Data Link Communication System Chevrolet Aveo I

Data Link Communications Schematic Icons

Data Link Communications Schematic Icons Icon Icon Definition CAUTION: When performing service on or near the SIR components or the SIR wiring, the SIR system must be disabled. Refer to SIR Disabling and Enabling Zones. Failure to observe the correct procedure could cause deployment of the SIR components, personal injury, or unnecessary SIR system repairs

Scheme 1

Scheme 2

Data Link Communications Connector End Views

Data Link Connector Connector Part Information MOLEX 51116-1601 16-Way F Metri-Pack 150 Series (BK) Pin Wire Color Circuit No. Function 1-3 - - Not Used 4 BK/WH 51 Ground 5 BK/WH 51 Ground 6 - - Not Used 7 BK/WH 2051 Transmission Control Module (TMC) Serial Data D-BU/WH 1800 Theft Serial Data (w/Immobilizer) BK/WH 2051 Theft Serial Data (w/o Immobilizer) BK/WH 2051 Electronic Brake Control Module (EBCM) Serial Data (w/ABS) 8 BK/WH 2051 Remote Control Door Lock Control (RCDLR) Serial Data 9-12 - - Not Used 13 BN 337 SIR Serial Data 14-15 - - Not Used 16 OG 440 Battery Positive Voltage

Scheme 3

Diagnostic Starting Point - Data Link Communications

Begin the diagnostic of the data link communications by performing the Diagnostic System Check for the system in which the customer concern is apparent. The Diagnostic System Check will direct you to the correct procedure within the Data Link Communications section when a communication malfunction is present.

Circuit Description

Modules that are connected to the shared communication circuits monitor for serial data communications during normal vehicle operation. Operating information and commands are exchanged among the modules. The modules have pre-recorded information about what messages are needed to be exchanged on the serial data circuits for each virtual network. The messages are usually supervised and some periodic messages are used by the receiver module as an availability indication of the transmitter module.

DTC Descriptors

This diagnostic procedure supports the following DTC

DTC U0101 Lost Communication With Transmission Control Module (TCM)

Conditions for Running the DTCs

1. The ignition is ON.
2. The DTC U0101 diagnostic runs continuously when the above condition is met.

Conditions for Setting the DTC

The engine control module (ECM) cannot communicate with the TCM.

Action Taken When the DTC Sets

1. The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

Conditions for Clearing the MIL/DTC

1. The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

Test Description

The numbers below refer to the step numbers in the diagnostic table.

1. 1: When the ECM stores a DTC U0101, a DTC U2105 simultaneously sets in the TCM. Performing the diagnostic procedures in DTC U2105 will repair DTC U0101.

DTC U0100-U0299

Symptoms - Data Link Communications

1. Perform the Diagnostic System Check for the subsystem exhibiting the symptoms. The subsystem diagnostic system check will identify where to begin diagnosis of the data link communication system.
2. Review the system operation in order to familiarize yourself with the system functions. Refer to «Data Link Communications Description and Operation»(/chevrolet/aveo/i-2003-2008/remont/communication-devices/#data-link-communication-system) .

Visual/Physical Inspection

1. Inspect for aftermarket devices that could affect the operation of the serial data communications systems. Refer to «Checking Aftermarket Accessories»(/chevrolet/aveo/i-2003-2008/remont/electrical-component-locations/#wiring-systems-electrical-power-management__checking-aftermarket-accessories) in Wiring Systems.
2. Inspect the easily accessible systems or visible system components for obvious damage or conditions that could cause the symptom.

Intermittents

Faulty electrical connections or wiring may be the cause of intermittent conditions. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.

Symptom List

Refer to a symptom diagnostic procedure from the following list in order to diagnose the symptom

1. «Data Link Connector Diagnosis»(/chevrolet/aveo/i-2003-2008/remont/communication-devices/#data-link-communication-system)
2. «Scan Tool Does Not Power Up»(/chevrolet/aveo/i-2003-2008/remont/communication-devices/#data-link-communication-system)
3. «Scan Tool Does Not Communicate with Component»(/chevrolet/aveo/i-2003-2008/remont/communication-devices/#data-link-communication-system)

The provision for communicating with the engine control module (ECM) is the data link connector (DLC). It is located under the instrument panel. The DLC is used to connect the scan tool. Battery power and ground is supplied for the scan tool through the DLC. The Keyword 2000 serial data circuit to the DLC allows the ECM to communicate with the scan tool. A universal asynchronous receiver transmitter (UART) serial data line is used to communicate with the other modules such as the electronic brake control module (EBCM), the supplemental inflatable restraint (SIR) system, and the instrument panel cluster (IPC).

Diagnostic Aids

Note. Refer to Defective Scan Tool Notice in Cautions and Notices.

Ensure that the correct application, model line, car year, etc., has been selected on the scan tool. If communication still cannot be established, try the scan tool on another vehicle to ensure that the scan tool or cables are not the cause of the condition.

An intermittent may be caused by a poor connection, rubbed through wire insulation, or a broken wire inside the insulation.

Any circuitry that is suspected of causing an intermittent complaint should be thoroughly inspected for the following conditions

1. Backed-out terminals
2. Improper mating of terminals
3. Broken locks
4. Improperly formed or damaged terminals
5. Poor terminal-to-wire connection
6. Physical damage to the wiring harness
7. Corrosion

The numbers below refer to the step numbers on the diagnostic table.

1. 1: The On-Board Diagnostic (EOBD) System Check prompts the technician to complete some basic checks and store the Freeze Frame and Failure Records data on the scan tool if applicable. This creates an electronic copy of the data taken when the malfunction occurred. The information is then stored on the scan tool for later reference.
2. 2: Unlike the UART serial data circuit, the only time a class 2 serial data circuit has any voltage on it is when a scan tool asks the ECM for information and sends the information out.
3. 5: Locate and repair any shorts that may have caused the fuse to open before replacement, if the no voltage condition was due to an open fuse.
4. 10: The scan tool or associated cables could be malfunctioning. Refer to the scan tool manual for repair information.

Data Link Connector Diagnosis

The provisions for communicating with the engine control module (ECM), electronic brake control module (EBCM), SIR module, immobilizer module, and the theft deterrent module are located in the data link connector (DLC). The DLC is located under the instrument panel (I/P). The 16 pin DLC provides the serial data signals at terminals 7 (ECM, TCM, immobilizer serial data), 8 (theft deterrent serial data), 12 (ABS serial data), and 13 (SIR serial data). The DLC is used to link a scan tool to the ECM, EBCM, SIR, immobilizer, and theft control modules serial data stream. Some common uses of the scan tool are listed below

1. Identifying the stored diagnostic trouble codes (DTCs)
2. Reading the serial data stream
3. Clearing the DTCs
4. Storing the Freeze Frame data

Some scan tools may require an external power supply. Ensure the scan tool is correctly connected to the power feed.

Ensure that the correct application (model year, carline, VIN code) has been selected on the scan tool. If communications are still not established, try the scan tool on another vehicle in order to ensure that the scan tool or the connecting cables are not the cause of the malfunction. Always try the scan tool on a vehicle that uses the same DLC terminal for serial data communication.

Any circuitry that is suspect to an intermittent complaint should be thoroughly inspected for the following

1. Backed-out terminals
2. Improper mating of terminals
3. Broken electrical connector locks
4. Improperly formed or damaged terminals
5. Faulty terminal-to-wiring connections
6. Physical damage to the wiring harness
7. A broken conductor inside the wire insulation
8. Corrosion of the electrical connections, the splices, or the terminals

The numbers below refer to the step numbers on the diagnostic table.

1. 3: This step checks whether the scan tool can communicate with other control modules on the vehicle. If the scan tool can communicate with one of the other modules then the DLC connector, the shared circuits, and the scan tool are OK.
2. 4: This step checks whether the ECM is receiving ignition positive voltage from the fuse F16 when the ignition is ON. The ECM cannot provide serial data without ignition positive voltage.
3. 7: This step checks for a high resistance or an open/short in the ECM serial data circuit.
4. 8: This step checks the ECM DLC Diagnostic circuit high resistance or open/short. This could cause the ECM not to communicate.
5. 9: This step checks to see if the EBCM is not communicating with the scan tool.
6. 14: This step checks to see if the SIR system is not communicating with the scan tool.
7. 19: This step checks to see if the theft deterrent-immobilizer system is not communicating with the scan tool.

Scan Tool Does Not Communicate with Component

The data link connector (DLC) provides operating power for the scan tool at terminal 16. The ground for the scan tool is provided at terminal 4. The 16- pin DLC provides the serial data signals at terminals 7 (engine control module (ECM), transmission control module (TCM), immobilizer serial data), 8 (theft deterrent serial data), 12 (ABS serial data), and 13 (SIR serial data). The scan tool will power up with the ignition OFF. The ignition must be ON in order for the scan tool to communicate with a control module.

The numbers below refer to the step numbers on the diagnostic table.

1. 1: Fuse F11 supplies power to terminal 16 of the DLC.
2. 4: The battery positive voltage and ground circuits of the DLC are functioning properly. The malfunction must be due to the scan tool.

Scan Tool Does Not Power Up

Regulations and agreements among the automobile manufacturers have resulted in the data link connector (DLC). This connector must be used for the scan tool and programming access to all communications systems used for the purposes on the vehicle. The connector must have the following

1. A 16-pin connector configuration to which all scan tools connect
2. Scan tool battery power always available at pin 16
3. Scan tool ground always available at pin 4
4. A clean signal ground always available at pin 5

The rest of the pins are available for serial data communications to the vehicle system. The serial data circuits are the means by which the microprocessor-controlled modules in the vehicle communicate with each other and the scan tool. There are 2 different types of protocols on this vehicle

1. The Universal Asynchronous Receiver Transmitter (UART)
2. Keyword 2000 Data line

The scan tool accesses the following module data lines

1. The electronic brake control module (EBCM) (UART)
2. The engine control module (ECM) (Keyword 2000)
3. The transmission control module (TCM) (UART)
4. The inflatable restraint sensing and diagnostic module (SDM) (UART)
5. The immobilizer control module (UART)
6. The anti-theft module (UART)

UART Data line

UART-Based communication systems have a master of the serial data line and remote transceivers. The master controls the message traffic on the serial data line by polling all of the remotes (control modules). The master then waits for the proper response.

1. The UART serial data line: The UART serial data line allows the following components to communicate data with a scan tool: The electronic brake control module (EBCM) The transaxle control module (TCM) The inflatable restraint sensing and diagnostic module (SDM) The immobilizer control module The anti-theft module
2. The UART serial data line allows a scan tool to communicate with these modules for diagnosis and testing.

Keyword 2000 Data Line

The Keyword protocols utilize a single wire bi-directional data line between the module and the scan tool. The message structure is a request and response arrangement. Keyword 2000 is used for scan tool diagnostics only. The modules do not exchange data on these systems.

The keyword 2000 serial data line

1. The keyword 2000 serial data line allows the following to communicate with the scan tool: The engine control module.
2. The keyword 2000 serial data line allows a scan tool to communicate with this module for diagnosis and testing.

See also:
• DTC U2105 (European and N. American Emissions)
• Checking Aftermarket Accessories
• Testing for Intermittent Conditions and Poor Connections
• Defective Scan Tool Notice
• Diagnostic System Check - ABS
• Diagnostic Starting Point - Theft Deterrent
• Circuit Testing
• Wiring Repairs
• Connector Repairs
• Inflatable Restraint Sensing and Diagnostic Module Replacement
• Theft Deterrent Control Module Replacement
• Diagnostic System Check - SIR
• Symptoms - Data Link Communications
• Scan Tool Does Not Communicate with Component