AutoCodes – Lexus – P0977 Lexus

P0977 Lexus Code - Shift Solenoid 'B' Control Circuit High

Quick Answer

The Engine Control Module (ECM) commands gear shifts by turning the shift solenoid valves "ON/OFF". Common causes include Low transmission fluid level, Dirty transmission fluid, Faulty shift solenoid 'B' 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 Lexus indicates Shift Solenoid 'B' Control Circuit High.
Common causes: Common causes include Low transmission fluid level, Dirty transmission fluid, Faulty shift solenoid 'B' 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 4,074

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 May 11, 2019

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

The Engine Control Module (ECM) commands gear shifts by turning the shift solenoid valves "ON/OFF". When there is an open or short circuit in any shift solenoid valve circuit, the ECM detects the problem and illuminates the engine light and stores the Diagnostic Trouble Code (DTC), and the ECM performs the fail-safe function and turns the other shift solenoids valves in good condition "ON/OFF".

OBDII Code P0977 Lexus - Shift Solenoid 'B' Control Circuit High - AutoCodes.com — P0977 Lexus Code - Shift Solenoid 'B' Control Circuit High

What does this mean?

What are the Possible Causes of the DTC P0977 Lexus?

Low transmission fluid level
Dirty transmission fluid
Faulty shift solenoid 'B' valve
Shift solenoid 'B' valve harness or connectors
Shift solenoid 'B' valve circuit is open or shorted

How to Fix the DTC P0977 Lexus?

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 Lexus 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.

Need more information about the P0977 Lexus code?

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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.