What this code means
P0601 may indicate a possible internal integrity problem in the engine or powertrain control module.
What the vehicle may do
- The vehicle may run normally with only a warning light.
- The vehicle may have possible driveability symptoms depending on module operation.
- The code can appear along with other control-module or power-related codes.
Possible fault areas
- Possible module programming or setup issue.
- Possible internal engine control module or powertrain control module fault.
- Possible weak battery, low system voltage, poor connection, B+ circuit issue, or ground issue.
Diagnostic path
Opening context
On this Silverado 2500 diesel, P0601 points toward a possible internal integrity problem in the engine or powertrain control module. The truck may run normally, may have a warning light, or may show driveability issues depending on what the module is seeing. Broadly, I’m thinking about possible module programming problems, possible internal module faults, and possible low-voltage or connection issues before I condemn anything. For this code, stay disciplined: start with the basic system checks, then follow a structured diagnostic approach instead of jumping straight to a module.
Monitor and setting logic
The monitor for P0601 is treated as a control-module integrity check. Once the ignition and start signal are on, the diagnostic runs continuously after the running conditions are met. The code sets when the control module sees an internal malfunction or a system programming malfunction. That is why the first part of the diagnosis sorts out programming-related codes and other module-related code groups before the P0601 power and ground check.
Initial code sorting
With the ignition on and the vehicle in service mode, first look for the programming and setup group of control-module codes. If one of those is present, complete the needed programming and setup for the engine control module or powertrain control module, then verify the code does not reset. If it does reset after that, the diagnostic path calls for replacing the engine control module or powertrain control module. If it does not reset, that branch is okay.
Continue through related module code groups
If that programming group is not set, move to the next internal-performance group. If one of those codes is present, the path calls for replacing the engine control module or powertrain control module. If that group is clear, check the power relay, ignition, and related control-module power code group. If one of those is present, check what that code means first before continuing with the P0601 branch.
P0601 branch testing
If those earlier groups are clear and P0601 is in the final internal-module group that is set, keep the ignition on with the vehicle in service mode. Watch the scan tool Battery Voltage parameter. The value should not spike or drop out. While watching that parameter, wiggle the harness and connectors at the engine control module or powertrain control module. Then do the same at the underhood fuse block. You are trying to catch an intermittent B+ or ground problem before calling the module bad.
Decision point
If Battery Voltage spikes or drops out during that check, repair the B+ circuit or ground as needed. If Battery Voltage does not spike or drop out, the diagnostic path calls for replacing the engine control module or powertrain control module. If P0601 is not set during this branch, the result is all okay for this path.
Verification and close
After the repair, keep verification separate from the testing. Verify the repair and confirm the code stays gone. If a control module was replaced, make sure the required programming and setup are completed as part of the repair process. The takeaway on P0601 is simple: sort the related module-code groups first, prove the module power and ground are stable, and only then follow the replacement path if the voltage signal stays clean. For more diagnostic training, visit stepdiagnostics.com.
Final check
P0601 is often approached by checking related module-code context first, then confirming stable module power and ground before making a module decision.
For more guided automotive diagnostics, visit STEP Diagnostics.
