AutoCodes – Cadillac – P0977 Cadillac

P0977 Cadillac Code - Shift Solenoid 'B' Open Or Short To Power

Quick Answer

The shift solenoid 2 is part of the control solenoid valve assembly which has no serviceable parts. Common causes include Low transmission fluid level, Dirty transmission fluid, Faulty Transmission Control Solenoid Valve. 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: P0977 Cadillac indicates Shift Solenoid 'B' Open Or Short To Power.
Common causes: Common causes include Low transmission fluid level, Dirty transmission fluid, Faulty Transmission Control Solenoid Valve.
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 2,404

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 Mar 25, 2024

Description
Possible Causes
How To Fix
Cost to Diagnose
Comments
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Code P0977 Cadillac Description

The shift solenoid 2 is part of the control solenoid valve assembly which has no serviceable parts. The shift solenoid 2 is a normally closed ON/OFF solenoid and is controlled by the Transmission Control Module through a low side driver. When the shift solenoid 2 is energized, shift solenoid 2 fluid pressure is directed to the clutch select valve 3. Power to the shift solenoid 2 is supplied by the Transmission Control Module through a high-side driver. The high-side driver protects the circuit and components from excessive current flow. If excessive current flow is detected, the high side driver will turn OFF. When the fault is corrected, the high-side driver will reset. The Diagnostic Trouble Code (DTC) will be set when the Transmission Control Module detects an internal high voltage electrical malfunction of the shift solenoid 2 control circuit when the shift solenoid 2 is commanded ON for 2 seconds.

OBDII Code P0977 Cadillac - Shift Solenoid 'B' Open Or Short To Power - AutoCodes.com — P0977 Cadillac Code - Shift Solenoid 'B' Open Or Short To Power

What does this mean?

What are the Possible Causes of the DTC P0977 Cadillac?

Low transmission fluid level
Dirty transmission fluid
Faulty Transmission Control Solenoid Valve
Transmission Control Solenoid Valve harness is open or shorted
Transmission Control Solenoid Valve circuit poor electrical connection

How to Fix the DTC P0977 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 P0977 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.