Electrical System DTC Based Diagnostics
U0101 - Lost Communication with Transmission Control Module
For a complete wiring diagram, refer to.
• When Monitored: Ignition ON. Battery voltage between 10 and 16 volts. Ignition-off draw fuse installed. Totally integrated power module is configured correctly.
• Set Condition: Bus messages not received from the transmission control module for approximately 2 to 5 seconds.
Test Step 1 - Verify the 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
• Perform the Stored Lost Communication procedure. Refer to => Non-DTC Based Diagnostics.
Test Step 2 - Test for Any of the Following Active DTCs
• With the scan tool, read all Active DTCs from all modules.
• Test for TIPM configuration, CAN C hardware electrical, VIN Missing/Mismatch, battery or ignition related DTCs.
Does the scan tool display any active DTCs for the conditions listed?
Yes
• Perform the appropriate Diagnostic Procedure.
No
• Go to Test Step 3.
Test Step 3 - Verify that the TCM Is Active on the Bus
• Turn the ignition ON.
• With the scan tool, select network diagnostics.
• Verify the TCM is active on the bus.
Is the TCM active on the bus?
Yes
• Go to Test Step 4.
No
• Perform the No Response Diagnostic Procedure. Refer to => Non-DTC Based Diagnostics.
Test Step 4 - Test for Additional Communication Related DTCs
• With the scan tool, select network diagnostics.
Is there more than one module with active DTCs logged against the TCM?
Yes
• Replace/update the transmission control module.
• Perform the Transmission Verification Test. Refer to => Non-DTC Based Diagnostics. Transmission Verification Test
No
• Go to Test Step 5.
Test Step 5 - Clear DTC in the Module Setting the Fault
• With the scan tool, select the module setting the DTC against the TCM.
• Clear Active DTCs.
Is this DTC still Active?
Yes
• Replace/update the module that set this DTC.
• Perform the appropriate Verification Test.
No
• Go to Test Step 6.
Test Step 6 - Cycle the 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.
Test Step 7 - Test for Additional Lost Communication Faults
• With the scan tool, select network diagnostics.
Do 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.
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 circuit for a short to voltage.
• Perform the Body Verification Test. Refer to => Non-DTC Based Diagnostics. 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 circuit for a short to ground.
• Perform the Body Verification Test. Refer to => Non-DTC Based Diagnostics. Body Interior
No
• Replace/update the module that set this DTC.
• Perform the appropriate Verification Test.