AutoCodes – Chevrolet – P0642 Chevrolet

P0642 Chevrolet Code - 5 Volt Reference 1 Circuit Low Voltage

Quick Answer

The Engine Control Module (ECM) has four (4) internal 5 Volt reference circuits (Some models have two (2) internal 5 Volt reference circuits). Common causes include Faulty Sensor on 5 Volt circuit, Sensor on 5 Volt circuit harness is open or shorted, Sensor on 5 Volt 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 Chevrolet indicates 5 Volt Reference 1 Circuit Low Voltage.
Common causes: Common causes include Faulty Sensor on 5 Volt circuit, Sensor on 5 Volt circuit harness is open or shorted, Sensor on 5 Volt 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 7,282

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 Jul 17, 2022

Description
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
FAQs
Comments
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Code P0642 Chevrolet Description

The Engine Control Module (ECM) has four (4) internal 5 Volt reference circuits (Some models have two (2) internal 5 Volt reference circuits). Each internal reference circuit provides external 5 Volt reference circuits for more than one sensor. A short to ground or short to voltage on one external 5 Volt reference circuit can affect all the components connected to the same internal 5 Volt reference circuit. The Diagnostic Trouble Code (DTC) will be set when the ECM detects a lower than the expected voltage on any of the 5 Volt reference circuits for greater than 0.5 s.

OBDII Code P0642 Chevrolet - 5 Volt Reference 1 Circuit Low Voltage - AutoCodes.com — P0642 Chevrolet Code - 5 Volt Reference 1 Circuit Low Voltage

What does this mean?

What are the Possible Causes of the DTC P0642 Chevrolet?

Faulty Sensor on 5 Volt circuit
Sensor on 5 Volt circuit harness is open or shorted
Sensor on 5 Volt circuit poor electrical connection
Faulty Engine Control Module (ECM)

How to Fix the DTC P0642 Chevrolet?

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

Disconnecting one component at a time from the affected 5 Volt reference circuit while observing the scan tool 5 Volt Reference Circuit Status parameter may help locate the fault. The scan tool parameter will change from Malfunction to OK when the source of the fault is disconnected. If all 5 Volt reference components have been disconnected and a fault is still indicated, the fault may exist in the wiring harness.

The 5 Volt reference 1 circuit provides 5 Volt to the following sensors: (Some models may have different sensors, please consult the factory service manual for the list of sensors for your model and year)

- Air conditioning (A/C) refrigerant pressure sensor
- Camshaft position sensor
- Engine oil pressure sensor
- Fuel pressure sensor
- Fuel rail pressure sensor
- Fuel tank pressure sensor
- Multifunction intake air sensor

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0642 Chevrolet 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 Chevrolet code?

Need more information on how to fix the P0642 Chevrolet code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P0642 Chevrolet code diagnosed by a professional: Find a repair shop in your area

Information for Specific Chevrolet Models

P0642 2014 Chevrolet Silverado — 5 Volt Reference 1 Circuit Low Voltage
P0642 2015 Chevrolet Silverado — 5 Volt Reference 1 Circuit Low Voltage
P0642 2016 Chevrolet Silverado — 5 Volt Reference 1 Circuit Low Voltage
P0642 2017 Chevrolet Silverado — 5 Volt Reference 1 Circuit Low Voltage
P0642 2018 Chevrolet Silverado — 5 Volt Reference 1 Circuit Low Voltage

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 Chevrolet Code

1. What are the common symptoms of OBDII code P0642 in a Chevrolet related to the 5 Volt Reference 1 Circuit Low Voltage?

The common symptoms include engine stalling, rough idling, poor acceleration, and issues with the vehicle's electronic systems.

2. What are the possible causes of the P0642 code indicating 5 Volt Reference 1 Circuit Low Voltage in a Chevrolet?

Possible causes include a faulty Engine Control Module (ECM), damaged wiring or connectors in the 5 Volt Reference circuit, or a malfunctioning sensor connected to the circuit.

3. How can I diagnose the OBDII code P0642 in a Chevrolet related to low voltage in the 5 Volt Reference 1 Circuit?

To diagnose this issue, you can use a multimeter to test the voltage in the circuit, inspect the wiring and connectors for any damage, and check the sensors connected to the circuit for proper operation.

4. Can a DIY enthusiast repair the P0642 code indicating low voltage in the 5 Volt Reference 1 Circuit on a Chevrolet?

While some DIY enthusiasts may be able to diagnose and repair this issue, it is recommended to seek professional help due to the complexity of the electrical system involved.

5. Are there any safety precautions to consider when working on the 5 Volt Reference 1 Circuit in a Chevrolet to resolve the P0642 code?

When working on the electrical system, always disconnect the battery to prevent electrical shocks, handle wiring and connectors carefully, and follow proper safety procedures outlined in the vehicle's manual.

6. How important is it to address the OBDII code P0642 indicating low voltage in the 5 Volt Reference 1 Circuit on a Chevrolet?

It is crucial to address this issue promptly as it can lead to performance issues, potential damage to the vehicle's electronic systems, and even safety hazards while driving.

7. Can resetting the OBDII system clear the P0642 code related to the 5 Volt Reference 1 Circuit Low Voltage in a Chevrolet?

Resetting the OBDII system may temporarily clear the code, but if the underlying issue causing the low voltage in the circuit is not resolved, the code is likely to reappear.

8. How much should I expect to pay for professional repairs related to the P0642 code on a Chevrolet indicating low voltage in the 5 Volt Reference 1 Circuit?

The cost of repairs can vary depending on the exact cause of the issue, but it is advisable to budget for diagnostic fees, parts replacement costs, and labor charges when seeking professional help.

9. Are there any recalls or technical service bulletins (TSBs) related to the OBDII code P0642 in Chevrolet vehicles concerning the 5 Volt Reference 1 Circuit Low Voltage?

It is recommended to check with Chevrolet dealerships or online databases for any recalls or TSBs related to this specific OBDII code to see if there are known issues or solutions provided by the manufacturer.

10. Will driving my Chevrolet with the OBDII code P0642 indicating low voltage in the 5 Volt Reference 1 Circuit cause further damage?

Continued driving with this code may lead to additional issues with the vehicle's performance and electronic systems, so it is best to address the problem as soon as possible to prevent further damage.