What it means
The transmission control module monitors the supply voltage to gear shift control module B. This code sets when that voltage exceeds the module’s calibrated operating range.
At a glance
- Usually lights the check-engine light
- The engine or gearbox may go into limp mode
How it works
The transmission control module supplies and monitors the power feed to gear shift control module B. P2DA2 sets when the reported feed voltage is above that module’s calibrated operating range, which can disrupt gear-selection control.
Common causes
Most likely first.
- Alternator overvoltage
- Wire shorted to B+
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 supply-voltage data for gear shift control module B to see whether the high reading is present now or occurred only under particular conditions.
- Check the vehicle’s charging-system data for evidence of alternator overvoltage, since excessive system voltage can raise the module’s supply.
- With the vehicle powered down as specified by the manufacturer, inspect module B’s connector and supply wiring for damage, corrosion, loose terminals, or contact with a B+ source.
- Use the wiring diagram to test the supply circuit for a short to B+ and compare circuit readings with the manufacturer’s specification.
- If the supply and wiring are correct, check the module connector terminals and have the control module evaluated according to the manufacturer’s procedure.
Common fixes
- Repair damaged wiring or connector terminals in the module B supply circuit.
- Correct an alternator or charging-system overvoltage fault.
- Replace a blown fuse or repair a poor connection if testing identifies one.
- Replace or reprogram gear shift control module B if circuit and charging checks pass and its self-diagnostics identify an internal fault.
Can I keep driving?
Avoid towing, hard acceleration, and continued driving if shifts are harsh, slipping, or the transmission enters limp mode; arrange a safe stop if gear control becomes unpredictable. Excess voltage or impaired shifting can worsen transmission operation.
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.