C0800 Code: Control Module Power Circuit Issues

Encoutering the C0800 code and wondering what it actually means? 

In simple terms, this code refers to a control module power circuit voltage issue. Don’t worry if you’re unfamiliar with technical jargon – that’s what we’re here for! 

In this article, we’ll explore the meaning, severity, symptoms, causes, and diagnosis of the C0800 code. 

So, let’s jump in!

C0800 Code: An Overview

The following points outline the key aspects of the C0800 code!

  • Definition: Control Module Power Circuit
  • Severity: Medium
  • DIY Skill Level: Intermediate
  • Continue To Drive?: Yes
  • Estimated Repair Cost: $50 – $500

What Does The C0800 Code Mean?

The C0800 code is a diagnostic trouble code that indicates an issue with the control module power circuit. Though this is a generic code that can appear in any vehicle, it is most commonly triggered in GM  models such as the Chevy (Equinox, Cruze, Silverado, Malibu) and GMC (Sierra and Terrain).

It’s worth noting that there are different variations of the C0800 code that provide additional information about the specific nature of the problem. For example:

  • C0800 0D: Control Module Power Circuit High Resistance/ Device Power 1 Circuit High Resistance
  • C0800 03: Control Module Power Circuit Low Voltage/ Device Power 1 Circuit Voltage Below Threshold
  • C0800 5A: Control Module Not Plausible
  • C0800 07: Control Module Power Circuit High Voltage/ Device Power 1 Circuit Voltage Above Threshold
  • C0800 11: Device Power 1 Circuit High Input
  • C0800 12: Control Module Power Circuit – Low Input
When the C0800 code and its variants appear, they indicate a problem with the control module power circuit. (Image credit: Terrain Forum)

To understand the C0800 code better, let’s take a look at the systems and components involved. Within an automobile engine, there are various control modules responsible for different functions, such as the engine control module (ECM), body control module (BCM), and transmission control module (TCM). These modules work together to ensure the smooth operation of your vehicle.

The C0800 code is typically triggered when there is a problem with the power circuit supplying voltage to these control modules. It can be caused by a faulty wiring harness, a malfunctioning power relay, or a weak battery. When the voltage in the power circuit falls below or exceeds the predetermined threshold, this code is stored in the vehicle’s onboard computer.

Read more: GM OBD2 Codes List For FREE Download 

How Serious Is The C0800 Code?

The severity level of the C0800 code can be classified as medium. While it indicates a problem in the control module power circuit, it is not an immediate cause for panic. 

You can continue to drive your vehicle with this code present, but it is still important to address the underlying issue. Ignoring the C0800 code for an extended period may lead to further complications or potential damage to other vehicle components. 

Read more: C0242 Code: Traction Control Malfunction in GM Vehicles

C0800 Code – Warning Signs To Watch Out For

The C0800 code typically presents with several noticeable symptoms, including:

  • Illuminated dashboard warning lights: check engine light, ABS warning light and traction control light 
  • Service StabiliTrak message
  • Loss of power or reduced engine performance
  • Erratic behavior of vehicle systems
  • Difficulty starting the vehicle

Exploring The Culprits Behind The Code C0800

To better understand the root causes of the C0800 code, consider the following possibilities:

  • Faulty wiring or connectors
  • Defective power relay
  • Weak battery or poor electrical connection
  • Issues with the control modules themselves

Note: It’s worth noting that there is a known issue with the E411 connector on the Equinox. It’s a common cause for this code on Equinox vehicles. Most of the time, it’s corroded and needs to be replaced. 

Diagnosis And Repair: Step-by-Step Guide

Are you ready to diagnose and repair the C0800 code? Our comprehensive guide provides step-by-step instructions and valuable insights to deal with this code.

Essential Tools And Parts

Step-by-step Procedure

Step 1: Begin by checking the battery voltage and performing a load test. Consider replacing the battery if necessary. 

Step 2: If the issue persists, check the voltage at the easiest accessible controller, such as the ABS module. Gradually move on to other controllers, checking for any voltage issues. 

Step 3: Verify the wiring connections for any signs of corrosion or loose connections and clean them if necessary. Pay special attention to the E411 connector near the tank if you own an Equinox model. If a faulty wiring harness or connector is identified, replace it with the appropriate replacement part.

Step 4: If the wiring check reveals no issues, test the control module and consider any necessary repair or replacement. 

Step 5: Clear the code and test drive your vehicle. 

Note: Throughout the process, refer to the wiring diagram for the specific vehicle model to ensure accurate diagnosis and repair.

Testing the battery is the first and foremost step you should take when encountering the C0800 code. Check this video to see how to do it!

DIY Repair Level And Estimated Costs

The DIY repair level for diagnosing and fixing the C0800 code is moderate. While the initial steps, such as checking the battery voltage, can be done by most car owners, troubleshooting the wiring and connectors may require some technical knowledge and expertise.

If you’re uncertain about tackling the repair yourself, it is always recommended to seek assistance from an expert or a qualified mechanic. They have the necessary tools, experience, and knowledge to diagnose and fix the issue accurately.

The estimated cost for repairing the C0800 code can vary depending on the specific cause and the need for replacement parts. It is advisable to consult with a mechanic for an accurate assessment of the repair costs. 

Explore estimated repair costs for C0800 code-related tasks in the table below.

Repair TaskEstimated Cost
Professional diagnosis fee$50 – $200
Battery load test$20 – $50
Wiring repair$100 – $300
Module replacement$200 – $1000

Final Thoughts

We understand car problems, like the C0800 code or any other OBD2 code, can be stressful. So, we want to ensure you have all the information you need to get your car fixed quickly and easily! If you’re uncomfortable working on your vehicle, I recommend taking it to a qualified mechanic. They’ll be able to diagnose the problem and fix it right away.

If you have any questions or insights, feel free to share them in the comments below.

Stay proactive in maintaining your vehicle and enjoy a smooth driving experience!

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