U1961 – Lost Communication with the Hybrid Powertrain Control Module (HPCM).

The ODBII code U1961 indicates that there is a communication failure between the vehicle’s onboard computer and the Hybrid Powertrain Control Module (HPCM), which may affect the operation of the hybrid system.

The severity of ODBII code U1961 is generally considered moderate to high.

Common Causes For: U1960 Lost Communication with the Body Control Module (BCM).

• Faulty Hybrid Powertrain Control Module (HPCM)
• Damaged or corroded wiring or connectors
• Poor ground connections
• Failed communication network (CAN bus issues)
• Malfunctioning sensors related to the hybrid system
• Software or firmware issues in the HPCM
• Battery management system faults
• Issues with the vehicle’s main power supply or battery
• Interference from aftermarket modifications or devices

Common misdiagnosis for U1961 Lost Communication with the Hybrid Powertrain Control Module (HPCM)”.

• Faulty Hybrid Powertrain Control Module (HPCM)
• Wiring issues or damaged connectors
• Faulty Engine Control Module (ECM)
• Battery management system problems
• Communication network issues (CAN bus)
• Faulty sensors related to the hybrid system
• Software or firmware issues in the control modules
• Grounding issues in the electrical system

Common Troubleshooting Steps

When dealing with the OBD-II code U1961, which indicates “Lost Communication with the Hybrid Powertrain Control Module (HPCM),” there are several common troubleshooting steps you can follow to diagnose and potentially resolve the issue. Here’s a structured approach:

• Check for Other Codes: Use an OBD-II scanner to check for any additional trouble codes. Other codes may provide more context or indicate related issues.
• Inspect the Wiring and Connectors: **Visual Inspection: Check the wiring harness and connectors related to the HPCM for any signs of damage, corrosion, or loose connections.
• **Connector Pins: Ensure that the pins in the connectors are not bent, corroded, or damaged.
• Check the HPCM Power and Ground: **Power Supply: Verify that the HPCM is receiving the correct voltage. Use a multimeter to check the power supply to the module.
• **Ground Connections: Ensure that the ground connections for the HPCM are secure and free of corrosion.
• Inspect the Communication Network: **CAN Bus: Check the Controller Area Network (CAN) bus for continuity and proper operation. Look for any shorts or opens in the wiring.
• **Termination Resistors: Ensure that the CAN bus has the correct termination resistors in place and that they are functioning properly.
• Test the HPCM: If possible, perform a functional test of the HPCM using a scan tool. This may involve checking for communication with other modules.
• If the HPCM is suspected to be faulty, consider replacing it or testing it in another vehicle if available.
• Check for Software Updates: Verify if there are any software updates available for the HPCM or the vehicle’s ECU. Sometimes, communication issues can be resolved with a software update.
• Inspect Related Components: Check other components that may interact with the HPCM, such as the battery, inverter, and other hybrid system components, for any faults.
• Clear Codes and Test Drive: After performing the above checks and repairs, clear the trouble codes and take the vehicle for a test drive to see if the code returns.
• Consult Technical Service Bulletins (TSBs): Look for any TSBs related to the specific make and model of the vehicle. Manufacturers may have issued guidance on common issues related to the HPCM.
• Seek Professional Help: If the issue persists after performing these steps, it may be necessary to consult a professional mechanic or a dealership with experience in hybrid vehicles. By following these steps, you can systematically diagnose and address the U1961 code. Always ensure safety precautions are taken, especially when working with hybrid vehicles, as they contain high-voltage components.