Flash Electrically Erasable Programmable Read Only Memory (EEPROM)

FLASH ELECTRICALLY ERASABLE PROGRAMMABLE READ ONLY MEMORY (EEPROM)

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Description
Flash electrically erasable programmable read only memory (EEPROM) is contained in an integrated circuit internal to the powertrain control module (PCM). The EEPROM contains the vehicle strategy including calibration information specific to the vehicle and is capable of being reprogrammed or reflashed repeatedly.

As part of the calibration there is an area referred to as the vehicle identification (VID) block. Program the VID block when installing a new PCM as described under Programming the VID Block for a Replacement PCM. Failure to carry out this procedure may generate diagnostic trouble code (DTC) P1639, VID Block Not Programmed or is Corrupt. The VID block in an existing PCM can also be tailored to accommodate various hardware changes made to the vehicle since production. Failure to carry out this procedure correctly may generate DTC P1635, Tire/Axle Ratio out of Acceptable Range. The VID block contains many items used by the strategy for a variety of functions. Some of these items include the vehicle identification number (VIN), octane adjust, fuel octane, fuel type, vehicle speed limit, tire size, axle ratio, and the presence of speed control. Only items applicable to vehicle hardware and supported by the VID block are displayed on the scan tool.

When changing items in the VID block, the strategy places range limits on certain items such as tire and axle ratio. The VID block is also limited to the number of times to be reconfigured. When this limit is reached, the scan tool displays a message indicating the need to flash the PCM again to reset the VID block.

On selected vehicles equipped with permanent DTC reporting capabilities, neutral profile correction should be learned after a PCM replacement in order to activate the misfire monitor. This can be accomplished using the Misfire Monitor Neutral Profile Learn function on the scan tool.

Reprogramming can be carried out by a local Ford dealer or any non-Ford facility. Refer to the manufacturer's user manual for details.

Programming the VID Block for a Replacement PCM
The VID block on a replacement PCM is blank and requires programming. There are 2 procedures available. The first is an automatic data transfer from the old PCM to the new PCM and the second is manual data entry into the new PCM.

Automatic data transfer is carried out if the old PCM is capable of communicating. This is done by the use of a scan tool to retrieve data from the old PCM before removing it from the vehicle. The stored data can now be downloaded to the new PCM after it is replaced.

Carry out the Manual data entry if the old module is damaged and is incapable of communicating. Remove and install a new PCM. Using a compatible scan tool, select and carry out the Module/Parameter programming, referring to the manufacturer's user manual. Make certain that all parameters are included. Failure to correctly program tire size in revolutions per mile, (rev/mile equals 63,360 divided by the tire circumference in inches) or axle ratio, may result in DTCs P1635 and P1639. You may be instructed to contact the As Built data center for the information needed to manually update the VID block with the scan tool. Contact the center only if the old PCM cannot be used or the data is corrupt. For Ford and Lincoln technicians, contact the National Hotline or Professional Technician Society (PTS) website for As Built data. Non-Ford technicians, use the Motorcraft website at motorcraft.com. From the Motorcraft homepage, use the search function to find the Module Programming or As Built Data.

Making Changes to the VID Block
A PCM which is programmed may require changes to be made to certain VID information to accommodate vehicle hardware. Refer to PCM/Module Reprogramming on the scan tool.

PCM Reprogramming

NOTE: After the PCM is successfully reprogrammed, clear any TCM DTCs that may have been stored during reprogramming.

At certain times, the entire EEPROM needs to be completely reprogrammed. This is due to changes made to the strategy or calibration after production or the need to reset the VID block because it has reached its limit. Refer to PCM/Module Reprogramming on the scan tool.