Error Code P064F is defined as Unauthorized Software/Calibration Detected. This is a generic trouble code, meaning it applies to all vehicles equipped with the OBD-II system, particularly those made since 1996 up to present. This includes models from Acura, Audi, Buick, Cadillac, Chevrolet, Chrysler, Ford, Jaguar, Kia, Nissan, Scion, Toyota, etc. Specifications on the definition, troubleshooting, and repairs, of course, vary from make, model, and powertrain configuration.

When Error Code P064F is stored, this means the PCM (powertrain control module, also known as ECM or engine control module in other vehicle makes) has determined an unauthorized or unrecognized software application or controller calibration error.

Factory software installation and calibration of onboard controllers are both referred to as programming. Most programming is done before the vehicle is delivered to the owner, onboard controllers continue to adapt and learn in specific circumstances to meet the needs of the individual driver and their geographical locations (among other things). These factors include excessive temperature, voltage spikes, and excessive moisture, which may contribute to calibration and software failure.

This is why installing aftermarket software programs can result in Error Code P064F. This, however, is usually temporary, because as soon as the PCM learns the software, the code will be cleared and usually doesn’t reset.

Every time the ignition is turned on, and the PCM is energized, the self-test for the HO2S will initiate. Aside from running internal controller self-test, the CAN (controller area network) carries serial data from each module to make sure the onboard controllers are interfacing correctly. These tests are simultaneously performed.

If the PCM determines a problem in monitoring the controller software/calibration, then it will register the Error Code P064F and activate the malfunction light.

Common Symptoms

  • Delayed or no start condition
  • Engine drivability and performance issues

Other codes may be stored as well together with Error Code P064F.

Possible Causes

Common causes for this code include:

  • Programming error in the PCM
  • Faulty error or PCM
  • Installation of high performance or aftermarket software

How to Check

This code is quite a challenging problem to diagnose, and many times, it involves reprogramming issues. Thus, without the right tools and reprogramming equipment, it will be impossible to replace a defective controller and complete the repair.

When trying to diagnose this code, refer to your information source or TSB (technical service bulletin); looks for signs and symptoms parallel to the stored code. Search for the year, make, model, and engine of your vehicle. If you are able to find the right TSB, then you may get the best diagnostic information for your problem.

The first step is to connect the scanner to the vehicle diagnostic port and retrieve all stored codes, including their freeze frame data. You need to write down this information, just in case the problem proves to be intermittent. After writing down all pertinent information, clear the codes and then take the vehicle for a test drive to see if the code resets, or if the PCM enters readiness mode. If the PCM does the latter, then you have an intermittent problem, which is more difficult to diagnose, as it means you would have to wait for the problem to develop more before you can successfully diagnose.

However, if the code does NOT reset and there are the vehicle shows no drivability and engine performance issues, then the vehicle can be operated normally.

How to Fix

Depending on the diagnosis, common repairs for this code include:

  • Reprogramming of PCM
  • Repair or replacement of PCM

It’s important to test the integrity of the controller ground by connecting its negative test lead of the DVOM to ground, and a positive test lead to the battery voltage.