P0600 code: Meanings, Causes and Diagnosis

P0600 OBD2 Trouble Code is very rare. It indicates that there’s been a communications failure Between the ECM, one or more modules it communicates to.

Although P0600 can be found in all vehicles, it's most common to find it in older luxury cars like BMW, Audi and Mercedes. It can still be found on any car made after 1996.

Definition: P0600 Serial Communications Link

Modern vehicles have high speed data wiring that connects modules to their ECM. Every module controls a particular system.

The year of the vehicle, its make and model, as well as any options, will determine how many modules it has. As a rule, the newer the car or truck, the more modules it’ll have. Below are some common modules you could link with the ECM.

• The ignition system
• TCM
• Traction Control
• ABS
• VVT
• Transmission Control
• Cruise
• Lane Assistance/Road Departure
• Turbo Module
• Windows/Sunroof
• Airbags/Safety
• Body Control Module
• A/C

If any one of them is in contact with ECM, P0600 can be thrown and the check engine lights will flash.

P0600 Symptoms

The ECM module that lost communication will determine the symptoms of P0600.

For instance, if you have a transmission that isn’t shifting correctly, it’s fair to assume the transmission control module has lost communication. Airbag light? Check the module of your airbag.

P0600 Causes & Diagnosis

Check to make sure that P0600 is not being replaced by any codes. These codes can help you identify the problem module.

If you receive P0300 (an ignition-related code), you may be able to inspect the ignition module. P0700 indicates an issue with the transmission control module, and you’d want to look at the connection between it and the ECM.

If there are no other codes present, it’ll be tough to track down which module is causing the problem. When this is the situation (and even if it’s not), we recommend taking it to a mechanic with specialized diagnostic equipment to access the BUS system. These mechanics can quickly diagnose P0600.

The following conditions can be responsible for P0600.

1. Module connections

Verify the location where the module is connected to the wiring harness. Verify that all pins are free from corrosion and in excellent condition. In order to reach the ECM, module wiring often runs through several BUS junctions.

2. Ground

Both the ECM, data bus and particular module require a solid ground for operation. Check that everything is functioning properly.

3. Bad Module

The P0600 warning will be issued if the module isn't responsive or has failed. More common is a problem with the wiring than the module going bad.

Conclusion

The real problem with fixing P0600 at home is that everything is so hard to get to (under carpet, behind a panel, etc…) So we recommend taking it to a professional on this one (a very rare recommendation on this site).