What Does P0600 Mean?
P0600 indicates a malfunction in the serial communication link, which is the internal data bus the ECM/PCM uses to communicate with other control modules (TCM, ABS, BCM, etc.). This code means the PCM has detected a break or corruption in the CAN bus or other serial communication protocol. The driver may notice multiple warning lights illuminated, erratic gauge behavior, and potentially a no-start or limp mode condition.
Safety Warning
Do not drive the vehicle. A serial communication link failure can cause loss of critical safety systems including ABS, traction control, electronic power steering, and airbag deployment. Multiple systems may be inoperative or behave unpredictably. Tow to a repair facility.
Common Causes
35%
CAN bus wiring damage, open circuit, or short between CAN High and CAN Low lines
25%
Faulty ECM/PCM with internal communication processor failure
20%
Corroded or damaged CAN bus connectors or terminating resistors
15%
Failed or misbehaving module flooding the CAN bus with erroneous data
5%
Low battery voltage causing communication dropouts
Diagnostic Steps
1
Measure CAN bus voltages at the DLC (pins 6 and 14): CAN High should read approximately 2.5-3.5V and CAN Low approximately 1.5-2.5V with key on engine off. If both lines show the same voltage, there is a short between them.
2
Measure the terminating resistance between CAN High and CAN Low at the DLC — it should read approximately 60 ohms (two 120-ohm resistors in parallel). An open reading indicates a broken bus; 120 ohms indicates one terminating resistor is missing.
3
Use an oscilloscope to view CAN bus waveforms at the DLC. Normal CAN traffic should show clean, symmetrical differential signals. Look for noise, flat lines, or asymmetric waveforms indicating a faulty node.
4
Disconnect control modules one at a time while monitoring CAN bus signals to isolate a module that is pulling down or corrupting the bus.
5
Inspect all CAN bus wiring harness routing for chafing, pinching, or exposure to heat sources. Pay special attention near the steering column, transmission tunnel, and engine bay pass-through.
Estimated Repair Cost
$150 - $1,500
Parts + labor, varies by vehicle and location
P0600 indicates a malfunction in the serial communication link, which is the internal data bus the ECM/PCM uses to communicate with other control modules (TCM, ABS, BCM, etc.). This code means the PCM has detected a break or corruption in the CAN bus or other serial communication protocol. The drive...
The most common cause of P0600 (Serial Communication Link Malfunction) is: CAN bus wiring damage, open circuit, or short between CAN High and CAN Low lines
Typical repair costs for P0600 range from $150 to $1,500, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Do not drive the vehicle. A serial communication link failure can cause loss of critical safety systems including ABS, traction control, electronic power steering, and airbag deployment. Multiple systems may be inoperative or behave unpredictably. Tow to a repair facility.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P0600 to identify the root cause.
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Quick Info
Category
Powertrain
System
Vehicle Communication Network
Difficulty
Type
Generic (SAE)
Recommended Tools
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