P1637 Can Link ECM/ABSCM Circuit / Network Malfunction

Definition

Common causes

• Faulty ECM (Engine Control Module)
• Faulty ABSCM (Anti-lock Brake System Control Module)
• Damaged wiring or connectors in the communication circuit
• Poor ground connections
• Corroded or loose connectors
• Faulty CAN bus communication
• Software issues or programming errors in the ECM or ABSCM
• Malfunctioning sensors affecting communication
• Intermittent electrical issues or shorts in the circuit

Common misdiagnoses

• Faulty ABS module
• Faulty ECM (Engine Control Module)
• Wiring issues or shorts in the circuit
• Poor ground connections
• Corroded connectors
• Faulty wheel speed sensors
• Incorrectly programmed or updated software
• Battery or charging system issues
• Faulty ignition switch
• Intermittent electrical connections

Troubleshooting steps

1. 1. Check for Additional Codes

   Use an OBD-II scanner to check for any other trouble codes that may be present. This can provide more context for the issue

2. 2. Inspect Wiring and Connectors

   Visual Inspection: Check the wiring harness and connectors between the ECM and ABSCM for any signs of damage, corrosion, or loose connections

3. 3. Repair or Replace

   If any damaged wires or connectors are found, repair or replace them as necessary

4. 4. Check Power and Ground

   Power Supply: Ensure that the ECM and ABSCM are receiving the correct voltage. Use a multimeter to check the power supply to both modules

5. 5. Ground Connections

   Verify that the ground connections for both modules are secure and free of corrosion

6. 6. Test Communication

   Scan Tool Communication: Use a scan tool to check if you can communicate with both the ECM and ABSCM. If one module is unresponsive, it may indicate a failure in that module

7. 7. Network Testing

   If possible, use a scope to check the communication lines (CAN bus) for proper signals

8. 8. Check for Short Circuits

   Inspect the wiring for any short circuits that may be affecting communication between the ECM and ABSCM

9. 9. Inspect for Intermittent Issues

   Sometimes, the issue may be intermittent. Pay attention to any patterns, such as specific driving conditions or environmental factors that may trigger the code

10. 10. Update Software/Firmware

    Check if there are any software updates available for the ECM or ABSCM. Sometimes, manufacturers release updates to fix known communication issues

11. 11. Replace Faulty Components

    If all other steps have been checked and the issue persists, consider replacing the ECM or ABSCM, as one of them may be faulty

12. 12. Clear Codes and Test Drive

    After performing repairs, clear the trouble codes and take the vehicle for a test drive to see if the code returns

13. 13. Consult Technical Service Bulletins (TSBs)

    Check for any TSBs related to the P1637 code for your specific vehicle make and model. Manufacturers may have specific recommendations or known issues.1

14. 14. Seek Professional Help

    If you are unable to resolve the issue, consider seeking help from a professional mechanic or automotive technician who has experience with OBD-II diagnostics. By following these steps, you should be able to identify and resolve the underlying issue causing the P1637 code