P0600: Serial Communication Link

What it means

A fault has been detected in a serial communication link. The code does not identify the particular link or explain whether the cause is in wiring, a module, or another part of the communication path.

At a glance

• Usually lights the check-engine light

How it works

Vehicle control modules exchange information over serial communication links, which may include network wiring and gateway routing between modules. P0600 indicates a detected fault on a serial link but does not name the affected link or establish whether the cause is wiring, a module, or another part of the communication path.

Common causes

Most likely first.

1. Harness fault on bus line
2. Gateway module routing CAN messages incorrectly
3. CAN terminating resistor (120 Ω) drifted out of spec

Symptoms

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

How to diagnose it

1. Record freeze-frame data and run a full-module scan to identify which modules are offline and whether other communication codes share the same network.
2. Check battery condition and module power and ground connections, since low voltage or a poor ground can disrupt several communication links.
3. Inspect accessible network wiring, connectors, and gateway connections for damage, corrosion, looseness, or recent repair disturbance.
4. Use the vehicle wiring diagram and service information to test the suspected network segment for continuity, shorts, and termination condition against the manufacturer's specification.
5. If the network wiring and supplies are sound, isolate the affected modules or gateway using the vehicle's communication diagnostic procedure.

Common fixes

• Repair a damaged or loose communication-bus connector.
• Repair an open, shorted, or corroded network wire in the affected segment.
• Correct a module power or ground fault causing communication loss.
• Repair or replace a faulty gateway or control module only after confirming the network wiring and module supplies are correct.

Can I keep driving?

Driving safety depends on which modules and functions have lost communication; multiple warnings, limp mode, or a no-start can occur. Avoid driving if braking, steering, stability control, or other essential functions are affected, and arrange prompt diagnosis if several module warnings appear.