Technical Description of OBD-II Trouble Code
Error in Internal Control Module EEPROM
What does that signify?
This is a generic diagnostic trouble code (DTC) for powertrain and is commonly found in OBD-II vehicles. This can include vehicles from various manufacturers such as Buick, Chevy, GMC, Ford, Toyota, Nissan, Mercedes, Honda, Cadillac, Suzuki, Subaru, etc. Although it is a generic code, the specific repair steps may vary depending on the year, make, model, and powertrain configuration of the vehicle.
When the code P062F is stored, it indicates that the powertrain control module (PCM) has detected an internal performance error with the electronically erasable read-only memory (EEPROM). Other controllers may also detect an internal PCM performance error in the EEPROM, leading to the storage of code P062F.
The internal control module monitoring processors are responsible for various self-test duties and overall accountability of the internal control module. The PCM and other related controllers constantly monitor the self-test and input/output signals of the EEPROM. The EEPROM also interacts with the transmission control module (TCM), traction control module (TCSM), and other controllers.
In automotive applications, the EEPROM allows for reading, erasing, and rewriting small amounts of programmable memory. The EEPROM, usually removable, is locked into a specially designed socket inside the PCM. When replacing a defective PCM, the EEPROM is typically removed and reused in the new PCM. The EEPROM and new PCM need to be programmed together as a unit. While the EEPROM is designed to last for hundreds of years and can handle more than 1 million programming changes, it can be sensitive to excessive heat and moisture.
Whenever the ignition is on and the PCM is energized, EEPROM self-tests are initiated. In addition to running internal controller self-tests, the controller area network (CAN) compares signals from each individual module to ensure proper functioning of each controller. These tests are performed simultaneously.
If the PCM detects discrepancies in EEPROM functionality or an internal EEPROM error between any of the on-board controllers, it will store the code P062F and may illuminate the malfunction indicator lamp (MIL). The MIL may require multiple failure cycles to illuminate, depending on the perceived severity of the malfunction.
Photo of a PCM with the cover removed:
What is the severity of this DTC?
Codes related to internal control module processors should be considered severe as they can result in various drivability concerns.
What are some of the symptoms of the code?
Symptoms of a P062F trouble code may include:
What are some of the common causes of the code?
Causes for this P062F DTC code may include:
What are some P062F troubleshooting steps?
Diagnosing a code P062F can be challenging, even for experienced technicians. Reprogramming equipment is necessary to replace a defective controller and complete a successful repair.
If there are ECM/PCM power supply codes present, they should be addressed before attempting to diagnose a P062F.
Preliminary tests can be performed before determining if an individual controller is defective. A diagnostic scanner, a digital volt/ohmmeter (DVOM), and reliable vehicle information are required.
Connect the scanner to the vehicle diagnostic port and retrieve all stored codes and freeze frame data. Record this information in case the code is intermittent. After recording the information, clear the codes and test drive the vehicle until the code is reset or the PCM enters readiness mode. If the PCM enters readiness mode, the code is intermittent and more difficult to diagnose. If the code is reset, continue with the following preliminary tests.
When diagnosing a P062F, information is crucial. Search for technical service bulletins (TSB) that match the stored code, vehicle information (year, make, model, and engine), and exhibited symptoms. The right TSB may provide diagnostic information that can greatly assist in the diagnosis.
Use the vehicle information source to obtain connector face views, connector pin-out charts, component locators, wiring diagrams, and diagnostic flow charts related to the code and vehicle in question.
Use the DVOM to test controller power supply fuses and relays. Replace blown fuses as necessary, testing them with the circuit loaded.
If all fuses and relays appear to be functioning properly, visually inspect the controller-related wiring and harnesses. Check chassis and engine ground junctions. Use the vehicle information source to locate ground locations for related circuits and test ground integrity using the DVOM.
Visually inspect system controllers for signs of water, heat, or collision damage. Any damaged controller, especially due to water, should be considered defective.
If the controller power and ground circuits are intact, suspect a defective controller or a controller programming error. Controller replacement will require reprogramming. Aftermarket sources may offer reprogrammed controllers for some vehicles, while others may require on-board reprogramming that can only be done through a dealership or qualified source.
