P1811

P1811 POWER SUPPLY CIRCUIT FOR TRANSFER CONTROL UNIT

Description
Power supply to transfer control unit is abnormally low while driving.

DTC Logic

P1811:

DTC CONFIRMATION PROCEDURE

1. DTC CONFIRMATION PROCEDURE
1. Turn ignition switch ON.
2. Perform self-diagnosis.
Is DTC P1811 detected?
YES >> Perform diagnosis procedure. Refer to "Diagnosis Procedure".
NO >> Inspection End.

Diagnosis Procedure

1. CHECK POWER SUPPLY
1. Turn ignition switch OFF. (Stay for at least 5 seconds.)
2. Connect transfer control unit harness connector.








3. Check voltage between transfer control unit harness connector terminals and ground.








4. Turn ignition switch ON. (Do not start engine.)
5. Check voltage between transfer control unit harness connector terminals and ground.
Are the inspection results normal?
YES >> GO TO 2.
NO >> Check the following. If any items are damaged, repair or replace damaged parts.
^ 10A fuses No. 26 located in fuse and fusible link box and No. 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 terminals 47.
^ Harness for short or open between battery and transfer control unit harness connector terminal 29.
^ Harness for short or open between battery and transfer shut off relay harness connector E69 terminal 1, and 3.
^ Harness for short or open between transfer shut off relay harness connector E69 terminal 2 and transfer control unit harness connector terminal 30.
^ Harness for short or open between transfer shut off relay harness connector E69 terminal 5 and transfer control unit harness connector terminals 16 and 22.
^ Battery and ignition switch.
^ Transfer shut off relay.

2. CHECK GROUND CIRCUIT
1. Turn ignition switch OFF. (Stay for at least 5 seconds.)
2. Disconnect transfer control unit harness connector.





3. Check continuity between transfer control unit harness connector E142 terminals 3, 6, E143 terminal 45 and ground.
Continuity should exist.
Also check harness for short to ground and short to power.
Are the inspection results normal?
YES >> GO TO 3.
NO >> Repair open circuit or short to ground or short to power in harness or connectors.

3. CHECK TRANSFER CONTROL UNIT
Check transfer control unit input/output signal. Refer to DLN-79, "Reference Value". Reference Value
Are the inspection results normal?
YES >> GO TO 4.
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.

4. CHECK DTC
Perform the self-diagnosis, after driving a vehicle for a while.
Are the inspection results normal?
YES >> Inspection End.
NO >> Replace transfer control unit.

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








3. Apply 12V direct current between transfer shut off relay terminals 1 and 2.
4. Check continuity between relay terminals 3 and 5.
5. If inspection results are abnormal replace the transfer shut off relay