If an error message is received or the scan tool does not support this function, disconnecting the battery ground
cable for a minimum of 5 minutes may be used as an alternative procedure.
FLASH ELECTRICALLY ERASEABLE PROGRAMMABLE READ ONLY MEMORY (FLASH
EEPROM)
Description
Flash Electrically Eraseable Programmable Read Only Memory (EEPROM) is contained in an Integrated
Circuit (IC) internal to the 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. The VID block
must be programmed when replacing the PCM as described under Programming the VID Block for a
Replacement PCM. Failure to perform this procedure may generate fault codes: P1635, P1639, VID Block not
programmed or is corrupt. The VID block in an existing PCM can also be tailored to accommodate various
hardware/parameter changes made to the vehicle since production. Failure to perform this procedure properly
may generate fault code: P1635, Tire/Axle Ratio out of Acceptable Range is one of the main causes for code:
P1639. This is described under Making Changes to the VID Block and also under Making Changes to the PCM
Calibration. The VID block contains many items used by the strategy for a variety of functions. Some of these
items include the VIN number, octane adjust, fuel octane, fuel type, vehicle speed limit, tire size, axle ratio, the
presence of speed control and four wheel drive electronic shift on the fly versus instruction shift on the fly. Only
items applicable to vehicle hardware and supported by the VID block will be displayed on the scan tool.
When changing items in the VID block, the strategy will place 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 will display a message indicating the need to flash the PCM again to reset the VID block.
The following procedures use the Worldwide Diagnostic System (WDS) for reprogramming:
z
PROGRAMMING VID BLOCK FOR REPLACEMENT PCM
z
MAKING CHANGES TO THE VID BLOCK
z
MAKING CHANGES TO THE PCM CALIBRATION
Reprogramming can be performed by a local Ford dealer for any non Ford facility. There are other Enhanced
Scan Tools that may have reprogramming capabilities available. Refer to the manufacturers users instruction for
details.
Programming VID Block For Replacement PCM
A new PCM will contain the latest strategy and calibration level for a particular vehicle. However, the VID
block will be blank and will need 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 instruction data entry into the new PCM.
Automatic data transfer will be performed 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 has been replaced.
2003 Ford Pickup F150
2003 ENGINE PERFORMANCE Self-Diagnostics - Bi-Fuel - Gasoline/CNG