P2056 code meaning
Reductant Injection Valve Circuit/Open (Bank 2 Unit 2)
Powertrain system Generic code P20xx codes Check engine light
What P2056 means
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.
P2056 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyMedium
- Typical labor0.5 to 3 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P2056
- MIL on
- Reduced NOx conversion on Bank 2
Common causes of P2056
- Most likelyConnector of the Bank 2 second injector unplugged or corroded
- PossibleBroken wire in the Bank 2 dosing harness
- PossibleOpen injector coil
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Reductant injection valve
What each part of P2056 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 2 | Generic code (second SAE range): it means the same on every make. |
| 0 | Area: fuel and air metering and auxiliary emission controls. |
| 56 | The exact fault in that area. |
What to do next
- Note P2056 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P2056
What does P2056 mean?
P2056 means "Reductant Injection Valve Circuit/Open (Bank 2 Unit 2)". P2056 refers to the fourth possible DEF injector position: the second valve in the Bank 2 exhaust line. It is a generic code, so it means the same on every make.
Is it safe to drive with P2056?
Drive gently and only to a workshop. With P2056 the car can go into limp mode (reduced power) to protect itself.
Will P2056 fail an emissions test?
Yes, it can. P2056 is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P2056 to fix?
Difficulty: medium. A typical repair takes 0.5 to 3 hours of work. This is a job for a workshop.
Will P2056 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.