U0168-LOST COMMUNICATION WITH VEHICLE SECURITY CONTROL MODULE (WCM)

For a complete wiring diagram, refer to the Wiring Information.

When Monitored:
With the ignition on.

Battery voltage between 10 and 16 volts.

Ignition Off Draw (IOD) fuse installed.

Totally Integrated Power Module (TIPM) is configured correctly.
Set Condition:
Bus messages not received from the Wireless Control Module (WCM) for approximately two to five seconds.

Possible Causes
(D65) CAN C BUS (+) CIRCUIT SHORTED TO VOLTAGE
(D64) CAN C BUS (-) CIRCUIT SHORTED TO GROUND
DTCS RELATED TO BATTERY VOLTAGE, IGNITION, OR VIN MESSAGES
TIPM NOT CONFIGURED CORRECTLY
WCM POWER AND GROUND
WIRELESS CONTROL MODULE (WCM)
MODULE THAT SET THIS DTC

1. VERIFY THE DIAGNOSTIC TROUBLE CODE (DTC) IS ACTIVE

NOTE: Make sure the IOD fuse is installed and battery voltage is between 10 and 16 volts before proceeding.

1.	With the scan tool, read active DTCs.

Is this DTC active?

Yes

Go To 2

(Refer to 29 - Non-DTC Diagnostics/Communication - Diagnosis and Testing) and perform the STORED LOST COMMUNICATION DTCS diagnostic procedure.

2. CHECK FOR ANY OF THE FOLLOWING ACTIVE DTCS

1.	With the scan tool, read all active DTCs from all modules.

NOTE: Check for TIPM configuration, CAN C hardware electrical, VIN Missing/Mismatch, battery or ignition related DTCs.

Does the scan tool display any active DTCs to the conditions listed above?

Yes

Go to and perform the appropriate diagnostic procedure.

Go To 3

3. VERIFY THE WCM IS ACTIVE ON THE BUS

1.	Turn the ignition on.

2.	With the scan tool, select Network Diagnostics.

3.	Verify the WCM is active on the bus.

Is the WCM active on the bus?

Yes

Go To 4

(Refer to 29 - Non-DTC Diagnostics/Communication - Diagnosis and Testing) and perform the NO RESPONSE FROM WCM diagnostic procedure.

4. CHECK FOR ADDITIONAL COMMUNICATION RELATED DTCS

1.	With the scan tool, select Network Diagnostics.

Is there more than one module with active DTCs “Logged Against” the WCM?

Yes

Replace/update the WCM in accordance with the Service Information.
Perform the WIRELESS CONTROL MODULE (WCM) VERIFICATION. (Refer to 28 - DTC-Based Diagnostics/MODULE, Wireless Control (WCM) - Standard Procedure).

Go To 5

5. CLEAR DTC IN MODULE SETTING FAULT

1.	With the scan tool, select the module setting the DTC against the WCM.

2.	Clear active DTCs.

Is this DTC still active?

Yes

Replace/update the module that set this DTC in accordance with the Service Information.
Perform the appropriate verification test for the module being replaced. If there is no verification test for the associated module perform the BODY VERIFICATION TEST. (Refer to 28 - DTC-Based Diagnostics/MODULE, Totally Integrated Power (TIPM) - Standard Procedure).

Go To 6

6. CYCLE IGNITION

1.	Cycle the ignition from RUN to OFF three time ending with the key in the RUN position.

Does this DTC become active?

Yes

Go To 7

The condition is not present at this time. Using the wiring diagram/schematic as a guide, inspect the wiring for chafed, pierced, pinched, and partially broken wires and the wiring harness connectors for broken, bent, pushed out, and corroded terminals.
Perform the appropriate VERIFICATION TEST.

7. CHECK FOR ADDITIONAL LOST COMMUNICATION FAULTS

1.	With the scan tool, select Network Diagnostics.

Does the TIPM and other CAN C BUS modules show Lost Communication with the remaining CAN C BUS modules?

Yes

Go To 8

Replace/update the module that set this DTC in accordance with the Service Information.
Perform the appropriate verification test for the module being replaced. If there is no verification test for the associated module perform the BODY VERIFICATION TEST. (Refer to 28 - DTC-Based Diagnostics/MODULE, Totally Integrated Power (TIPM) - Standard Procedure).

8. (D65) CAN C BUS (+) CIRCUIT SHORTED TO VOLTAGE

1.	Measure the voltage between the (D65) CAN C Bus (+) circuit and ground.

Is the voltage above 5.0 volts?

Yes

Repair the short to voltage in the (D65) CAN C Bus (+) circuit.
Perform the BODY VERIFICATION TEST. (Refer to 28 - DTC-Based Diagnostics/MODULE, Totally Integrated Power (TIPM) - Standard Procedure).

Go To 9

9. (D64) CAN C BUS (-) CIRCUIT SHORTED TO GROUND

1.	Turn the ignition off.

2.	Measure the resistance between ground and the (D64) CAN C Bus (-) circuit.

Is the resistance below 10k Ohms?

Yes

Repair the short to ground in the (D64) CAN C Bus (-) circuit.
Perform the BODY VERIFICATION TEST. (Refer to 28 - DTC-Based Diagnostics/MODULE, Totally Integrated Power (TIPM) - Standard Procedure).

Replace/update the module that set this DTC in accordance with the Service Information.
Perform the appropriate verification test for the module being replaced. If there is no verification test for the associated module perform the BODY VERIFICATION TEST. (Refer to 28 - DTC-Based Diagnostics/MODULE, Totally Integrated Power (TIPM) - Standard Procedure).

U0168-LOST COMMUNICATION WITH VEHICLE SECURITY CONTROL MODULE (WCM)

Possible Causes