AutoCodes – Nissan – P0643 2008 Nissan Altima Sedan

P0643 2008 Nissan Altima Sedan Code - Sensor Power Supply Circuit Short

Quick Answer

The control module has 2 internal 5-volt reference buses called "5-volt reference 1" and"5-volt reference 2". Common causes include Faulty Engine Control Module (ECM), ECM harness is open or shorted, ECM 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: P0643 2008 Nissan Altima Sedan indicates Sensor Power Supply Circuit Short.
Common causes: Common causes include Faulty Engine Control Module (ECM), ECM harness is open or shorted, ECM 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 4,671

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 May 01, 2019

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P0643 2008 Nissan Altima Sedan Description

The control module has 2 internal 5-volt reference buses called "5-volt reference 1" and"5-volt reference 2". Each reference bus provided 5-volt reference circuit for more than one sensor. Therefore, a fault condition on one 5-volt reference circuit will affect the other 5-volt reference circuits connected to the reference bus. The control module monitors the voltage on the 5-volt reference buses.

OBDII Code P0643 2008 Nissan Altima Sedan - Sensor Power Supply Circuit Short - AutoCodes.com — P0643 2008 Nissan Altima Sedan Code - Sensor Power Supply Circuit Short

What does this mean?

What are the Possible Causes of the DTC P0643 2008 Nissan Altima Sedan?

Faulty Engine Control Module (ECM)
ECM harness is open or shorted
ECM circuit poor electrical connection
Shorted sensor on 5 volt circuit
Accelerator pedal position sensor (APP sensor 1)
Power steering pressure sensor
EVAP control system pressure sensor
Refrigerant pressure sensor
Camshaft position sensor
Battery current sensor

How to Fix the DTC P0643 2008 Nissan Altima Sedan?

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 P0643 2008 Nissan Altima Sedan 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 P0643 2008 Nissan Altima Sedan code?

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Need Help with the Code?

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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 P0643 2008 Nissan Altima Sedan Code

1. What does the OBDII code P0643 for a 2008 Nissan Altima Sedan mean?

The code P0643 indicates a problem in the Sensor Power Supply Circuit Short in the vehicle.

2. What are the common symptoms of a P0643 code in a 2008 Nissan Altima Sedan?

Common symptoms include issues with the vehicle's engine performance, such as rough idling, stalling, or lack of power.

3. What are the possible causes of a Sensor Power Supply Circuit Short in a 2008 Nissan Altima Sedan?

Potential causes include a faulty sensor, damaged wiring or connectors, a blown fuse, or a problem with the engine control module (ECM).

4. How do I diagnose a P0643 code in my 2008 Nissan Altima Sedan?

Diagnosis typically involves using a scan tool to retrieve the specific fault code and then inspecting the sensor, wiring, and connectors for any visible damage or issues.

5. Can I continue driving my 2008 Nissan Altima Sedan with a P0643 code?

It is not recommended to drive the vehicle with a P0643 code, as it can lead to further damage to the engine or emissions system.

6. How can I repair a Sensor Power Supply Circuit Short in my 2008 Nissan Altima Sedan?

Repairing a P0643 code may involve replacing the faulty sensor, repairing damaged wiring or connectors, checking and replacing fuses if necessary, or reprogramming the ECM.

7. Will resetting the check engine light resolve the P0643 code in my 2008 Nissan Altima Sedan?

Resetting the check engine light may temporarily clear the code, but it will likely reappear if the underlying issue causing the code is not addressed.

8. How much does it cost to repair a P0643 code in a 2008 Nissan Altima Sedan?

The cost of repairing a P0643 code can vary depending on the specific cause of the issue, parts needed, and labor costs at the repair shop. It is advisable to get a diagnostic and repair estimate from a qualified mechanic.

9. Can a DIY enthusiast fix a P0643 code in a 2008 Nissan Altima Sedan?

While some DIY enthusiasts may be able to diagnose and repair simple electrical issues, fixing a P0643 code may require specialized tools and expertise. It is recommended to consult a professional mechanic for proper diagnosis and repair.

10. How often does a Sensor Power Supply Circuit Short occur in a 2008 Nissan Altima Sedan?

Sensor Power Supply Circuit Short issues are relatively uncommon in a 2008 Nissan Altima Sedan, but they can occur due to sensor or electrical component failures. Regular maintenance and prompt repairs can help prevent such issues.