Serial Communication Link Malfunction
What does P0600 mean?
The P0600 code means the vehicle's onboard diagnostic system has detected: Serial Communication Link Malfunction. This is a serious severity code.
Common Symptoms
- Multiple warning lights on dashboard
- Communication errors between control modules
- Various system malfunctions (transmission, ABS, body control)
- Vehicle may enter limp mode
Probable Causes (Ranked by Likelihood)
- Low system voltage causing CAN bus communication errors High
- Damaged CAN bus wiring or connector High
- Faulty control module dragging down the CAN bus Moderate
- Corroded ground connections affecting module communication Moderate
Step-by-Step Diagnostic Procedure
-
Check battery voltage and charging system first -- low voltage is the most common cause of serial communication errors.
-
Inspect CAN bus connectors and wiring under the hood and at the data link connector (OBD-II port) for damage.
-
Scan all modules for additional codes. A failing module will often set codes in multiple systems.
-
Test CAN bus resistance between pins 6 and 14 of the OBD-II port: should be approximately 60 ohms (two 120-ohm terminating resistors in parallel).
Frequently Asked Questions
Can a bad battery cause P0600?
Yes. Low or unstable voltage is a very common trigger for serial communication codes. Always check the battery and charging system before pursuing expensive module or wiring repairs.