P0600 Serial Communication Link Malfunction

P0600 indicates a serial communication link malfunction. One or more control modules are not communicating as expected on the vehicle network.

Code details

Generic OBD-II · P0

System: Computer
Code type: Generic (SAE / ISO controlled)
Standard: SAE J2012 / ISO 15031-6

Diagnostic boundary

A diagnostic trouble code reports that a monitored test failed. It does not prove one specific part is bad, and manufacturer logic can add vehicle-specific conditions.

Do not replace the PCM from P0600 alone; network power, ground, wiring, and other modules must be checked first.

Symptoms of P0600

Check-engine light, sometimes with several unrelated codes at once.
Warning lights, a no-start, or intermittent electrical faults.
Communication or module-reset problems on a scan tool.

Common causes of P0600

Low battery voltage, poor grounds, corroded connectors, or blown fuses.
Wiring or network (CAN bus) faults between modules.
A module software/programming issue, or rarely a failed controller.

Useful checks before replacing parts

Scan all modules for communication codes and identify which modules are missing or reporting network faults.
Check battery voltage, grounds, network wiring, module connectors, terminating resistance, and aftermarket electronics.
Review whether the fault appears after repairs, water intrusion, low voltage, jump-starting, or module replacement.

Related OBD-II codes

These nearby computer entries can help compare wording and pin down the fault area.