P077C, P077D, P077E, P077F ISO/SAE Reserved
What Is The Severity Of An ISO/SAE Reserved Trouble Code?
Conditions which contribute to an ISO/SAE code being stored can range from severe to irrelevant. This is one aspect which makes this code potentially frustrating.
Possible Symptoms
Symptoms of an "ISO/SAE Reserved" code may include:
Potential Causes For This Code
"ISO/SAE Reserved" Diagnostic Information
Unlike many other codes, when diagnosing an ISO/SAE code, the best that you can hope for are other stored codes. The codes and symptoms exhibited (and their severity) frequently play a critical role in a successful diagnosis of the ISO/SAE code.
Obviously, you will need to diagnose and repair any other stored codes before attempting to diagnose the ISO/SAE code.
Search applicable technical service bulletins (TSB) for entries which match the vehicle in question. Finding a TSB that parallels the symptoms, codes, and vehicle in question will help immensely in your diagnosis.
You will need to make sure that all corrosion is removed from the battery and battery cable ends, that the battery is fully charged, and the alternator is charging adequately. A low voltage condition or a poor connection at the battery could contribute to an ISO/SAE code being stored.
In my own professional experience, I have (several times) discovered that rodent damage was at the root of a CAN malfunction. I would begin my limited diagnosis with a visual inspection of all visible wiring and connectors. Make repairs as required.
After a thorough visual inspection, I would connect a scanner to the diagnostic port of the vehicle and retrieve all stored codes and freeze frame data. I like to write this information down as it may prove helpful as my diagnosis unfolds. Next, I would clear the codes and test-drive the vehicle in hopes that the ISO/SAE code was intermittent and was not reset. Operate the vehicle normally until the PCM enters readiness mode or the ISO/SAE code is reset.
If the ISO/SAE code is reset, and there are no helpful TSB entries, I would perform a wiggle test on all controller/CAN bus connectors.
Suspect a possible controller defect or a controller programing error if a wiggle test does not yield results.
ISO/SAE Reserved Code Examples
Some examples of ISO/SAE reserved diagnostic OBD-II trouble codes include: P011E, P011F, P012F, P015E, P015F, P016A-P016F, P017A-P017F, P019A-P01FF, P04AB-P04FF, P030A-P030F, P031A-P031F, P032F, P033F, P034A-P034F, P035A-P035F, P036A-P036F, P037A-P037C, P038A-P038F, P0395-P03FF, P0000, P00C0-P00FF, P052F, P053D-P053F, P054E, P054F, P055A-P055F, P056C-P056F, P057A-P057F, P058A-P058F, P059A-P05FF, P025E, P025F, P026A-P026F, P027A-P027F, P028A-P028F, P02FB-P02FF, etc.
NOTE: This information is presented for information purposes only. It is not intended as repair advice and we are not responsible for any actions you take on any vehicle. All information on this site is copyright protected.
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"Delete Error Code Permanently, Disable DTC Error Code Function for P077C, in the ECU"
In extreme cases, we even have the option to permanently remove the specific DTC P077C, and disable the function of the specific error code in the ECU. All other fault code functions will then continue to work to protect the engine. This is different from clearing an error code with a diagnostic device. We have the option to permanently remove the function of the specific error code, so that it never comes back. Also emergency running that occurs on the specific error code can be solved in most cases.
Of course we prefer to first try to solve the cause of the error code, but sometimes the only solution is to permanently disable the DTC function of P077C,.
