Scan Tool Does Not Communicate with CAN Device

SCAN TOOL DOES NOT COMMUNICATE WITH CAN DEVICE

CIRCUIT DESCRIPTION
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:
- Identifying the stored diagnostic trouble codes (DTCs)
- Reading the serial data stream
- Clearing the DTCs
- Storing the Freeze Frame data

DIAGNOSTIC AIDS
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:
- Backed-out terminals
- Improper mating of terminals
- Broken electrical connector locks
- Improperly formed or damaged terminals
- Faulty terminal-to-wiring connections
- Physical damage to the wiring harness
- A broken conductor inside the wire insulation
- Corrosion of the electrical connections, the splices, or the terminals

TEST DESCRIPTION

Step 1 - Step 16:

Step 17 - Step 29:

The numbers below refer to the step numbers on the diagnostic table.
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.
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.
7. This step checks for a high resistance or an open/short in the ECM serial data circuit.
8. This step checks the ECM DLC Diagnostic circuit high resistance or open/short. This could cause the ECM not to communicate.
9. This step checks to see if the EBCM is not communicating with the scan tool.
14. This step checks to see if the SIR system is not communicating with the scan tool.
19. This step checks to see if the theft deterrent-immobilizer system is not communicating with the scan tool.