AutoCodes – Cadillac – P1664 Cadillac

P1664 Cadillac 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 Cadillac 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 2,928

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
Comments
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Code P1664 Cadillac Description

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

What does this mean?

What are the Possible Causes of the DTC P1664 Cadillac?

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 Cadillac?

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 Cadillac 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.