P2049

Reductant Injection Valve Circuit High Bank 1 Unit 1

Q: Is it safe to drive with P2049?

Short-term usually, but the SCR system may derate engine power to protect emissions. Repair it before the vehicle limits performance or restart attempts.

Q: Can I just clear P2049?

It returns until the wiring or injector fault is repaired, and clearing won't prevent an emissions-related derate from recurring.

Diesel exhaust aftertreatment (SCR) Generic OBD-II Medium

What it means

P2049 means the aftertreatment controller detected higher-than-expected voltage in the reductant (DEF) injection valve circuit for bank 1, unit 1. This valve sprays diesel exhaust fluid into the exhaust to cut NOx. A high-circuit fault is usually an open or high-resistance wiring problem or a failed injector, and can trigger a power derate to keep emissions in check.

Medium

Can I keep driving? Usually driveable at first, but many diesels reduce power (derate) when reductant dosing fails — repair it before the vehicle limits performance.

Real-world scan data

Seen in

scans in the past year

Found in

<0.1%

of scans

<0.1%

of scans that found faults

Figures reflect only diagnostic scans recorded through our own apps and tools. Cars are typically scanned because a symptom or warning light prompted it, so these counts describe our scan records — not the incidence of faults in any model, and not the quality, reliability, or safety of any vehicle. No comparison between manufacturers or models is implied. All trademarks belong to their respective owners; no affiliation or endorsement is implied.

Common symptoms

What you'll notice

Check-engine light on
SCR / DEF or emissions-system warning message
Possible reduced power (engine derate)
Increased NOx / failed emissions readiness

Common causes

Most likely first

Open circuit or high resistance in the reductant injection valve wiringLikely
Failed reductant (DEF) injection valveCommon
Corroded or loose connector at the injectorCommon
Faulty PCM/aftertreatment control module — less commonLess often

How to diagnose & fix

Work through it in order

Read freeze-frame data and inspect the reductant injector connector and wiring for an open or high resistance.
Check the injector's supply and control circuits with a multimeter for continuity.
Measure the reductant injection valve resistance against spec and replace it if out of range.
If wiring and injector are good, have the aftertreatment control module evaluated. Clear and re-test.

FAQ

Quick answers

Is it safe to drive with P2049?+

Short-term usually, but the SCR system may derate engine power to protect emissions. Repair it before the vehicle limits performance or restart attempts.

Can I just clear P2049?+

It returns until the wiring or injector fault is repaired, and clearing won't prevent an emissions-related derate from recurring.

Read & clear P2049 yourself

Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.

▶ Get it on Google Play

✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX