Serial Communication Link Malfunction
The P0600 code means the vehicle's onboard diagnostic system has detected: Serial Communication Link Malfunction. This is a serious severity code.
- Keep driving?
- Yes, but fix soon
- DIY difficulty
- medium
- Estimated cost
- $100-$250 for battery; $200-$600+ for wiring or module diagnosis
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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.
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Scan all modules for additional codes. A failing module will often set codes in multiple systems.
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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.
Sources
This page is built from documented references. Verify against your own service info before repair work.
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