What it means
The B-channel actuator of the transmission range control reports a circuit high condition. Gear-selector mechanical engagement cannot be requested as expected.
At a glance
- Usually lights the check-engine light
- The engine or gearbox may go into limp mode
How it works
The transmission range control B actuator operates a mechanical part of the gear-selection system. The transmission control module monitors the B actuator circuit and sets this code when the circuit voltage is higher than expected, which can prevent the requested engagement.
Common causes
Most likely first.
- Control wire shorted to B+
- Open actuator coil
- Connector pins corroded - high contact resistance
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
- Save freeze-frame data and review transmission live data for the commanded range and B actuator status to identify when the high reading occurs.
- Check for limp mode and compare the selected gear range with the range reported by the transmission module.
- Inspect the B actuator connector and harness for corrosion, loose or backed-out terminals, damaged insulation, or contact with a power wire.
- Check the B actuator coil for an open circuit using the manufacturer's specification and the vehicle wiring diagram.
- Test the B control wire for a short to battery voltage and inspect connector continuity using the manufacturer's procedure.
Common fixes
- Clean and secure corroded or loose B actuator connector terminals.
- Repair wiring shorted to battery voltage in the B control circuit.
- Replace the B actuator if its coil is open.
- Clear the code and confirm B-channel operation with the specified transmission checks.
Can I keep driving?
Avoid driving if shifts are missing, slipping, or harsh, or if the vehicle is stuck in one gear; continuing can worsen transmission damage. If shifting remains normal, keep trips short and avoid heavy loads until the circuit is checked.
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.