P2056Reductant Injection Valve Circuit/Open (Bank 2 Unit 2)
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- P2056 refers to the fourth possible DEF injector position: the second valve in the Bank 2 exhaust line. It requires both a twin-bank layout and two dosing points per bank, a combination hardly any production engine uses; no manufacturer publicly documents the code. Detection would resemble GM's open-load check for metering valve 2 in its 2025 table (P2053): driver status read every 100 ms, more than 11 V on board, 30 bad samples out of 60, Type A. CARB lists reductant system valves among the electrical components whose circuits the OBD system has to verify. Before condemning a part, confirm which physical injector the scan tool assigns to Bank 2, unit 2, because confusing banks and units is an easy way to replace the wrong valve.
- What you may notice
- MIL on
- Reduced NOx conversion on Bank 2
- Likely causes
- LikelyConnector of the Bank 2 second injector unplugged or corroded
- PossibleBroken wire in the Bank 2 dosing harness
- PossibleOpen injector coil
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Usually a job for a workshop.Typical cost: €80 – €900
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.