AutoCodes – Audi – P0642 Audi

P0642 Audi Code - Sensor Voltage Circuit 'A' Low Voltage

Quick Answer

This fault code is stored in the Engine Control Module (ECM) when a malfunction occurs with the sensor supply voltage circuit. Common causes include Faulty Engine Control Module (ECM), Engine Control Module harness is open or shorted, Engine 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: P0642 Audi indicates Sensor Voltage Circuit 'A' Low Voltage.
Common causes: Common causes include Faulty Engine Control Module (ECM), Engine Control Module harness is open or shorted, Engine 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 41,199

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 03, 2020

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

This fault code is stored in the Engine Control Module (ECM) when a malfunction occurs with the sensor supply voltage circuit. The Engine Control Module outputs a 5-volt supply voltage to certain sensors. Many components share the same 5-volt supply. If fault codes exist for multiple components that operate with a 5-volt supply the wiring from the Engine Control Module and the Engine Control Module itself should be tested. Also, each component should be disconnected in turn to identify a faulty component pulling down the supply circuit. The Diagnostic Trouble Code (DTC) will set when the Engine Control Module has detected the sensor 5-volt reference circuit voltage is lower than expected.

OBDII Code P0642 Audi - Sensor Voltage Circuit 'A' Low Voltage - AutoCodes.com — P0642 Audi Code - Sensor Voltage Circuit 'A' Low Voltage

What does this mean?

What are the Possible Causes of the DTC P0642 Audi?

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

How to Fix the DTC P0642 Audi?

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

There is a Factory Service Bulletin for the following Audi models:
2005-2007 Audi A3
2005-2007 Audi A4
2007 Audi A4 Cabriolet
2008 Audi TT
Audi Factory Service Bulletin OBDII Code P0642

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0642 Audi 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 Audi code?

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

Need Help with the Code?

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

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 Audi Code

1. What are the common symptoms of OBDII code P0642 in an Audi?

The common symptoms include check engine light illumination, poor engine performance, rough idling, and potential stalling of the vehicle.

2. What does the OBDII code P0642 in an Audi indicate?

The code P0642 indicates a low voltage condition in the Sensor Voltage Circuit 'A' of the vehicle's engine control module.

3. What are the possible causes of OBDII code P0642 in an Audi?

Possible causes include a faulty engine control module, damaged wiring or connectors, issues with the sensor itself, or a low battery voltage.

4. How can I diagnose the OBDII code P0642 in my Audi?

Diagnosis involves using an OBDII scanner to retrieve the code, checking the voltage levels at the sensor, inspecting the wiring and connectors for damage, and testing the sensor's functionality.

5. How can I repair OBDII code P0642 in my Audi?

Repair may involve replacing the faulty sensor, repairing damaged wiring or connectors, resetting the engine control module, or addressing any underlying issues causing the low voltage condition.

6. Can I drive my Audi with the OBDII code P0642?

It is not recommended to drive the vehicle with the code P0642 present, as it can lead to further engine issues and potential breakdowns.

7. How urgent is it to address the OBDII code P0642 in an Audi?

It is best to address the code as soon as possible to prevent any damage to the engine or other components of the vehicle.

8. Can I reset the OBDII code P0642 in my Audi myself?

You can attempt to reset the code using an OBDII scanner, but it is important to diagnose and repair the underlying issue causing the code to prevent it from reoccurring.

9. Is OBDII code P0642 a common issue in Audi vehicles?

While it may not be as common as some other codes, the P0642 code can still occur in Audi vehicles due to various factors affecting the sensor voltage circuit.

10. How much does it cost to repair OBDII code P0642 in an Audi?

The cost of repair can vary depending on the specific cause of the issue, but it is recommended to consult a professional mechanic for an accurate diagnosis and cost estimate.