Reductant Injection Valve Circuit Low Bank 2 Unit 2
What it means
P2057 is a diesel emissions code meaning the control circuit for the reductant (DEF/urea) injection valve on bank 2, unit 2 is reading low (typically a short to ground). That injector doses diesel exhaust fluid into the SCR system to reduce NOx. The engine still starts and runs, but the emissions system can flag a warning and eventually cut power. The usual cause is a wiring short or a failed injector.
Can I keep driving? The engine still starts and drives, but a faulty DEF injector circuit raises NOx and can trigger reduced power or a limp mode — repair it before it derates.
Common symptoms
What you'll notice
- Check-engine light on
- DEF/emissions system warning message
- Possible reduced power or limp mode if it persists
- Higher NOx / failed emissions test
Common causes
Most likely first
- Short-to-ground in the reductant (DEF) injector circuit wiringLikely
- Failed reductant injection valve (DEF injector)Common
- Poor or corroded electrical connection at the injectorCommon
- Faulty DEF/emissions control module or PCMLess often
How to diagnose & fix
Work through it in order
- Read freeze-frame data to confirm the low-voltage fault on bank 2 unit 2.
- Inspect the injector wiring and connector for a short to ground or corrosion.
- Measure the injector coil resistance against spec.
- Replace the reductant injection valve if the circuit is shorted internally.
- Verify DEF dosing per the manufacturer procedure, then clear and re-test.
FAQ
Quick answers
Is it safe to drive with P2057?+
Can I just clear P2057?+
Related codes
Often seen with P2057
Read & clear P2057 yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.