Transmission

P0976 — Shift Solenoid B Control Circuit Low

Severity: medium Drive with care, to a shop

What P0976 means

P0976 means the transmission control module (TCM or PCM) detected abnormally low voltage in the shift solenoid B control circuit, usually from a short to ground. Solenoids in the valve body direct fluid to the clutches on command to change gears. When the circuit does not behave as expected, the module cannot control shifting properly.

Symptoms

  • Harsh or jerky shifts, especially in 2nd gear
  • Transmission warning or Check Engine light on
  • Transmission stuck in one gear (limp mode)
  • Failure to upshift or downshift
  • Reduced fuel economy

Possible causes

  1. Failed shift solenoid B (internal winding short)
  2. Wiring harness shorted to ground
  3. Chafed or damaged wire insulation near the valve body
  4. Corroded or damaged valve body connector
  5. Faulty TCM or PCM
  6. Transmission fluid or moisture contaminating the connector

How to diagnose

  1. Read all codes and freeze frame data, clear the code and see if it returns
  2. Check transmission fluid level and condition, and look for metal debris
  3. Inspect the harness and transmission connector for chafing, fluid and corrosion
  4. Measure solenoid B resistance and compare it to the manufacturer spec
  5. Check the control wire for a short to ground with the connector unplugged
  6. Verify power and ground at the solenoid with a multimeter
  7. Command the solenoid on with a scan tool to test its operation
  8. If wiring and solenoid test good, evaluate the TCM/PCM

Common fixes

  • Replace solenoid B or the solenoid pack
  • Repair or replace the damaged section of harness
  • Clean or replace the valve body connector
  • Change the fluid and filter if contaminated
  • Replace or reprogram the control module if confirmed faulty

Questions and answers

What does P0976 mean?

The control module detected a low signal in the shift solenoid B circuit. The usual causes are a failed solenoid or a wire shorted to ground.

Can I drive with P0976?

Only briefly and carefully, to a shop. The transmission may go into limp mode, and harsh shifts can damage the clutches.

How do I fix P0976?

Check the fluid, harness and connector first, then test the solenoid resistance. Replacing the solenoid or repairing the wiring fixes most cases.

This is general information about the code. The meaning can differ between makes and models: a scan tool and the repair manual for your car will show the exact cause.