P2DA2Gear Shift Control Module B Supply Voltage High
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Can trigger limp mode
- How the car detects it
- P2DA2 is the over-voltage counterpart of P2DA1: gear shift control module B, the second selector unit of a shift-by-wire system, sees a supply above its permitted maximum. No manufacturer documents P2DA2 publicly or names the limit. Excess voltage usually comes from the charging side – a failed alternator regulator or DC/DC converter, a 24 V jump start, a battery charger left connected during diagnosis – and only rarely from a short between the module feed and a higher-voltage circuit. To protect itself the module may stop accepting inputs. Allison's 6th-generation controls show that a second selector is handled as a unit of its own with separate codes, so a fault there need not disable the first one. Measure charging voltage before replacing anything.
- What you may notice
- Shifter warning in the instrument cluster
- Second selector does not respond, main selector may still work
- Further overvoltage codes in other modules, flickering lights
- Likely causes
- LikelyAlternator regulator or DC/DC converter delivering too much voltage
- PossibleJump start with 24 V or charger connected during operation
- RareModule feed shorted to a circuit with higher voltage
- RareVoltage measurement inside module B faulty
- Repair
- Medium · Often possible to do yourself.Typical cost: €20 – €700
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.