AutoCodes – GMC – B1004 GMC

B1004 GMC Code - Keep Alive Memory

Quick Answer

This fault is internal. Common causes include Faulty Control Module, Control Module harness is open or shorted, Control Module circuit poor electrical connection. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means: B1004 GMC indicates Keep Alive Memory.
Common causes: Common causes include Faulty Control Module, Control Module harness is open or shorted, Control Module circuit poor electrical connection.
Severity: High - diagnose this code as soon as possible.
Can I drive?: Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

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Code Popularity 2,529

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

What is this?

Table of contents Created and updated by William Orellana on Mar 11, 2021

Description
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
FAQs
Comments
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Code B1004 GMC Description

This fault is internal. No external circuits are involved. Module microprocessor must be active/awake for the Diagnostic Trouble Code (DTC) to set. The microprocessor calculates the checksum on those areas of memory that hold critical operation data. This is done at a regular interval and is called a periodic checksum. The microprocessor also calculates a checksum on these memory locations whenever new data is written to them. This is called the running checksum. The microprocessor compares periodic checksum to running checksum. If they do not match, the microprocessor sets DTC B1004.
When DTC is set, microprocessor reverts back to base programmed critical operating data until new data is learned and stored in Keep Alive Memory (KAM). DTC will clear when the microprocessor calculates a successful comparison of periodic checksum to running checksum.

OBDII Code B1004 GMC - Keep Alive Memory - AutoCodes.com — B1004 GMC Code - Keep Alive Memory

What does this mean?

What are the Possible Causes of the DTC B1004 GMC?

Faulty Control Module
Control Module harness is open or shorted
Control Module circuit poor electrical connection

How to Fix the DTC B1004 GMC?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What does this mean?

Code Tech Notes

This Diagnostic Trouble Code (DTC) may be stored as history without affecting the operation of the module. If DTC is stored only as history and not current, do not replace the module. DTC will never set as current during testing unless a non-recoverable memory failure. Intermittent interruptions to either hot at all times supply or processor ground will cause the module to set DTC. If this DTC is retrieved as both current and history, replace the module that set DTC.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the B1004 GMC code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

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About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

Frequently Asked Questions about B1004 GMC Code

1. What does OBDII code B1004 GMC mean?

The code B1004 GMC refers to a Keep Alive Memory error, indicating an issue with the vehicle's memory retention system.

2. What are the common symptoms of OBDII code B1004 GMC?

Common symptoms of code B1004 GMC include difficulty starting the vehicle, loss of radio presets, clock resetting, and the need to reprogram keyless entry systems.

3. What are the possible causes of OBDII code B1004 GMC?

Possible causes of code B1004 GMC can include a faulty body control module (BCM), a drained or faulty battery, poor electrical connections, or a malfunctioning Keep Alive Memory circuit.

4. How do I diagnose OBDII code B1004 GMC?

Diagnosing code B1004 GMC typically involves using an OBDII scanner to retrieve the code, checking the vehicle's battery voltage and connections, inspecting the BCM and related wiring, and performing a system reset if necessary.

5. How can I repair OBDII code B1004 GMC?

To repair code B1004 GMC, you may need to replace a faulty BCM, repair any damaged wiring or connections, ensure the battery is in good condition, and perform a system reset to clear the error code.

6. Can I drive my vehicle with OBDII code B1004 GMC?

It is generally safe to drive your vehicle with code B1004 GMC, but it is recommended to address the issue promptly to prevent further electrical problems and ensure proper vehicle operation.

7. Will resetting the OBDII code B1004 GMC fix the issue?

Resetting the code may temporarily clear the error, but if the underlying issue such as a faulty BCM or battery problem persists, the code is likely to reappear. It's important to diagnose and repair the root cause.

8. How much does it cost to repair OBDII code B1004 GMC?

The cost of repairing code B1004 GMC can vary depending on the specific cause of the issue, the extent of the repairs needed, and labor rates in your area. It's recommended to consult a professional mechanic for an accurate estimate.

9. Can a DIY enthusiast fix OBDII code B1004 GMC?

While some basic troubleshooting steps can be performed by a DIY enthusiast, diagnosing and repairing code B1004 GMC may require specialized tools and expertise. It's advisable to seek professional help for complex electrical issues.

10. How often does OBDII code B1004 GMC occur in GMC vehicles?

Code B1004 GMC related to Keep Alive Memory issues is relatively uncommon but can occur in GMC vehicles due to various electrical and component failures. Regular vehicle maintenance can help prevent such issues.