What it means
The control module monitors the electrical circuit for shift solenoid B. It sets this code when the circuit signal is intermittent or erratic rather than consistently present.
At a glance
- Usually lights the check-engine light
How it works
Shift solenoid B is an electrically controlled valve, and its circuit lets the control module command hydraulic flow for transmission shifts. This code sets when the module detects an intermittent or erratic signal from the solenoid B circuit rather than a steady electrical fault.
Common causes
Most likely first.
- Intermittent contact at connector
- Connector with intermittent contact under vibration
- Harness routed against vibrating component
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
- Capture freeze-frame data and review transmission codes and live solenoid B data to identify the conditions when the signal drops out.
- Inspect the solenoid B connector and harness for loose terminals, corrosion, chafing, or routing against a vibrating part.
- With the manufacturer's wiring diagram, check circuit continuity and shorts while gently moving the harness to reveal an intermittent connection.
- Use a scan tool to monitor solenoid B command and circuit status during a controlled harness wiggle test.
- If the harness and connectors pass, test the solenoid B winding when cold and after it is warm, following the manufacturer's procedure.
Common fixes
- Reseat and secure a loose solenoid B connector.
- Clean corroded terminals and restore connector seals.
- Repair chafed wiring or reroute and secure a harness contacting a vibrating component.
- Replace shift solenoid B if its signal becomes intermittent during testing.
- Repair a failed circuit connection identified by continuity testing.
Can I keep driving?
If shifts remain normal, limit driving and watch for warning lights or changing shift behavior; avoid towing and heavy acceleration until the intermittent fault is found. A dropout can cause sudden harsh shifts or limp mode.
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.