4L30-E Automatic Transmission

Schematic:

Circuit Description with 4L30-E Automatic Transmission
The Controller Area Network (CAN) is used to receive and transmit data between the Engine Control Module (ECM), the Electronic Brake/Traction Control Module (EBTCM), and the Transmission Control Module (TCM). Each module sends signals by toggling the circuit either high or low to produce pulse-width signals, which the other modules decode. Circuits XR888 and XY888 are the CAN information lines used to transmit the data between the modules.
The CAN data stream contains status messages for relevant operating parameters, as well as state-of-health messages.

When the TCM has exceeded time out requirements to re-establish network communication, then DTC U2104 will set. DTC U2104 is a type B DTC.

CONDITION FOR RUNNING THE DTC
The ignition switch is in the RUN position.

CONDITION FOR SETTING THE DTC
The TCM has a loss of communication and has exceeded 40 time out requirements.

ACTION TAKEN WHEN THE DTC SETS
^ The TCM flashes the sport mode lamp and sends a MIL request to the ECM on the second consecutive drive trip that the diagnostic runs and fails. The ECM then illuminates the MIL.
^ The ECM records the operating conditions in the Freeze Frame at the time of the MIL request from the TCM.
^ The transmission operates in the default mode (maximum line pressure, command 4th gear, inhibit TCC, freeze shift adapts).

CONDITIONS FOR CLEARING THE MIL/DTC
^ The ECM turns off the MIL after three consecutive drive trips during which the TCM sends no MIL request.
^ A History DTC clears after forty consecutive warm-up cycles, if no failures are present by this diagnostic or any other emission related diagnostic.
^ The scan tool clears the MIL/DTC.
^ The TCM cancels the DTC default mode actions when the ignition switch is Off long enough in order to power down the TCM.

DIAGNOSTIC AIDS
Use the J 35616-A connector test adapter kit for any test that requires probing the TCM harness connector or a component harness connector. Using this kit will prevent damage to the harness connector terminals.

Check for the following conditions:
^ Poor connections at the TCM or at the component. Inspect the harness connectors for any backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and poor terminal to wire connection.
Refer to General Electrical Diagnosis Procedures in Diagrams for proper procedure.
^ Damaged harness. Inspect the wiring harness for damage. If the harness appears to be OK, observe the scan tool while moving any related connectors and any wiring harnesses. A change in the display may help to locate the fault.

TEST DESCRIPTION

Diagnostic Chart:

The number below refers to the step number on the diagnostic table.
2. Performing this step verifies that an operational abnormality did not take place during TCM power-up, such as Electromagnetic Interference (EMI).