AutoCodes – GMC – P1664 GMC

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

Quick Answer

With the engine speed over 600 rpm, the Powertrain Control Module (PCM) detects the commanded state of the Up-Shift driver and the Actual state of the control circuit did not match, all conditions met for over 5 seconds. Common causes include Faulty Up-Shift driver, Up-Shift driver harness is open or shorted, Up-Shift driver 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: P1664 GMC indicates Skip Shift 1-4 Upshift Lamp Control Circuit.
Common causes: Common causes include Faulty Up-Shift driver, Up-Shift driver harness is open or shorted, Up-Shift driver 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 3,755

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 07, 2019

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P1664 GMC Description

OBDII Code P1664 GMC - Skip Shift 1-4 Upshift Lamp Control Circuit - AutoCodes.com — P1664 GMC Code - Skip Shift 1-4 Upshift Lamp Control Circuit

What does this mean?

What are the Possible Causes of the DTC P1664 GMC?

Faulty Up-Shift driver
Up-Shift driver harness is open or shorted
Up-Shift driver circuit poor electrical connection

How to Fix the DTC P1664 GMC?

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 P1664 GMC 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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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.