2010 Cadillac Truck Escalade RWD V8-6.0L Hybrid Page 3315

2010 Cadillac Truck Escalade RWD V8-6.0L Hybrid Page 3315

* Supply voltage at the control modules are in the normal operating range.

* The vehicle power mode requires serial data communications.

Conditions for Setting the DTC

The control module setting the DTC has attempted to establish communications on the serial data circuits more than 3 times in 5 seconds.

Action Taken When the DTCs Sets

* The module suspends all message transmission.

* The module uses default values for all parameters received on the serial data circuits.

* In the TCM, DTC U0073 will cause the transmission to go into default gears.

* In the ECM and TCM, DTC U0073 will cause the malfunction indicator lamp (MIL) to illuminate.

* The module inhibits the setting of all other communication DTCs.

Conditions for Clearing the DTC

* The ECM/TCM modules turn OFF the MIL after 4 consecutive ignition cycles that the diagnostic runs and does not fail.

* A current DTC clears when the malfunction is no longer present.

* A history DTC clears when the control module ignition cycle counter reaches the reset threshold of 50, without a repeat of the malfunction.

Circuit/System Verification

1. Refer to Data Link References (See: Powertrain Management/Computers and Control Systems/Information Bus/Testing and

Inspection/Initial Inspection and Diagnostic Overview) to determine which serial data system is used for a specific control module.

2. This DTC cannot be retrieved with a current status. Diagnosis is accomplished using the symptom Scan Tool Does Not Communicate with

High Speed GMLAN Device (See: Powertrain Management/Computers and Control Systems/Information Bus/Testing and

Inspection/Symptom Related Diagnostic Procedures/Scan Tool Does Not Communicate with High Speed GMLAN Device) or Scan Tool

Does Not Communicate with Low Speed GMLAN Device (See: Powertrain Management/Computers and Control Systems/Information

Bus/Testing and Inspection/Symptom Related Diagnostic Procedures/Scan Tool Does Not Communicate with Low Speed GMLAN Device).

U2100

DTC U2100

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic System

Check - Vehicle) prior to using this diagnostic procedure.

* Review Strategy Based Diagnosis (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Strategy Based Diagnosis) for an

overview of the diagnostic approach.

* Diagnostic Procedure Instructions (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic Procedure

Instructions) provides an overview of each diagnostic category.

DTC Descriptor

DTC U2100 00

- Controller Area Network (CAN) Bus Communication

Circuit Description

The GMLAN serial data circuits are controller area network (CAN) serial data buses used to communicate information between the control

modules. Typical data transmission speeds must be high enough to ensure that a required real-time response is maintained. On this vehicle there are

2 totally different types of GMLAN serial data circuits, the high speed 2-wire circuit and low speed single wire circuit. Refer to Data Link

Communications Description and Operation (See: Powertrain Management/Computers and Control Systems/Information Bus/Description and

Operation) for the complete description of these buses. The GMLAN serial data circuits also communicate directly to the DLC connector. Messages

are interpreted by the externally connected CANdi module which acts as a transceiver for the scan tool.

Modules connected to the GMLAN serial data circuits monitor communications during normal vehicle operation, where operation information is

exchanged among the modules. All the modules on the GMLAN networks, maintain a transmit error counter (TEC) and a receive error counter

(REC). The counter values increase with detected errors and will decrease with error-free messages. If the TEC value exceeds 255, the controller

removes itself from the network and DTC U2100 will result.

Conditions for Running the DTCs

* Supply voltage to the modules are in the normal operating range.

* The vehicle is in the RUN power mode.

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