What it means
The control module detects a low electrical level in the shift solenoid B control circuit.
At a glance
- Usually lights the check-engine light
How it works
Shift solenoid B is an electrically operated valve that routes transmission fluid to help change gears. The control module monitors the electrical level in the B control circuit and sets P0976 when that level is lower than expected. A short to ground, chafed wiring, or poor connector contact can pull the circuit low.
Common causes
Most likely first.
- Short to ground
- Connector pins corroded - high contact resistance
- Harness chafing through insulation
Symptoms
- Check engine or transmission warning light on
- Harsh, delayed, or missing shifts
- Possible limp mode (locked in one gear)
- Slipping or shuddering during gear changes
How to diagnose it
- Record freeze-frame data and check live transmission data to see when the solenoid B circuit fault occurred.
- Inspect the B circuit harness for chafing or crushed sections that may expose the control wire.
- Check solenoid B connector pins for corrosion, looseness, or poor contact that could lower the signal.
- Following the wiring diagram, test the B control wire for a short to ground and check its condition along the harness.
- Test solenoid B and its connections against the manufacturer’s specification to determine whether the fault is in the component or circuit.
- Consider the transmission control module only after wiring, connector, and solenoid checks pass.
Common fixes
- Clean or repair corroded or loose terminals at the solenoid B connector.
- Repair chafed insulation or a B control wire shorted to ground.
- Replace shift solenoid B if it fails the specified electrical test.
- Repair or replace the transmission control module if testing confirms an internal fault.
Can I keep driving?
Avoid hard acceleration and long trips if shifting is abnormal, and stop if the transmission slips or loses drive. Continued driving with a low solenoid B circuit can lead to poor shifts and additional transmission wear.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.