Operation CHARM: Car repair manuals for everyone.

Radio






Lost Communication with Vehicle Security Control Module






For a complete wiring diagram, refer to.

When Monitored: With the ignition on. Battery voltage between 10 and 16 volts. IOD fuse installed. TIPM is configured correctly.

Set Condition: Bus messages not received from the vehicle security control module (also known as the wireless control module) (SKREEM/WCM) for approximately 2 to 5 seconds.






Test Step 1 - Verify DTC is Active

Ensure the IOD fuse is installed and battery voltage is between 10 and 16 volts before proceeding.

With the scan tool, read active DTCs.

Is this DTC active?

Yes

Go to Test Step 2.

No

Refer to the table of contents in this section for the Stored Lost Communication test procedure.

Test Step 2 - Check for any of the Following Active DTCs

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

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

Diagnose and repair the DTC. Refer to the Index for a complete list of the symptoms.

No

Go to Test Step 3.

Test Step 3 - Verify that the WCM is Active on the Bus

Turn the ignition ON.

With the scan tool, select network diagnostics.

Verify that the WCM is active on the bus.

Is the WCM active on the bus?

Yes

Go to Test Step 4.

No

Refer to the table of contents in this section for the No Response test procedure.

Test Step 4 - Check for Additional Communication Related DTCs

With the scan tool, select network diagnostics.

Is there more than one module with active DTCs logged against the WCM?

Yes

Replace/update the wireless control module. Refer to.

Perform the appropriate Verification Test. Refer to => Non-DTC Based Diagnostics 00.

No

Go to Test Step 5.

Test Step 5 - Clear DTC in Module Setting Fault

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

Clear active DTCs.

Is this DTC still active?

Yes

Replace/update the module that set this DTC.

Perform the appropriate Verification Test. Refer to => Non-DTC Based Diagnostics 00.

No

Go to Test Step 6.

Test Step 6 - Cycle Ignition

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

Does this DTC become active?

Yes

Go to Test Step 7.

No

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. Refer to => Non-DTC Based Diagnostics 00.

Test Step 7 - Check for Additional Lost Communication Faults

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 Test Step 8.

No

Replace/update the module that set this DTC.

Perform the appropriate Verification Test. Refer to => Non-DTC Based Diagnostics 00.

Test Step 8 - CAN C Bus (+) Circuit Short to Voltage

Measure the voltage between the CAN C bus (+) circuit and ground.

Is the voltage more than 5 volts?

Yes

Repair the CAN C bus (+) circuit for a short to voltage.

Perform the Body Verification Test. Refer to => Non-DTC Based Diagnostics 00 Body Interior.

No

Go to Test Step 9.

Test Step 9 - CAN C Bus (-) Circuit Short to Ground

Turn the ignition OFF.

Measure the resistance between ground and the CAN C bus (-) circuit.

Is the resistance less than 10K ohms?

Yes

Repair the CAN C bus (-) circuit for a short to ground.

Perform the Body Verification Test. Refer to => Non-DTC Based Diagnostics 00 Body Interior.

No

Replace/update the module that set this DTC.

Perform the appropriate Verification Test. Refer to => Non-DTC Based Diagnostics 00.