Communications Network

Communications Network

Inspection and Verification

1. Verify the customer concern.

2. Visually inspect for obvious signs of electrical damage.
- If an obvious cause for an observed or reported concern is found, correct the cause (if possible) before proceeding to the next step.


Visual Inspection Chart






3. Connect the scan tool to the DLC (Data Link Connector).

- NOTE: Make sure to use the latest scan tool software release.

NOTE: The Vehicle Communication Module (VCM) LED prove-out confirms power and ground from the DLC (Data Link Connector) are provided to the VCM (Vehicle Communication Module).

If the Integrated Diagnostic System (IDS) does not communicate with the VCM (Vehicle Communication Module) :
- Check the VCM (Vehicle Communication Module) connection to the vehicle.

- Check the scan tool connection to the VCM (Vehicle Communication Module).

- GO to Pinpoint Test AE, to diagnose No Power To The Scan Tool Pinpoint Test AE: No Infotainment Controller Area Network (I-CAN) Communication, All Modules Are Not Responding.

4. Establish a scan tool session.

- NOTE: The scan tool first attempts to communicate with the PCM. After establishing communication with the PCM, the scan tool then attempts to communicate with all other modules on the vehicle.

If an IDS (Integrated Diagnostic System) session cannot be established with the vehicle, (IDS (Integrated Diagnostic System) may state "No communication can be established with the PCM"):

- Choose "NO" when the scan tool prompts whether or not to retry communication.

- Enter either a PCM part number, tear tag or calibration number to identify the vehicle and start a session. The PCM part number and 4-character tear tag are printed on the PCM label. If the PCM part number cannot be found, a base part number search on the HVBOM application (under the OASIS (On-Line Automotive Service Information System) tab on the technician service publication website) retrieves the PCM part number.

- GO to Pinpoint Test A, to diagnose The PCM Does Not Respond To The Scan Tool Pinpoint Test A: The PCM Does Not Respond To The Scan Tool.

5. Carry out the network test.
- If the network test passes, retrieve and record the continuous memory DTCs and proceed to Step 6.

- If the network test fails, GO to Symptom Chart to diagnose the failed communication network Symptom Related Diagnostic Procedures.

- If a module fails to communicate during the network test, GO to Symptom Chart Symptom Related Diagnostic Procedures.

6. Retrieve and review the DTCs.
- If the DTCs retrieved are related to the concern, go to DTC Charts Communications Network. Follow the non-network DTC diagnostics (B-codes, C-codes, P-codes) prior to the network DTC diagnostics (U-codes).

- If no DTCs related to the concern are retrieved, GO to Symptom Chart Symptom Related Diagnostic Procedures.