What Does P2051 Mean?
The ECM detects abnormally low voltage or current in the reductant injector circuit for Bank 2 Unit 1. This indicates a short to ground, partial short, or excessive resistance affecting injector operation.
Common Causes
35%
Short to ground in reductant injector wiring harness
30%
Faulty reductant injector with internal short or low resistance coil
20%
Damaged injector connector causing short circuit
10%
Water or DEF contamination in injector connector creating ground path
5%
ECM driver circuit malfunction
Diagnostic Steps
1
Step 1: Disconnect reductant injector and inspect connector for moisture, corrosion, or DEF crystallization
2
Step 2: Measure injector coil resistance with injector disconnected (verify against specifications)
3
Step 3: Test wiring harness for short to ground using multimeter on both control and power circuits
4
Step 4: Check for proper ground circuit integrity at ECM and injector ground points
5
Step 5: Replace injector if resistance is below specification or wiring shows no faults
Estimated Repair Cost
$250 - $1,200
Parts + labor, varies by vehicle and location
The ECM detects abnormally low voltage or current in the reductant injector circuit for Bank 2 Unit 1. This indicates a short to ground, partial short, or excessive resistance affecting injector operation.
The most common cause of P2051 (Reductant Injection Valve Circuit Low Bank 2 Unit 1) is: Short to ground in reductant injector wiring harness
Typical repair costs for P2051 range from $250 to $1,200, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Vehicle may experience reduced power and emissions warnings. Continued operation may lead to engine derate or shutdown per EPA regulations.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P2051 to identify the root cause.
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Quick Info
Category
Powertrain
System
Selective Catalytic Reduction (SCR) Emissions System
Difficulty
Type
Generic (SAE)
Recommended Tools
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