Code Definition

U1321 — Low speed can bus data instrument cluster communication intermittent

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

About U1321

U1321 is a manufacturer-specific network communication diagnostic trouble code recorded for Subaru vehicles. It belongs to the U-prefix family of codes, which covers inter-module network communication (CAN, LIN, FlexRay, or similar) faults.

When U1321 is stored, the module has detected a signal or supply voltage lower than the expected operating range.

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.

U1321 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.

Quick Facts

Code	U1321
System	Network Communication
Type	Manufacturer-Specific
Make	Subaru
Causes	—
Diag. Assistant	—
Video	—