Code Definition

U1003 — SCP (J1850) Invalid or Missing Data for Primary Id

System: Network Communication  |  Type: Manufacturer-Specific  |  Make: Ford

About U1003

U1003 is a manufacturer-specific network communication diagnostic trouble code recorded for Ford vehicles. It belongs to the U-prefix family of codes, which covers inter-module network communication (CAN, LIN, FlexRay, or similar) faults.

Scanning & clearing: Network (U) codes report communication faults between modules. When diagnosing U-codes, checking the vehicle's CAN bus integrity, supply/ground at each module, and reading all modules for related faults is usually the first step.

U1003 is a manufacturer-specific code. The same code string on a different make may have a different meaning. Always confirm the code's definition against the vehicle's service information for the specific make and model under test.

Code Information

The Standard Corporate Protocol (SCP) is the Ford J1850 communication network that links control modules on many Ford vehicles. Modules exchange data messages over the bus, and the Primary Id portion identifies the source or target module. DTC U1003 sets when a module receives a message with an invalid or missing Primary Id, or fails to receive the expected identifier from another module, indicating a communication fault on the SCP bus. It is closely related to the other SCP Primary Id codes and frequently sets alongside them. When this code is set the functions that rely on the shared data ma...

Join TaT to view the complete code information and diagnostic details.

Quick Facts