AutoCodes – Isuzu – P0642 Isuzu

P0642 Isuzu Code - 5 Volt Reference 1 Circuit Low Voltage

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 Isuzu indicates 5 Volt Reference 1 Circuit Low Voltage.
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 9,577

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

What does this mean?

What are the Possible Causes of the DTC P0642 Isuzu?

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 Isuzu?

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 Isuzu 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 Isuzu 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 Isuzu Code

1. What does OBDII code P0642 mean for Isuzu vehicles?

The P0642 code indicates a low voltage condition in the 5-volt reference 1 circuit of the engine control module (ECM) in an Isuzu vehicle.

2. What are the common symptoms of a P0642 Isuzu trouble code?

Common symptoms of a P0642 code may include engine stalling, rough idling, poor acceleration, and in some cases, the vehicle may not start at all.

3. What can cause the P0642 Isuzu code to trigger?

The P0642 code in Isuzu vehicles is commonly triggered by issues such as a faulty 5-volt reference circuit, damaged wiring, a defective ECM, or a failing sensor connected to the circuit.

4. How can I diagnose the P0642 code on my Isuzu?

Diagnosing the P0642 code typically involves using a scan tool to check for the code, inspecting the 5-volt reference 1 circuit for any visible damage, and testing the sensors and wiring connected to the circuit for proper functioning.

5. Can I drive my Isuzu with a P0642 trouble code?

It is not recommended to drive your Isuzu with a P0642 code, as it can lead to further damage to the engine or related components. It is best to address the issue promptly.

6. How can I repair a P0642 Isuzu trouble code?

Repairing a P0642 code may involve replacing damaged wiring, repairing connections, replacing the ECM if faulty, or addressing any issues with sensors connected to the 5-volt reference 1 circuit.

7. Are there any DIY tips for fixing a P0642 code on an Isuzu?

While basic troubleshooting like checking for loose connections or damaged wiring can be done by DIY enthusiasts, resolving the root cause of the P0642 code may require professional diagnostic equipment and expertise.

8. Can a P0642 code be a recurring issue in Isuzu vehicles?

If the root cause of the P0642 code is not properly addressed, it can become a recurring issue in Isuzu vehicles. It is essential to ensure a thorough diagnosis and repair to prevent future occurrences.

9. Will resetting the OBDII system clear the P0642 code in my Isuzu?

Resetting the OBDII system may clear the P0642 code temporarily, but if the underlying issue is not fixed, the code is likely to reappear. It is crucial to address the root cause of the problem.

10. Is the P0642 code specific to Isuzu vehicles only?

While the P0642 code is commonly associated with Isuzu vehicles, it can also occur in other makes and models. The specific repair steps may vary depending on the vehicle manufacturer and model.