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P1639 Chevrolet Code - PCM 5 Volt Reference Voltage Circuit Condition

Quick Answer

The P1639 Chevrolet code indicates a problem with the PCM (Powertrain Control Module) 5-volt reference voltage circuit. Common causes include Faulty PCM, Damaged wiring or connectors in the 5-volt reference circuit, Short circuit in the reference voltage circuit. 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 Chevrolet indicates PCM 5 Volt Reference Voltage Circuit Condition.
Common causes
Common causes include Faulty PCM, Damaged wiring or connectors in the 5-volt reference circuit, Short circuit in the reference voltage circuit.
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.
What is this?
Table of contents Created and updated by William Orellana on Sep 07, 2024
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Code P1639 Chevrolet Description

The P1639 Chevrolet code indicates a problem with the PCM (Powertrain Control Module) 5-volt reference voltage circuit. The PCM is responsible for controlling various aspects of the vehicle's engine and transmission functions. The 5-volt reference voltage circuit provides a stable 5-volt supply to various sensors and components throughout the vehicle, allowing them to function properly.

OBDII Code P1639 Chevrolet - PCM 5 Volt Reference Voltage Circuit Condition
P1639 Chevrolet Code - PCM 5 Volt Reference Voltage Circuit Condition

Common Causes of P1639 Chevrolet

  1. Faulty PCM
  2. Damaged wiring or connectors in the 5-volt reference circuit
  3. Short circuit in the reference voltage circuit
  4. Malfunctioning sensor drawing excessive current
  5. Corrosion in the electrical connections

Symptoms of P1639 Chevrolet

  1. Rough idle or stalling
  2. Decreased fuel efficiency
  3. Engine misfires
  4. Check Engine Light illuminated
  5. Reduced engine performance

How to Fix P1639 Chevrolet

  1. Perform a thorough inspection of the wiring and connectors in the 5-volt reference circuit to check for any damage or corrosion.
  2. Test the sensors connected to the reference voltage circuit to determine if any are drawing too much current.
  3. Check the PCM for any signs of damage or malfunction and replace if necessary.
  4. Clear the diagnostic trouble codes from the PCM memory and reset the system to see if the issue persists.
  5. Test drive the vehicle to ensure that the symptoms associated with the P1639 code have been resolved.

Cost to Fix P1639 Chevrolet

The typical repair costs for addressing a P1639 Chevrolet code can range from $200 to $500, depending on the specific cause of the issue and the cost of parts and labor in your area. It's important to note that diagnosis time and labor rates at auto repair shops can vary significantly, so it's advisable to get a few quotes from different shops before proceeding with the repair. Remember that rates may be higher at dealerships or in metropolitan areas, while independent shops may offer more competitive prices.

When is the Code Detected?

If the voltage is out of tolerance, the Powertrain Control Module (PCM) will set DTC P1639.

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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 Chevrolet Code

1. What are common symptoms of OBDII code P1639 in a Chevrolet vehicle?

- Common symptoms include engine stalling, rough idle, decreased fuel efficiency, and issues with vehicle acceleration.

2. What causes the P1639 code to trigger in a Chevrolet car or truck?

- The code is typically triggered by a malfunction in the PCM 5-volt reference voltage circuit, which may be caused by wiring issues, a faulty PCM, or a short circuit.

3. How serious is the P1639 code in a Chevrolet vehicle?

- The P1639 code can potentially lead to engine performance issues and should be addressed promptly to avoid further damage to the vehicle.

4. How can I diagnose the PCM 5-volt reference voltage circuit condition in my Chevrolet to resolve the P1639 code?

- Diagnosing the issue may involve checking the wiring harness for damage, testing the PCM for faults, and using a multimeter to measure voltage at various points in the circuit.

5. Can I fix the PCM 5-volt reference voltage circuit issue triggering the P1639 code myself?

- While some DIY enthusiasts may be able to address the issue, it is recommended to consult a professional mechanic with experience in diagnosing and repairing OBDII codes like P1639.

6. Is it safe to drive my Chevrolet with the P1639 code present?

- It is not recommended to drive the vehicle with the P1639 code active, as it can lead to potential engine performance issues and further damage if left unresolved.

7. How much does it typically cost to repair the PCM 5-volt reference voltage circuit issue causing the P1639 code in a Chevrolet?

- Repair costs can vary depending on the exact cause of the issue and labor rates in your area, but it is advisable to budget for potential PCM replacement or wiring repairs.

8. Can the P1639 code be intermittent in a Chevrolet vehicle?

- Yes, the P1639 code can sometimes be intermittent, making it important to address the underlying issue even if the symptoms temporarily disappear.

9. Will resetting the OBDII system clear the P1639 code in my Chevrolet?

- Resetting the system may temporarily clear the code, but it is likely to return if the underlying issue with the PCM 5-volt reference voltage circuit is not resolved.

10. Are there any recalls or technical service bulletins related to the P1639 code in Chevrolet vehicles?

- It is advisable to check with a Chevrolet dealership or online databases for any recalls or technical service bulletins related to the P1639 code in your specific vehicle model.

Discuss the causes and fixes for P1639 Chevrolet OBDII Code

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  • 2001 Chevy s10 balzer 4x4 4 door code 1639

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  • i HAVE A 2002 CHEVY SILVERADO THAT WAS GIVING A P1639 CODE. THE TRUCK WAS RUNNING ROUGH IDLING ABOUT 400RPMS HIGHER THAN NORMAL AND SURGING. IT WOULD CUT OUT AND APPEAR TO HAVE ERATIC SHIFTING. AFTER SEVERAL DAYS OF CHECKING A/C REFRIDGERANT PRESSURE SENSORS, FUEL TANK PRESSURE SENSORS TPS SENSOR I FINALLY FOUND THAT THE PCM HAD WATER UNDER THE PLUG AND WAS SHORTING THE 5 VOLT REFERENCE. I HAVE YET TO SEE A POST REGARDING WATER IN THE HARNESS FOR THIS CODE AND WANTED TO POST FOR THOSE THAT ARE STRUGGLING WITH THIS CODE. EVERYONE SAYS THIS CODE SHOULDNT EFFECT THE VEHICLES PERFORMANCE, HOG WASH. TO CORRECT, I BLEW THE PINS OUT WITH COMPRESSED AIR AND SPRAYED WITH ELECTRICAL CONTACT CLEANER. I THEN COATED THE PINS WITH DIELECTRIC LUBE AND REINSERTED THE PLUG HARNESS INTO THE PCM. PROBLEM SOLVED.

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