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Rock Sam

Rock Sam 8/14/2018

2008 Hummer H3 Base 5 Cyl 3.70L


How do I diagnose P0600 OBD-II Trouble Code of my car and what are its causes? What causes Serial Communication Link

1 Answer

PartsAvatar Ca

PartsAvatar Ca 8/14/2018

What the P0600 code means?

P0600 means that the ECU has lost the connection with one of its many controllers more than once. When this code is set the ECU triggers the Check Engine Light to be displayed on the dashboard and a fail safe mode enacted. The fail safe mode is to prevent further damage and protect the vehicle. Fail safe mode will remain in effect until the normal operation is detected or the vehicle is repaired.

What causes the P0600 code?

Experience has proven that a poor connection or failed ECM driver is the root cause of this code. For the most part, the ECM acts as a ground to control these components and modules as opposed to supplying power to them. A loose or corroded connector is more likely than a frayed or broken wire between both devices. Poor grounds are another plausible cause. The ECM, as well as the activator module, need a good ground to operate.

What are the symptoms of the P0600 code?

Symptoms may include drivability issues, harsh shifting, decreased fuel economy, the engine may stall or run roughly at idle, poor acceleration, a stored trouble code, and possibly an illuminated service engine soon lamp. If this code is stored, and a service engine soon lamp has not yet been illuminated, the code may be shown as pending.

Common mistakes when diagnosing the P0600 code:

Symptoms and stored codes that are present as a reaction to a communication failure are often misdiagnosed and repaired as the cause of the problem. Obviously, this leads to an unsuccessful repair. Engine misfire codes, lean exhaust codes, fuel injector codes, and virtually any other drivability or transmission code that is accompanied by a controller communication code can potentially be a pitfall for misdiagnosis. Follow the rule that says to diagnose codes in the order in which they are stored and you will improve your chances for a successful diagnosis. Utilize freeze frame data to help you determine which codes were stored first.

What repairs can fix the P0600 code?

1. ECU replacement.

2. Diagnosing and repairing the cause of the low battery voltage.

3. Repairing or replacing the ECU wiring harness.

4. Fixing poor electrical connections.


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