What it means
Reductant Injection Valve Circuit High (Bank 1 Unit 2): the signal voltage is above the expected range. This valve doses reductant (DEF/AdBlue) into the exhaust for SCR NOx reduction.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
The reductant injection valve for Bank 1, Unit 2 meters DEF/AdBlue into the exhaust so the SCR system can reduce NOx. The control module monitors the valve circuit and sets P2055 when its signal voltage is higher than the expected range, often because the circuit is shorted to battery voltage.
Common causes
Most likely first.
- Short to B+
- Connector pins corroded - high contact resistance
- Supply wire pinched against B+ source
Symptoms
- Check engine light or NOx warning on
- AdBlue/DEF level or quality warning
- Possible no-start countdown after ignore period
- Failed emissions inspection (NOx)
How to diagnose it
- Record freeze-frame data and check reductant-system live data for the Bank 1 Unit 2 valve command and any related circuit codes.
- With the ignition off, inspect the Bank 1 Unit 2 valve connector and nearby harness for corrosion, damaged insulation, or a wire pinched against a power source.
- Check the connector terminals for corrosion, looseness, or poor contact that could raise resistance.
- Use the wiring diagram to test the valve control circuit for an unintended connection to battery voltage, following the manufacturer's procedure.
- If the wiring checks out, test the valve and its circuit against the manufacturer's specification before replacing a component.
Common fixes
- Repair or reroute wiring pinched against a power source.
- Clean or repair corroded or loose connector terminals.
- Repair a control wire shorted to battery voltage.
- Replace the Bank 1 Unit 2 reductant injection valve if it fails the specified test.
Can I keep driving?
You can usually drive cautiously if the vehicle has no other symptoms, but the SCR system may not control NOx emissions correctly. Check the DEF/AdBlue warnings and any start countdown; continued driving can lead to an emissions failure or a no-start restriction.
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.