P2054
Reductant Injection Valve Circuit Low Bank 1 Unit 2
Emissions (SCR / DEF after-treatment)
Generic OBD-II
Medium
What it means
P2054 means the second reductant (diesel-exhaust-fluid) injection valve on bank 1 is reporting an abnormally low circuit voltage, so the SCR system can't meter DEF into the exhaust properly. The engine still starts and runs, but NOx emissions rise and many diesels start a derate countdown. It's usually a shorted injector, wiring, or connector fault.
Medium
Can I keep driving? The engine runs and starts normally, but the SCR system can't dose DEF properly and some diesels derate power — repair it promptly.
Common symptoms
What you'll notice
- Check-engine light on
- SCR / diesel-exhaust-fluid (DEF) system warning
- Higher NOx emissions; may fail an emissions test
- Speed / power derate if the fault persists (varies by vehicle)
Common causes
Most likely first
- Reductant (DEF) injection valve on bank 1 unit 2 shorted or open (reads low)Likely
- Injector control wiring shorted to groundCommon
- Corroded or loose connector at the injection valveCommon
- Failed reductant injection valveLess often
- Dosing control module / PCM fault (least likely)Less often
How to diagnose & fix
Work through it in order
- Read freeze-frame data and check for companion injector codes (P2053, P2055).
- Inspect the injection-valve connector and wiring for a short to ground or corrosion.
- Measure the injector's resistance against spec; a low reading points to a shorted valve.
- Replace the reductant injection valve if faulty, then clear and re-test the SCR system.
FAQ
Quick answers
Is it safe to drive with P2054?+
The engine drives fine, but the SCR system may stop dosing DEF and many diesels begin a derate countdown. Fix it before the vehicle limits power or speed.
Can I just clear P2054?+
It returns until the injection valve or wiring is repaired, and clearing won't prevent an emissions derate from recurring.
Related codes
Often seen with P2054
Read & clear P2054 yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.
✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX