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Home / DTC / P2048 — Reductant Injection Valve Circuit Low Bank 1 Unit 1

P2048 — Reductant Injection Valve Circuit Low Bank 1 Unit 1

Detailed page for trouble code P2048.

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Code

P2048

Generic P — Powertrain

Reductant Injection Valve Circuit Low Bank 1 Unit 1

Brand: Generic
Type: P — Powertrain
Views: UK: 11 EN: 22 RU: 23
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Page language: EN

Causes

  • Open or high-resistance wiring in the reductant injector circuit
  • Short to ground in the injector wiring
  • Corroded, damaged or disconnected connector at the injector
  • Failed reductant injection valve (stuck or electrically open)
  • Blown fuse or faulty relay supplying the injector circuit
  • Faulty ground or poor chassis ground connection

Symptoms

  • MIL/Check Engine light illuminated
  • Reduced or disabled reductant dosing and possible increased NOx emissions
  • Reduced aftertreatment performance or active regeneration inhibited
  • Diagnostic trouble code stored for reductant circuit
  • Possible limp or reduced-emissions control mode depending on manufacturer

What to check

  • Read and record all stored/relevant codes and freeze-frame data with a scan tool
  • Visually inspect injector, connector and wiring for corrosion, damage, water ingress, pins pushed out or bent
  • Check fuse(s) and relay(s) for the reductant injection circuit
  • Verify battery voltage and charging system are within specification
  • Back-probe the injector connector and measure supply and control signals with key ON and while commanding injector ON from a scan tool
  • Measure injector coil resistance with the connector disconnected

Signal parameters

  • Supply voltage to injector: approx. battery voltage (~11–14.5 V) with key ON/engine running (manufacturer-specific)
  • Injector coil resistance (typical range): usually low single digits to a few tens of ohms — consult OEM spec; unexpected open/infinite or very high resistance indicates bad coil/wiring
  • When commanded ON: control driver will either switch ground or supply—expect voltage change on the control pin (use scan tool to command while probing)
  • If PWM-controlled: duty cycle varies with command; frequency often in the tens to low hundreds of Hz (manufacturer-specific)
  • No sustained current draw exceeding part specification; excessive current indicates shorted coil or wiring

Diagnostic algorithm

  1. Confirm code P2048 and note freeze-frame/conditions. Clear code and attempt to re-create fault to confirm persistence.
  2. Perform careful visual inspection of the injector, connector, and harness for contamination, corrosion, damage, or pin issues.
  3. Check fuses/relays related to reductant dosing circuit; replace if blown and re-test.
  4. With connector disconnected, measure injector coil resistance. If open or out of spec, replace injector.
  5. Back-probe connector with harness connected. With key ON, verify supply voltage to injector power pin ~battery voltage. If absent, trace supply/fuse/relay.
  6. Command injector ON with a scan tool while monitoring the control pin. Verify the control pin changes (ground switching or supply switching as designed). If no change, trace continuity to the control module and check module outputs.
  7. Perform continuity and short-to-ground tests on wiring between the injector connector and the control module. Repair any opens/shorts.
  8. If wiring and injector test good, evaluate control module driver: check for proper output using oscilloscope while commanding; if driver does not switch and wiring is good, consider ECM/reductant module repair or replacement after OEM verification/TSB checks.
  9. After repairs, clear codes and road-test/operate system through several cycles to confirm code does not return. Check for any available software updates or TSBs related to reductant control.

Likely causes

  • Damaged or corroded connector at the reductant injector
  • Open or shorted wiring between injector and control module
  • Failed reductant injection valve coil
  • Blown fuse or failed relay for reductant circuit
  • Control module driver failure (less common)

Fault status

⚠️ Status
Reductant injection valve circuit low — Bank 1 Unit 1 (low voltage/low signal detected).
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1.0-3.0 hours

Similar codes

P2047 P2049 P20E8 P20E9
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