Skip to content
Book on WhatsApp

P0600

Serial Communication Link

A general fault on a serial communication link - typically used by older single-wire diagnostic protocols (KWP2000, ISO 9141) before CAN became universal. ECU has lost or corrupted communication with another module.

  • Check engine light: Yes
  • Emissions related: No
  • Repair difficulty: medium

Symptoms

  • Check engine light on
  • Possible limp mode or no-start
  • Multiple follow-up faults across modules
  • Reset/relearn may be needed after repair

Common causes

Ordered by how often each turns out to be the cause.

  • Harness fault on bus lineCommon
  • Gateway module routing CAN messages incorrectlyLess likely
  • CAN terminating resistor (120 Ω) drifted out of specLess likely

Parts involved

  • Serial Communication Bus

P0600 is a generic OBD-II code defined by SAE J2012. Exact wording and diagnostic procedure vary by manufacturer and model. Code definitions are drawn from the public-domain OBDex dataset; the workshop notes are our own.