AutoCodes – Hyundai – P0642 Hyundai

P0642 Hyundai Code - Sensor Reference Voltage 'A' Circuit Low

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: P0642 Hyundai indicates Sensor Reference Voltage 'A' Circuit Low.
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 34,461

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 P0642 Hyundai 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 P0642 Hyundai - Sensor Reference Voltage 'A' Circuit Low - AutoCodes.com — P0642 Hyundai Code - Sensor Reference Voltage 'A' Circuit Low

What does this mean?

What are the Possible Causes of the DTC P0642 Hyundai?

Faulty Engine Control Module (ECM)
ECM harness is open or shorted
ECM circuit poor electrical connection
Shorted sensor on 5 volt circuit

How to Fix the DTC P0642 Hyundai?

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 P0642 Hyundai 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 P0642 Hyundai 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 P0642 Hyundai Code

1. What are the common symptoms of OBDII code P0642 in a Hyundai?

The common symptoms of OBDII code P0642 in a Hyundai include rough idling, engine stalling, decreased fuel efficiency, and an illuminated Check Engine Light.

2. What does the OBDII code P0642 Hyundai indicate?

OBDII code P0642 in a Hyundai indicates a problem with the Sensor Reference Voltage 'A' Circuit, specifically a low voltage condition.

3. What are the possible causes of OBDII code P0642 in a Hyundai?

Possible causes of OBDII code P0642 in a Hyundai include a faulty sensor, damaged wiring or connectors in the reference voltage circuit, a malfunctioning PCM (Powertrain Control Module), or a low battery voltage.

4. How serious is OBDII code P0642 in a Hyundai?

OBDII code P0642 should be addressed promptly as it can lead to performance issues and potential damage to other components if left unresolved.

5. How can I diagnose OBDII code P0642 in my Hyundai?

Diagnosing OBDII code P0642 in a Hyundai typically involves using a scan tool to retrieve the code, inspecting the reference voltage circuit for any visible damage, and testing the sensor and related components for proper functionality.

6. Can I drive my Hyundai with OBDII code P0642?

It is not recommended to drive your Hyundai with OBDII code P0642, as it can cause drivability issues and potentially lead to further damage if the underlying problem is not addressed.

7. How can I repair OBDII code P0642 in my Hyundai?

Repairing OBDII code P0642 in a Hyundai may involve replacing the faulty sensor, repairing damaged wiring or connectors, resetting the PCM, or addressing any other underlying issues causing the low voltage condition.

8. Is it possible to reset OBDII code P0642 in a Hyundai by disconnecting the battery?

Disconnecting the battery may temporarily clear the code, but it is not a recommended long-term solution as the underlying issue causing the low voltage condition will still need to be addressed to prevent the code from reoccurring.

9. How much does it cost to fix OBDII code P0642 in a Hyundai?

The cost of fixing OBDII code P0642 in a Hyundai can vary depending on the specific cause of the issue, the labor rates of the repair shop, and the cost of any replacement parts needed.

10. Can OBDII code P0642 in a Hyundai cause other problems if not repaired?

If left unrepaired, OBDII code P0642 in a Hyundai can potentially cause drivability issues, decreased fuel efficiency, and may lead to further damage to other components in the vehicle over time.