AutoCodes – Generic – P1794

P1794 Code - Battery Supply Circuit Malfunction

Quick Answer

The Diagnostic Trouble Code (DTC) is set when the voltage at the terminal on Engine Control Module (ECM) harness connector is less than 1.4 volts (other than during starting). Common causes include Faulty Battery, Low battery charge, Blown fuse. 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: P1794 indicates Battery Supply Circuit Malfunction.
Common causes: Common causes include Faulty Battery, Low battery charge, Blown fuse.
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 54,456

How popular is this code, among other codes? Medium

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 Jul 19, 2021

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P1794 Description

The Diagnostic Trouble Code (DTC) is set when the voltage at the terminal on Engine Control Module (ECM) harness connector is less than 1.4 volts (other than during starting). Before doing any repairs, ensure the battery is fully charged and in acceptable condition.

OBDII Code P1794 - Battery Supply Circuit Malfunction - AutoCodes.com — P1794 Code - Battery Supply Circuit Malfunction

What does this mean?

What are the Possible Causes of the DTC P1794?

Faulty Battery
Low battery charge
Blown fuse

How to Fix the DTC P1794?

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 is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P1794 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.

Need more information about the P1794 code?

Need more information on how to fix the P1794 code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P1794 code diagnosed by a professional: Find a repair shop in your area

Information for Specific Makes

P1794 Acura — Automatic Transmission BARO Signal
P1794 Honda — Automatic Transmission BARO Signal
P1794 Isuzu — Automatic Transmission BARO Signal
P1794 KIA — Battery Voltage Circuit Malfunction
P1794 Mazda — Battery Supply Circuit Malfunction

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 P1794 Code

1. What are the common symptoms of OBDII code P1794 (Battery Supply Circuit Malfunction)?

- Common symptoms include issues with starting the vehicle, dimming or flickering lights, and irregular operation of electrical components.

2. What are the possible causes of OBDII code P1794?

- The code P1794 can be triggered by a faulty battery, alternator, battery cables, or a malfunctioning power control module.

3. How can I diagnose the Battery Supply Circuit Malfunction related to code P1794?

- Diagnosing code P1794 involves checking the battery voltage, inspecting the battery cables for corrosion or damage, and testing the alternator output.

4. Can a weak battery cause OBDII code P1794 to appear?

- Yes, a weak or failing battery can cause voltage irregularities that trigger the Battery Supply Circuit Malfunction code P1794.

5. What repair tips can help resolve OBDII code P1794?

- Repair tips include checking and replacing the battery if necessary, inspecting and cleaning battery cables, and ensuring proper connection to the alternator.

6. Is it safe to continue driving with OBDII code P1794 present?

- It is not recommended to continue driving with code P1794 as it can lead to further electrical issues and potential breakdowns.

7. Can a DIY enthusiast fix OBDII code P1794 at home?

- Depending on the cause, a DIY enthusiast may be able to resolve code P1794 by checking the battery, cables, and alternator. However, professional help may be needed for complex issues.

8. How much does it typically cost to repair OBDII code P1794?

- The repair cost for code P1794 can vary depending on the underlying issue, but it may range from $100 to $500 for parts and labor.

9. Will disconnecting and reconnecting the battery reset OBDII code P1794?

- Disconnecting and reconnecting the battery may temporarily clear the code, but it is recommended to diagnose and fix the root cause to prevent the code from reappearing.

10. Can extreme weather conditions contribute to triggering OBDII code P1794?

- Yes, extreme temperatures can affect battery performance and contribute to triggering code P1794, especially in cold weather when batteries may struggle to maintain proper voltage levels.