Reductant Injector Circuit Low (Bank 1 Unit 1)
The P2048 code means the vehicle's onboard diagnostic system has detected: Reductant Injector Circuit Low (Bank 1 Unit 1). This is a serious severity code.
- Keep driving?
- Short distances only
- DIY difficulty
- hard
- Estimated cost
- $300 - $900 (parts and labor)
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What Are the Symptoms of P2048?
- Check Engine Light illuminated
- DEF system fault warning
- SCR system not functioning
- Engine power may be reduced
- Possible speed limiter activation
What Causes P2048? (Most Likely First)
- Short to ground in DEF injector circuit Very High
- Failed DEF injector coil High
- Water intrusion in injector connector Moderate
- Damaged wiring shorted to chassis Moderate
- PCM driver circuit fault Low
Can I Still Drive with P2048?
Short distances only. P2048 is rated serious severity. Keep trips short and get it diagnosed soon rather than waiting for symptoms to worsen.
Frequently Asked Questions
What does P2048 mean?
P2048 indicates the DEF injector circuit has a low voltage condition, usually from a short to ground in the wiring or a failed injector coil.
Can I drive with a P2048 code?
Short-distance driving only. The SCR system is not functioning, and a speed limiter may be activated on many modern diesel vehicles.
How much does it cost to fix P2048?
Expect $300 to $900 for DEF injector replacement or wiring repair.
Mechanics Guide Step-by-step diagnosis
How Do You Diagnose P2048?
-
Read freeze frame data for P2048
-
Inspect DEF injector connector for water damage
-
Measure injector circuit for shorts to ground
-
Test injector coil resistance
Sources 2
This page is built from documented references. Verify against your own service info before repair work.
- SAE J2012Diagnostic Trouble Code Definitions (defines the generic OBD-II code ranges)
- Cross-checked against the SAE J2012:2002 DTC table (2026-08-27)archived scan of the SAE standard — readable copy, not SAE’s current edition
P2048 on Diesel, EV & Equipment
The same code ID appears across other engines and platforms. The diagnostic flow varies by manufacturer — these are the platform-specific breakdowns:
Which Vehicles Commonly Get P2048?
- 2012-2018 BMW 328d 2.0L Diesel
- 2010-2016 Mercedes-Benz ML350 3.0L BlueTEC
- 2014-2020 Ram 3500 6.7L Cummins
- 2011-2017 Ford F-350 6.7L Power Stroke
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