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P1664 GMC Code - Skip Shift 1-4 Upshift Lamp Control Circuit

Quick Answer

The P1664 GMC diagnostic trouble code (DTC) refers to the Skip Shift 1-4 Upshift Lamp Control Circuit. Common causes include Faulty skip shift control module, Damaged or corroded wiring in the skip shift control circuit, Malfunctioning skip shift solenoid. 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
P1664 GMC indicates Skip Shift 1-4 Upshift Lamp Control Circuit.
Common causes
Common causes include Faulty skip shift control module, Damaged or corroded wiring in the skip shift control circuit, Malfunctioning skip shift solenoid.
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 12, 2024
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Code P1664 GMC Description

The P1664 GMC diagnostic trouble code (DTC) refers to the Skip Shift 1-4 Upshift Lamp Control Circuit. This code is specific to GMC vehicles and is related to the control circuit that operates the skip shift function in the transmission. The skip shift function is designed to improve fuel efficiency by forcing the driver to shift from 1st gear directly to 4th gear under certain driving conditions. This code indicates a malfunction in the control circuit that operates the skip shift function, which can lead to various issues with the vehicle's performance.

OBDII Code P1664 GMC - Skip Shift 1-4 Upshift Lamp Control Circuit
P1664 GMC Code - Skip Shift 1-4 Upshift Lamp Control Circuit

Common Causes of P1664 GMC

  1. Faulty skip shift control module
  2. Damaged or corroded wiring in the skip shift control circuit
  3. Malfunctioning skip shift solenoid
  4. Issues with the skip shift indicator lamp
  5. Electronic control module (ECM) malfunction

Symptoms of P1664 GMC

  1. Check engine light illuminated on the dashboard
  2. Skip shift indicator lamp not functioning properly
  3. Rough or erratic shifting
  4. Decreased fuel efficiency
  5. Potential transmission issues

How to Fix P1664 GMC

  1. Begin by diagnosing the root cause of the issue using a diagnostic scanner to retrieve the specific fault codes and pinpoint the problem.
  2. Inspect the skip shift control module, wiring, and solenoid for any signs of damage, corrosion, or malfunction.
  3. Repair or replace any faulty components identified during the diagnostic process, such as the control module, wiring, solenoid, or indicator lamp.
  4. Clear the fault codes from the vehicle's computer using the diagnostic scanner and test drive the vehicle to ensure that the issue has been resolved.
  5. If the problem persists, further troubleshooting may be necessary to identify any underlying issues with the transmission or ECM that could be contributing to the P1664 code.

Cost to Fix P1664 GMC

The cost of repairing the P1664 GMC code can vary depending on the specific cause of the issue and the labor rates at the auto repair shop. In general, the cost of parts for this repair could range from $100 to $300, while labor costs could add another $100 to $200 to the total bill. Additional diagnostic time may be required to pinpoint the exact cause of the issue, so it's important to factor in these costs as well. Overall, the total repair cost for addressing the P1664 code could range from $200 to $500 or more, depending on the extent of the repairs needed. It's recommended to consult with a qualified mechanic or dealership for a more accurate cost estimate based on your specific vehicle make and model.

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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 P1664 GMC Code

1. What are the common symptoms of OBDII code P1664 in a GMC vehicle?

- Common symptoms of code P1664 include the 1-4 skip shift indicator not working properly, the upshift lamp not illuminating, and potential issues with shifting between gears.

2. What causes the Skip Shift 1-4 Upshift Lamp Control Circuit malfunction in a GMC vehicle?

- The most common causes of code P1664 in a GMC vehicle are a faulty upshift lamp control circuit, damaged wiring or connectors, or a malfunctioning skip shift solenoid.

3. How can I diagnose the Skip Shift 1-4 Upshift Lamp Control Circuit issue in my GMC vehicle?

- Diagnosing code P1664 involves checking the wiring and connectors related to the upshift lamp control circuit, testing the skip shift solenoid, and using a scan tool to monitor the system for any abnormalities.

4. Can I continue driving my GMC vehicle with OBDII code P1664 present?

- It is generally safe to continue driving your GMC vehicle with code P1664, but it is recommended to address the issue promptly to prevent any potential shifting problems or further damage to the transmission.

5. Is it possible to repair the Skip Shift 1-4 Upshift Lamp Control Circuit issue myself?

- Repairing the upshift lamp control circuit issue yourself is possible if you have the necessary tools, knowledge, and experience in automotive electrical systems. Otherwise, it is best to seek professional help.

6. How much does it typically cost to fix OBDII code P1664 in a GMC vehicle?

- The cost of repairing code P1664 can vary depending on the cause of the issue, the extent of the damage, and the labor rates in your area. It is advisable to get a diagnostic and repair estimate from a qualified mechanic.

7. Are there any preventive measures to avoid encountering the Skip Shift 1-4 Upshift Lamp Control Circuit problem in my GMC vehicle?

- Regular maintenance, such as checking the electrical connections and wiring related to the upshift lamp control circuit, can help prevent issues like code P1664 from occurring in your GMC vehicle.

8. Can extreme weather conditions affect the Skip Shift 1-4 Upshift Lamp Control Circuit in a GMC vehicle?

- Extreme weather conditions, such as extreme heat or cold, can potentially affect the performance of the upshift lamp control circuit, leading to issues like code P1664. It is important to keep your vehicle well-maintained in all weather conditions.

9. Will resetting the OBDII system clear the P1664 code in my GMC vehicle?

- Resetting the OBDII system may temporarily clear the P1664 code, but if the underlying issue with the upshift lamp control circuit is not addressed, the code is likely to reappear. It is recommended to diagnose and fix the root cause of the problem.

10. How long does it typically take to repair the Skip Shift 1-4 Upshift Lamp Control Circuit issue in a GMC vehicle?

- The repair time for code P1664 can vary depending on the complexity of the issue and the availability of parts. In general, it may take a few hours to a day to diagnose and repair the upshift lamp control circuit problem in a GMC vehicle.

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