P064F code meaning
Unauthorized Software/Calibration Detected
Powertrain system Generic code P06xx codes Check engine light
What P064F means
P064F means the module has found that its software or calibration is not the version released by the manufacturer, or fails an authenticity check (signature, checksum, security keys). CARB requires manufacturers to protect calibrations against changes without special tools and to report calibration IDs and checksums. GM's 2025 engine modules set it when the embedded message authentication table for secured bus messages is invalid, with the lamp in the first trip; chassis modules also check missing key storage or wrong key-slot configuration. Chrysler fixed P064F on the 2017 Ram 3500–5500 chassis cab 6.7 L Cummins by reprogramming – so it is not only about tuning. Typical triggers are tuning software, an interrupted or wrong reflash, a module from another vehicle, or a module replaced without learning its security keys. Programming released software usually clears it.
P064F at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modeNot expected
- Repair difficultyMedium
- Typical labor0.5 to 2 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P064F
- Check engine light (GM in the first trip)
- Possibly follow-up codes in other modules or communication problems
- Driving often normal
Common causes of P064F
- Most likelyUnapproved or tuned software (chip tuning, programmer)
- PossibleFaulty or interrupted reflash, outdated software
- PossibleUsed or replaced module without learning the security keys, wrong configuration
- Less likelyModule faulty internally (key storage)
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Engine control moduleControl module software
What each part of P064F means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 6 | Area: computer (engine control module) and output circuits. |
| 4F | The exact fault in that area. |
What to do next
- Note P064F and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P064F
What does P064F mean?
P064F means "Unauthorized Software/Calibration Detected". P064F means the module has found that its software or calibration is not the version released by the manufacturer, or fails an authenticity check (signature, checksum, security keys). It is a generic code, so it means the same on every make.
Is it safe to drive with P064F?
Usually yes, for a short time, if the check engine light is steady and the car drives normally. If the light flashes or the car runs badly, stop and have it checked.
Will P064F fail an emissions test?
Yes, it can. P064F is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P064F to fix?
Difficulty: medium. A typical repair takes 0.5 to 2 hours of work. This is a job for a workshop.
Will P064F clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.