 

DLN-253, "Removal and Installation"

.

NO

>> GO TO 4.

4.

CHECK DIFFERENTIAL LOCK MODE SWITCH

1. Turn ignition switch OFF.

2. Disconnect differential lock mode switch connector.

3. Operate differential lock mode switch and check continuity

between differential lock mode switch terminals.

Is the inspection result normal?

YES

>> GO TO 5.

NO

>> Replace differential lock mode switch.

5.

CHECK HARNESS BETWEEN DIFFERENTIAL LOCK CONTROL UNIT AND DIFFERENTIAL LOCK

MODE SWITCH

1. Check continuity between differential lock control unit connector

B77 (A) terminals 9, 22 and differential lock mode switch con-

nector M72 (B) terminals 2, 1.

2. Check continuity between differential lock control unit connector

B77 (A) terminals 9, 22 and ground. 

Is the inspection result normal?

 YES  >> Replace the differential lock control unit. Refer to 

DLN-253, "Removal and Installation"

.

 NO

>> Repair harness or connector.

(+)

(-)

Differential lock mode 

switch

Voltage (Approx.)

Connector

Terminal

B77

 9

Ground

ON

Battery voltage

OFF

0V

 22

ON

0V

OFF

Battery voltage

SDIA2568E

Terminals

Differential lock mode switch

Continuity

1 - 3

ON

No

OFF

Yes

2 - 3

ON

Yes

OFF

No

SDIA2535E

Connector

Terminal

Connector

Terminal

Continuity

B77 (A)

9

M72 (B)

2

Yes

22

1

Connector

Terminal

Ground

Continuity

B77 (A)

9

No

22

ALDIA0165ZZ

DLN-226

< DTC/CIRCUIT DIAGNOSIS >

[REAR FINAL DRIVE: M226 (ELD) ]

P1839 POSITION SWITCH ON

P1839 POSITION SWITCH ON

Description

INFOID:0000000006179591

The differential lock position switch sends a signal to the differential lock control module when the differential

lock is engaged. The differential lock control module monitors the left and right rear wheel speed sensor sig-

nals to determine wheel slippage. When the differential lock is engaged the left and right rear wheel speed

sensor signals should match. 

DTC Logic

INFOID:0000000006179592

Diagnosis Procedure

INFOID:0000000006179593

Regarding Wiring Diagram information, refer to 

DLN-240, "Wiring Diagram"

.

1.

CHECK DIFFERENTIAL LOCK POSITION SWITCH SIGNAL

1. Start engine.

2. Select “D-LOCK POS SW SIG” of DIFF LOCK data monitor.

3. Activate the differential lock according to the directions listed in the table and monitor the display value.

Is the inspection result normal?

YES

 >> Differential lock position switch is operating normally.

NO

>> GO TO 2.

2.

CHECK DIFFERENTIAL LOCK POSITION SWITCH

1. Disconnect differential lock position switch harness connector

C16.

2. Turn ignition switch ON.

3. Select “D-LOCK POS SW SIG” of DIFF LOCK data monitor.

4. Monitor the display value while connecting and disconnecting a

jumper wire between differential lock position switch terminals 1

and 3.

Is the inspection result normal?

YES

>> Check the mechanical operation of the differential lock. Replace the differential lock position

switch. Refer to 

DLN-254, "Removal and Installation"

.

NO

>> GO TO 3.

3.

CHECK DIFFERENTIAL LOCK POSITION SWITCH VOLTAGE

DTC

Display contents of CONSULT-III

DTC Detection Condition

Action to take

P1839

POSI SW ON
[P1839]

The differential lock position switch is ON indicating the 
differential is locked, but the differential lock control mod-
ule detects a difference between left and right rear wheel 
speeds. 

Inspect the differential lock 
position switch. Refer to 

DLN-226, "Diagnosis Proce-
dure"

.

Monitor item

Condition

Display value

D-LOCK POS SW SIG

• Vehicle stopped
• Engine running
• VDC OFF switch (if 

equipped): ON

• 4WD shift switch: 4LO

Differential lock mode switch: ON
(DIFF LOCK indicator lamp: ON)

ON

Differential lock mode switch: OFF
(DIFF LOCK indicator lamp: OFF)

OFF

Monitor item

Condition

Display value

D-LOCK POS SW SIG

Jumper wire connected

ON

Jumper wire disconnected

OFF

AWDIA0436ZZ