What it means
A control module has detected that the software in gear shift control module B is incompatible with its own software or configuration. Gear-selection functions may be affected; the specific effects depend on the vehicle.
How it works
Gear Shift Control Module B manages a gear-selection function defined by the vehicle’s design. This code sets when another module detects that module B’s software or configuration is incompatible with its own, which may interfere with gear selection or related transmission functions.
Common causes
Most likely first.
- Incorrect or incompatible gear shift control module B software
- Module replacement without required programming or configuration
- Incorrect module part number
Symptoms
- Multiple warning lights may illuminate
- Affected modules may go into limp mode or shut down
- Specific functions inoperative depending on module
- Diagnostic tools may show communication faults
How to diagnose it
- Scan the transmission and related modules, recording freeze-frame data and communication, gear-selection, or configuration codes.
- Note whether the problem began after module B replacement, transmission work, or programming.
- Read Gear Shift Control Module B’s part number, software identity, and configuration, and compare them with vehicle-specific service information.
- Inspect module B’s connectors, power and ground connections, and network wiring for looseness, corrosion, or damage.
- Verify the module’s compatibility and required setup using the manufacturer’s procedure before assessing transmission operation.
Common fixes
- Repair a loose or corroded module B connection.
- Complete the required gear-shift module configuration or relearn.
- Program compatible software into Gear Shift Control Module B.
- Replace an incorrect-part-number module B with a compatible unit and perform required programming.
Can I keep driving?
Do not drive if the vehicle cannot select or hold the intended gear, shifts unpredictably, or displays a transmission warning with abnormal operation. If gear selection remains normal, limit driving and avoid towing or hard acceleration until the fault is diagnosed.
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.