What this code means
P0601 on this vehicle may indicate an internal memory checksum problem in the RFA module used by the passive anti-theft system with Phone as a Key.
What the vehicle may do
- The vehicle may have passive anti-theft, Phone as a Key, or remote function concerns.
- The code can also be present without an obvious driveability symptom.
Possible fault areas
- A possible fault area is the RFA module internal memory or control logic.
Diagnostic path
Open: what P0601 means here
On this F-150, P0601 is being handled as an RFA module internal control module memory checksum fault in the passive anti-theft system with Phone as a Key. In plain terms, the module may be failing its own internal memory check. The truck may have passive anti-theft, phone-as-a-key, or remote function symptoms, or the code may show up during a scan without an obvious customer complaint. For this fault path, the possible fault area is narrow: the RFA module itself. Still, start with the basic system checks and follow a structured diagnostic approach so you are not replacing a module based on an old or incidental code.
Clear the RFA codes first
Begin with the scan tool and clear all Diagnostic Trouble Codes from the RFA module. That first step matters because this test is looking for a code that comes back during the module self-test, not just a code that was sitting in memory from an earlier event.
Run the RFA self-test
Next, run the RFA module self-test with the scan tool. Let the module make the decision. This fault sets when the RFA module fails its internal checksum test, so the self-test result is the key piece of diagnostic information in this path.
Decide based on what returns
After the self-test, check whether the target internal module memory fault, or the related internal RFA module fault group used by this test, is present again. If one of those faults is present, check OASIS for any applicable TSB, GSB, SSM, or FSA. If one applies to this exact concern, stop this test and follow that path. If nothing applies to the concern, the directed repair is to install a new RFA module.
If the fault does not return
If the fault is not present after clearing codes and running the RFA module self-test, the system is operating correctly at this time. Do not force a repair out of this path when the module self-test does not bring the fault back.
Takeaway
The clean way through P0601 on this system is simple: clear the RFA codes, run the RFA self-test, and only act on the fault if it returns in that test path. If it does return, check for an applicable TSB, GSB, SSM, or FSA first; if none applies, the path points to the RFA module. For more diagnostic training, visit stepdiagnostics.com.
Final check
For this path, the diagnosis depends on whether the RFA module fault returns after clearing codes and running the RFA self-test.
For more guided automotive diagnostics, visit STEP Diagnostics.
