AutoCodes – Buick – P1639 Buick

P1639 Buick Code - PCM 5 Volt Reference Voltage Circuit Condition

Quick Answer

The Powertrain Control Module (PCM) uses the 5-volt reference 2 circuit as a sensor feed for the A/C refrigerant pressure sensor. Common causes include Sensor using 5 volt reference line shorted to ground, Circuit short to ground. 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: P1639 Buick indicates PCM 5 Volt Reference Voltage Circuit Condition.
Common causes: Common causes include Sensor using 5 volt reference line shorted to ground, Circuit short to ground.
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 16,416

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 Sep 04, 2019

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P1639 Buick Description

The Powertrain Control Module (PCM) uses the 5-volt reference 2 circuit as a sensor feed for the A/C refrigerant pressure sensor. The PCM monitors the voltage on the 5-volt reference 2 circuit.

OBDII Code P1639 Buick - PCM 5 Volt Reference Voltage Circuit Condition - AutoCodes.com — P1639 Buick Code - PCM 5 Volt Reference Voltage Circuit Condition

What does this mean?

What are the Possible Causes of the DTC P1639 Buick?

Sensor using 5 volt reference line shorted to ground
Circuit short to ground

How to Fix the DTC P1639 Buick?

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 P1639 Buick 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.

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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 P1639 Buick Code

1. What are the common symptoms of OBDII code P1639 on a Buick related to the PCM 5 Volt Reference Voltage Circuit Condition?

- Common symptoms include engine stalling, rough idling, loss of power, and issues with various electrical components.

2. What are the possible causes of OBDII code P1639 in a Buick, indicating a PCM 5 Volt Reference Voltage Circuit Condition?

- Possible causes may include a faulty PCM, damaged wiring or connectors in the 5 volt reference circuit, or a malfunctioning sensor.

3. How can I diagnose the PCM 5 Volt Reference Voltage Circuit Condition issue causing OBDII code P1639 in my Buick?

- Diagnosing this issue typically involves checking the wiring and connectors for damage, testing the sensors connected to the 5 volt reference circuit, and inspecting the PCM for faults.

4. Can a DIY enthusiast repair the PCM 5 Volt Reference Voltage Circuit Condition issue triggering OBDII code P1639 in a Buick?

- While some basic troubleshooting steps can be performed by a DIY enthusiast, resolving this issue often requires advanced diagnostic equipment and knowledge. It's recommended to consult a professional mechanic.

5. Is it safe to continue driving my Buick with OBDII code P1639 due to the PCM 5 Volt Reference Voltage Circuit Condition?

- It is not recommended to drive the vehicle with this issue, as it can lead to further damage and potential safety hazards. It's best to address the problem promptly.

6. Are there any specific sensors commonly associated with triggering OBDII code P1639 related to the PCM 5 Volt Reference Voltage Circuit Condition in a Buick?

- Sensors commonly linked to this issue include the throttle position sensor (TPS), manifold absolute pressure (MAP) sensor, and engine coolant temperature (ECT) sensor.

7. How much does it typically cost to repair the PCM 5 Volt Reference Voltage Circuit Condition causing OBDII code P1639 in a Buick?

- The cost of repair can vary depending on the exact cause of the issue and the labor rates in your area. It's advisable to obtain quotes from reputable mechanics.

8. Can a weak battery or alternator problem trigger OBDII code P1639 due to the PCM 5 Volt Reference Voltage Circuit Condition in a Buick?

- Yes, a weak battery or alternator issue can affect the 5 volt reference circuit and potentially trigger this OBDII code. It's important to ensure the electrical system is in good condition.

9. Will resetting the OBDII code P1639 related to the PCM 5 Volt Reference Voltage Circuit Condition in my Buick make the problem go away?

- Resetting the code may temporarily clear the warning light, but it will not fix the underlying issue causing the fault code. Proper diagnosis and repair are necessary.

10. How long does it typically take to repair the PCM 5 Volt Reference Voltage Circuit Condition leading to OBDII code P1639 in a Buick?

- The repair time can vary based on the complexity of the issue and the availability of parts. In some cases, it may be resolved quickly, while in others, it could take several hours or more.