What Does P2056 Mean?
The PCM has detected an open circuit or complete lack of continuity in the reductant injection valve circuit for Bank 2, Unit 2. This indicates the control circuit is broken, disconnected, or the injector has failed internally on the second bank.
Common Causes
35%
Faulty reductant injection valve with internal open circuit
30%
Damaged, corroded, or disconnected wiring harness to the injection valve
20%
Corroded or loose electrical connector at Bank 2 injection valve
10%
Failed DEF system control module or driver circuit for Bank 2
5%
Blown fuse or open relay in Bank 2 injection circuit
Diagnostic Steps
1
Step 1: Visually inspect Bank 2 reductant injection valve connector for damage or corrosion
2
Step 2: Check continuity of wiring from control module to Bank 2 injection valve
3
Step 3: Measure resistance of Bank 2 injection valve solenoid and compare to specification
4
Step 4: Verify power and ground signals at injection valve connector during operation
5
Step 5: Replace Bank 2 injection valve if circuits are intact but valve shows open circuit
Estimated Repair Cost
$300 - $1,200
Parts + labor, varies by vehicle and location
The PCM has detected an open circuit or complete lack of continuity in the reductant injection valve circuit for Bank 2, Unit 2. This indicates the control circuit is broken, disconnected, or the injector has failed internally on the second bank.
The most common cause of P2056 (Reductant Injection Valve Circuit/Open Bank 2 Unit 2) is: Faulty reductant injection valve with internal open circuit
Typical repair costs for P2056 range from $300 to $1,200, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Not immediately dangerous but will cause emissions system failure. May result in reduced engine power or speed limiting if not repaired within specified timeframe.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P2056 to identify the root cause.
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Quick Info
Category
Powertrain
System
Emissions Control System (SCR/DEF)
Difficulty
Type
Generic (SAE)
Recommended Tools
OBD2 Scanner
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