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Home / DTC / P2049 — Reductant Injection Valve Circuit High Bank 1 Unit 1

P2049 — Reductant Injection Valve Circuit High Bank 1 Unit 1

Detailed page for trouble code P2049.

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P2049

Generic P — Powertrain

Reductant Injection Valve Circuit High Bank 1 Unit 1

Brand: Generic
Type: P — Powertrain
Views: UK: 5 EN: 16 RU: 22
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Page language: EN

Causes

  • Open or damaged wiring in reductant injector control circuit (broken conductor, chafing)
  • Short to battery (B+) on the injector control lead
  • Corroded or loose connector at the reductant injection valve
  • Failed reductant injection valve (internal short or open)
  • Blown or corroded fuse or faulty relay powering the injector circuit
  • Poor ground at valve or ECM/PCM

Symptoms

  • Malfunction indicator lamp (MIL) or DTC P2049 stored
  • Reduced or inhibited reductant dosing, increased NOx emissions
  • Possible limp mode or reduced engine power depending on manufacturer strategy
  • Reduced effectiveness of SCR system and possible DPF/aftertreatment warnings
  • Engine may run normally otherwise; fault is electrical

What to check

  • Read freeze frame and live data with a scan tool (reductant injector status, commanded duty, system voltage)
  • Visually inspect injector connector, wiring harness along frame and engine for damage or rubbing
  • Inspect fuses and relays related to reductant injection and replace if suspect
  • Back-probe injector connector and measure voltage with key ON and while commanding injector ON/OFF
  • Measure injector coil resistance with connector disconnected
  • Perform wiggle test on harness while monitoring live data for intermittent faults

Signal parameters

  • Resting control line voltage with valve disconnected: near battery voltage if circuit is pulled-up, or within expected reference range for vehicle
  • Commanded duty cycle or ON/OFF state as shown by scan tool (0–100% for pulse-width controlled valves)
  • Injector coil resistance (typical solenoid valves commonly 2–30 ohms; consult vehicle spec)
  • Injector current when commanded ON (often 0–2 A depending on valve design)
  • Short-to-battery condition: control line reads battery voltage regardless of commanded state

Diagnostic algorithm

  1. Retrieve full freeze frame data and any related DTCs. Note battery voltage and system state when code set.
  2. Visually inspect reductant injector connector, harness, and nearby wiring for damage, corrosion, or fluid contamination. Repair obvious issues.
  3. With IGN ON (engine OFF) and connector connected, back-probe the injector control wire and monitor voltage. Command injector ON via scan tool and observe changes. A 'high' fault usually shows battery voltage at the control line regardless of command.
  4. Disconnect the injector connector and measure resistance of the injector coil to ground with a multimeter. Compare to manufacturer spec. An open or shorted coil indicates a failed valve.
  5. Check for short-to-B+ by measuring continuity between control wire and battery positive with harness disconnected. No continuity should exist. If continuity present, locate and repair short.
  6. Inspect and test associated fuses and relays. Replace as required.
  7. Check ground points for good connection and low resistance. Repair any poor grounds.
  8. If wiring and valve tests good, test the ECM/PCM driver output. If driver is suspected failed, verify with a known-good module or follow manufacturer procedures before replacement.
  9. Clear codes, perform a functional test of reductant dosing, and verify code does not return under the same conditions.

Likely causes

  • Connector corrosion or disconnected harness at the reductant injector
  • Broken or pinched wire causing open/short to battery
  • Failed reductant injection valve (stuck open or internal electrical fault)
  • Fuse or relay supplying the valve circuit is faulty

Fault status

⚠️ Status
Reductant Injection Valve Circuit High – Bank 1 Unit 1 (electrical high voltage detected on injector control circuit)
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1.0-2.5 hours

Similar codes

P2048 P204A P20E0 P0201 P0200
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