OBD Codes

P0977

Shift Solenoid "B" Control Circuit High

Moderatetransmission

Overview

The P0977 diagnostic trouble code signals a shift solenoid "b" control circuit high condition detected by the transmission control module. This code relates to the automatic transmission system and may affect shift quality, timing, or overall transmission performance. Prompt attention is important to prevent further transmission damage.

Symptoms

  • Harsh or delayed shifting
  • Check Engine Light (MIL) illuminated
  • Vehicle stuck in one gear (limp mode)
  • Loss of one or more gears

Common Causes

  • Low or contaminated transmission fluid
  • Faulty shift solenoid or solenoid pack
  • Wiring issues in the transmission harness
  • Worn or damaged internal transmission components

Diagnosis Steps

  1. 1Connect an OBD-II scanner and read all stored trouble codes and freeze frame data
  2. 2Check transmission fluid level and condition; top off or replace if needed
  3. 3Test the transmission speed sensors with a multimeter or scan tool
  4. 4Inspect wiring and connectors for the transmission harness
  5. 5Perform a transmission pressure test if accessible

Estimated Repair Cost

$300$2,500

Cost varies by vehicle, location, and repair shop. Includes parts and labor.

Commonly Affected Vehicles

Toyota CamryFord F-150Nissan RogueChevrolet Silverado

Related Codes

More Transmission Codes

Frequently Asked Questions

Driving with a transmission code is risky. Continued driving can cause further damage to the transmission, resulting in significantly higher repair costs. Have it inspected as soon as possible.