P0600Generic code

P0600 Code: Serial Communication Link Malfunction

The P0600 code means the engine computer cannot communicate internally or with another module over a dedicated data line. Check the power supply and grounds before you replace the computer.

Severity
Medium
Can I keep driving?
Yes, but with caution
Estimated cost
$0 to $1,500
Difficulty
Hard
System
Computer and Outputs
Applies to
All OBD2 vehicles

Updated Reviewed by Renzo Chacca

On this page

What the P0600 code means

Some computers have several processors, or they talk to another module (for example, the transmission computer) over their own serial line. The P0600 code means that communication is failing.

Before you decide the computer is bad, always check its power supply and grounds. Low voltage, a loose terminal or a corroded ground cause internal errors that go away once they are corrected. It is also worth looking for software updates from the manufacturer, because many of these codes are resolved by reprogramming the computer without replacing it.

If the computer has to be replaced, keep in mind that it almost always needs programming: VIN, immobilizer, option configuration and, on many vehicles, relearn procedures afterward. A used computer that has not been programmed can leave the vehicle unable to start.

P0600 code symptoms

  • Check engine light on.
  • The engine may not start or may run in limp mode.
  • Other codes at the same time in several systems.

Likely causes of the P0600 code

  1. Computer power supply or ground: low voltage or a connection with resistance.
  2. Battery disconnected or discharged, especially for P0603.
  3. Software with bugs. Manufacturer updates exist.
  4. Moisture or corrosion inside the computer from deteriorated case seals or water getting in through the engine bay.
  5. Internal failure of the computer. Only after you rule out everything above.

How to diagnose the P0600 code step by step

  1. Clear the code and see whether it comes back. Some are caused by a one-time event, such as a discharged battery.
  2. Measure the voltage at the computer power pins and compare it with the battery.
  3. Measure the voltage drop on the grounds. It should be under 0.1 V with a load.
  4. Look for technical service bulletins and software updates.
  5. Inspect the computer connector for moisture, corrosion or bent pins.

How to fix the P0600 code

  • Correct the power supply and the grounds.
  • Reprogram or update the computer.
  • Replace the computer only if everything above is good, and program it.
  • Clear the codes and verify.

Technical reference data

  • Supply voltage: battery voltage, with less than 0.2 V of drop.
  • Programming needs a stable voltage, so use a battery maintainer.
  • Reference values only: check the manufacturer data for your vehicle.

Brand-specific notes

Manufacturers publish software updates that fix many of these codes. Check with the dealer before you replace the computer.

P0600 on Ford

Software updates have fixed related codes such as P0606 on Ford vehicles.

P0600 on Chrysler

Software updates have fixed related codes such as P0606 on Chrysler vehicles.

P0600 on Hyundai

Software updates have fixed related codes such as P0606 on Hyundai vehicles.

Frequently asked questions about P0600

Can I drive with the P0600 code?
It depends on the symptoms. If the engine runs normally, drive with caution. If it goes into limp mode, take the vehicle to a shop.
Does the computer have to be replaced?
Not always. Many times it is the power supply, a ground or the software.
Does a used computer work?
Only if it is programmed correctly for your vehicle.
How much does it cost to fix P0600?
From $0 (if it was the battery) up to $1,500 if the computer has to be replaced and programmed.
What does the P0600 code mean?
The P0600 code is a generic OBD2 code for a serial communication link malfunction. The computer cannot communicate internally or with another module over its dedicated data line.
What is the most common cause of P0600?
Low voltage or a bad ground at the computer, followed by software that needs an update.

Related codes

Questions about the P0600 code

There are no questions about this code yet. Tell us about your case: vehicle, symptoms and what you have already checked.