Nissan Titan. Manual - part 112

DLN-20

< DTC/CIRCUIT DIAGNOSIS >

[TRANSFER: TX15B]

P1801, P1811 POWER SUPPLY CIRCUIT FOR TRANSFER CONTROL UNIT

DTC/CIRCUIT DIAGNOSIS

P1801, P1811 POWER SUPPLY CIRCUIT FOR TRANSFER CONTROL
UNIT

Description

INFOID:0000000009885957

The transfer control unit controls the transfer control device which controls shifts between 4H and 4LO and

between 2WD and 4WD.  When the vehicle battery is removed, the power supply to the transfer control unit is

interrupted, and self-diagnosis memory function is suspended.  DTCs P1801, P1811 or flash code 8 may also

set when the power supply voltage for the transfer control unit is abnormally low while driving.

DTC Logic

INFOID:0000000009885958

DTC DETECTION LOGIC

DTC CONFIRMATION PROCEDURE

1.

DTC CONFIRMATION PROCEDURE

1. Turn ignition switch ON.

2. Perform self-diagnosis.
Are DTCs P1801, P1811 or flash code 8 detected?

YES

>> Perform diagnosis procedure. Refer to 

DLN-20, "Diagnosis Procedure"

.

NO

>> Inspection End.

Diagnosis Procedure

INFOID:0000000009885959

Regarding Wiring Diagram information, refer to 

DLN-62, "Wiring Diagram"

.

1.

CHECK POWER SUPPLY

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

2. Disconnect transfer control unit harness connector.

3. Check voltage between transfer control unit harness connector

terminals and ground.

DTC

CONSULT

Diagnostic item is detected when...

Reference

[P1801]

*INITIAL START*

Due to removal of battery which cuts off 
power supply to transfer control unit, 
self-diagnosis memory function is sus-
pended.

DLN-20, "Diagnosis Procedure"

[P1811]

BATTERY VOLTAGE

Power supply voltage for transfer control 
unit is abnormally low while driving.

Connector

Terminal

Voltage (Approx.)

E142

19 - Ground

Battery voltage

25 - Ground

0V

E143

40 - Ground

Battery voltage

44 - Ground

0V

45 - Ground

SDIA3360E

P1801, P1811 POWER SUPPLY CIRCUIT FOR TRANSFER CONTROL UNIT

DLN-21

< DTC/CIRCUIT DIAGNOSIS >

[TRANSFER: TX15B]

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4. Turn ignition switch ON. (Do not start engine.)

5. Check voltage between transfer control unit harness connector

terminals and ground.

OK or NG

OK

>> GO TO 2.

NG

>> Check the following. If any items are damaged, repair or replace damaged parts.

• 10A fuses [No. 26 located in the fuse and fusible link box or 59 located in the fuse and relay box]

• 20A fuse [No. 53, located in the IPDM E/R]

• Harness for short or open between battery and transfer control unit harness connector E142 ter-

minal 19.

• Harness for short or open between battery and transfer shut off relay 2 harness connector E47

terminal 1 and 5.

• Harness for short or open between battery and transfer shut off relay 1 harness connector E46

terminal 5.

• Harness for short or open between ignition switch and transfer control unit harness connector

E142 terminal 25.

• Harness for short or open between ignition switch and transfer shut off relay 1 harness connec-

tor E46 terminal 2.

• Harness for short or open between transfer shut off relay 2 harness connector E47 terminal 3

and transfer control unit harness connector E143 terminals 44, 45.

• Harness for short or open between transfer shut off relay 1 harness connector E46 terminal 3

and transfer control unit harness connector E143 terminals 44, 45.

• Harness for short or open between transfer shut off relay 2 harness connector E47 terminal 2

and transfer control unit harness connector E143 terminal 40.

• Harness for open between transfer shut off relay 1 harness connector E46 terminal 1 and

ground.

• Battery and ignition switch.

• Transfer shut off relay 1, 2. Refer to COMPONENT INSPECTION .

2.

CHECK GROUND CIRCUIT

1. Turn ignition switch OFF.

2. Disconnect transfer control unit harness connector.

3. Check continuity between transfer control unit harness connec-

tor E142 terminals 6 and 18, and E143 terminal 32 and ground.

Also check harness for short to power.

OK or NG

OK

>> GO TO 3.

NG

>> Repair open circuit or short to power in harness or con-

nectors.

3.

CHECK TRANSFER CONTROL UNIT

Check transfer control unit input/output signal. Refer to 

DLN-56, "Reference Value"

.

OK or NG

OK

>> GO TO 4.

NG

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

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

Connector

Terminal

Voltage (Approx.)

E142

19 - Ground

Battery voltage

25 - Ground

E143

40 - Ground

44 - Ground

45 - Ground

SDIA3361E

Continuity should exist.

SDIA3362E

DLN-22

< DTC/CIRCUIT DIAGNOSIS >

[TRANSFER: TX15B]

P1801, P1811 POWER SUPPLY CIRCUIT FOR TRANSFER CONTROL UNIT

4.

CHECK DTC

Perform the self-diagnosis, after driving a vehicle for a while.
OK or NG

OK

>> Inspection End.

NG

>> Replace transfer control unit.  Refer to 

DLN-91, "Removal and Installation"

.

Component Inspection

INFOID:0000000009885960

1. Turn ignition switch OFF.  (Stay for at least 5 seconds.)
2. Remove transfer shut off relay 1 and transfer shut off relay 2. Refer to 

DLN-12, "Component Parts Loca-

tion"

.

3. Apply 12V direct current between transfer shut off relay termi-

nals 1 and 2.

4. Check continuity between relay terminals 3 and 5.

5. If inspection results are not normal, replace the transfer shut off

relay 1 or 2.

Condition

Continuity

12V direct current supply between terminals 1 and 2

Yes

OFF

No

SCIA1245E

P1802 – P1804, P1809 TRANSFER CONTROL UNIT

DLN-23

< DTC/CIRCUIT DIAGNOSIS >

[TRANSFER: TX15B]

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P1802 – P1804, P1809 TRANSFER CONTROL UNIT

Description

INFOID:0000000009885961

The transfer control unit controls the transfer control device which controls shifts between 4H and 4LO and

between 2WD and 4WD.  DTC P1802 - P1804 or P1809 may set when any of the following occur:

• Malfunction is detected in the memory (RAM) system of transfer control unit.

• Malfunction is detected in the memory (ROM) system of transfer control unit.

• Malfunction is detected in the memory (EEPROM) system of transfer control unit.

• AD converter system of transfer control unit is malfunctioning.

Flash code 5 may set when the following occurs:

• AD converter system of transfer control unit is malfunctioning.

DTC Logic

INFOID:0000000009885962

DTC DETECTION LOGIC

DTC CONFIRMATION PROCEDURE

1.

DTC CONFIRMATION PROCEDURE

1. Turn ignition switch ON.

2. Perform self-diagnosis.
Are DTCs P1802 - P1804, P1809 or flash code 5 detected?

YES

>> Perform diagnosis procedure. Refer to 

DLN-23, "Diagnosis Procedure"

.

NO

>> Inspection End.

Diagnosis Procedure

INFOID:0000000009885963

1.

INSPECTION START

Do you have CONSULT?
YES or NO

YES

>> GO TO 2.

NO

>> GO TO 3.

2.

PERFORM SELF-DIAGNOSIS (WITH CONSULT)

1. Turn ignition switch ON.

2. Select SELF-DIAG RESULTS mode for ALL MODE AWD/4WD with CONSULT.

3. Touch ERASE.

4. Turn ignition switch OFF and wait at least 10 seconds.

5. Perform the self-diagnosis again.
Is the CONTROL UNIT 1 [P1802], CONTROL UNIT 2 [P1803], CONTROL UNIT 3 [P1804] or CONTROL

UNIT 4 [P1809] displayed?

YES

>> Replace transfer control unit. Refer to 

DLN-91, "Removal and Installation"

.

NO

>> Inspection End.

3.

PERFORM SELF-DIAGNOSIS (WITHOUT CONSULT)

1. Perform the self-diagnosis and then erase self-diagnostic results.

DTC

CONSULT

Diagnostic item is detected when...

Reference

[P1802]

CONTROL UNIT 1

Malfunction is detected in the memory 
(RAM) system of transfer control unit.

DLN-23, "Diagnosis Procedure"

[P1803]

CONTROL UNIT 2

Malfunction is detected in the memory 
(ROM) system of transfer control unit.

[P1804]

CONTROL UNIT 3

Malfunction is detected in the memory 
(EEPROM) system of transfer control 
unit.

[P1809]

CONTROL UNIT 4

AD converter system of transfer control 
unit is malfunctioning.