What this code means
U0131 may mean the PCM is not receiving a valid communication message from the EPS control unit over the vehicle network.
What the vehicle may do
- The vehicle may show steering-related warning indicators.
- The vehicle may have communication-related symptoms or additional network codes.
- Power steering behavior may be affected depending on the fault and vehicle state.
Possible fault areas
- Possible EPS control unit power or ground concern.
- Possible EPS control unit startup concern.
- Possible PF-CAN communication concern between the PCM, EPS control unit, and gateway side of the network.
Diagnostic path
Opening context
On this 2016 through 2024 Honda Civic with the 2.0L engine, U0131 is a lost-communication type code between the PCM and the EPS control unit over the PF-CAN line. In plain terms, the powertrain side may not be getting a valid message from the electric power steering module. The vehicle may show steering-related warnings, communication faults, or other network symptoms, depending on what else is happening on the car. The broad areas to keep in mind are possible EPS control unit power or ground issues, the EPS control unit not starting up normally, or a CAN communication problem between the modules.
How the code sets
The logic for this code is straightforward: if the PCM cannot receive the EPS control unit signal over the PF-CAN line, or if the information coming from the EPS control unit is abnormal for the required cycle, the PCM treats that as a fault and stores U0131. So before chasing the network too far, think about whether the EPS module is actually waking up and being powered correctly.
Start the diagnostic path
Start with the basic system checks and follow a structured diagnostic approach. If other codes are present, check what they mean first, especially anything that could explain why the EPS control unit is not powered up, not grounded, or not communicating.
Check EPS power and ground first
Before getting deep into CAN diagnosis, check the power and ground circuit for the EPS control unit first. That matters here because this code may store simply because the EPS control unit did not start normally, and a power or ground circuit failure is specifically called out as a possible reason.
Move into communication diagnosis
Once EPS power and ground have been addressed, continue with the lost-communication CAN diagnostic path between the affected bus connection and the gateway side of the network. Keep the focus on why the PCM is not receiving a normal EPS message over PF-CAN. If the path does not clearly bring you back to a known next step, pause, recheck the earlier diagnostic path, and avoid guessing.
Verification
For verification, turn the vehicle to ON mode and wait 6 seconds. Then confirm whether U0131 resets or stays gone. Keep this verification step separate from the circuit and communication testing, so you know whether the actual fault condition has returned.
Takeaway and CTA
The takeaway: U0131 is not a parts call by itself. Confirm the EPS control unit can power up correctly, then follow the communication path and verify the code after the ON-mode wait. For more diagnostic training, visit stepdiagnostics.com.
Final check
U0131 should be approached as a communication diagnosis, with EPS power and ground checked before deeper network testing.
For more guided automotive diagnostics, visit STEP Diagnostics.
