Transfer Case

DTC U0122 CAN COMMUNICATION MALFUNCTION (ECM/PCM - VDC)

COMPONENT LOCATION
Refer to DTC U0001. U0001

GENERAL DESCRIPTION
Refer to DTC U0001. U0001

DTC DESCRIPTION
This code related to communication line between HECU (ESP) and "4WD-ECM" is set when CAN signal from HECU (ESP) can't received for more than 1 sec or ECU internal error occur.
If failure is detected "4WD-ECM" prohibits the "ITCC" control and cuts the current to control coil.

DTC DETECTING CONDITION:

SCHEMATIC DIAGRAM
Refer to DTC U0001. U0001

SIGNAL WAVEFORM & DATA
Refer to DTC U0001. U0001

MONITOR DTC STATUS
1. Connect Scantool to Data Link Connector (DLC).
2. Warm up the engine to normal operating temperature.
3. Monitor DTC (Diagnostics Trouble Code) on the Scantool.





4. Is the same DTC displayed again?
YES
- Go to "inspection/Repair" procedure.
NO
- Fault is intermittent caused by poor contact in the sensor's and/or "4WD-ECMs" connector or was repaired and "4WD-ECM" memory was not cleared.
Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage.
Repair or replace as necessary and go to "Verification of vehicle Repair" procedure

TERMINAL AND CONNECTOR INSPECTION
1. Many malfunctions in the electrical system are caused by poor harness and terminals. Faults can also be caused by interference from other electrical systems, and mechanical or chemical damage.
2. Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage.
3. Has a problem been found?
YES
- Repair as necessary and go to "Verification of Vehicle Repair" procedure.
NO
- Go to "Signal circuit inspection-CAN" procedure.

SIGNAL CIRCUIT INSPECTION
SIGNAL CIRCUIT INSPECTION-CAN
1. IG KEY: OFF
2. 4WD ECM, EMC connector: Connect.
3. IG KEY: ON, Engine: ON.
4. Monitor signal waveform between CAN (HIGH, LOW) of "4WD-ECM" harness connector and chassis ground.
5. Start and drive vehicle in gear and maintain vehicle speed is approximately 10 km/h or less (6 mph or less)
Specification: Signal Waveform & Data

CAUTION:
The above value is only for reference.
The actual value may differ from it according to various engine condition.

6. Is "Signal display" near the specified value?
YES
- Fault is intermittent caused by poor contact in the sensor's and/or "4WD-ECMs" connector or was repaired and "4WD-ECM" memory was not cleared.
Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage.
Repair or replace as necessary and go to "Verification of vehicle Repair" procedure.
NO
- Go to "CAN comm. Line inspection (Open/Short)" procedure.

CONTROL CIRCUIT INSPECTION
CAN COMM, LINE inspection (OPEN/SHORT)
1. Ignition OFF.
2. 4WD ECM: Disconnect.
3. Measure resistance between CAN (HIGH) terminal of 4WD ECM harness connector and CAN (LOW) terminal of 4WD ECM harness connector.
Specification: Approximately 60 Ohms

CAUTION:
The above value is only for reference.
The actual value may differ from it according to various engine condition.

4. Is "resistance" display near the specified value?
YES
- Fault is intermittent caused by open or short in CAN signal harness was repaired and "4WD-ECM" memory was not cleared.
Go to the applicable troubleshooting procedure.
NO
- Check for open or short in TCCU communication circuit.>
- Check HECU (ESP) or their signal.
- Repair or replace as necessary and go to "Verification of vehicle Repair" procedure.

VERIFICATION OF VEHICLE REPAIR
Refer to DTC U0001. U0001