What Does P1561 Mean?
This diesel injection code indicates the actual fuel quantity delivered differs significantly from the commanded quantity. The fuel metering system is not achieving target injection amounts.
Common Causes
35%
Worn or failing fuel injectors with inconsistent delivery
30%
High-pressure fuel pump wear causing pressure fluctuations
20%
Fuel pressure regulator malfunction causing unstable rail pressure
10%
Restricted fuel filter reducing fuel supply
5%
Air in fuel system affecting delivery accuracy
Diagnostic Steps
1
Step 1: Monitor actual vs commanded fuel rail pressure during various load conditions
2
Step 2: Check fuel filter restriction using pressure gauge on inlet and outlet
3
Step 3: Perform injector balance test or cylinder contribution test
4
Step 4: Inspect for air in fuel system; check for fuel leaks at connections
5
Step 5: Evaluate high-pressure pump performance with flow and pressure tests
Estimated Repair Cost
$500 - $3,500
Parts + labor, varies by vehicle and location
This diesel injection code indicates the actual fuel quantity delivered differs significantly from the commanded quantity. The fuel metering system is not achieving target injection amounts.
The most common cause of P1561 (Quantity Adjuster Control Difference) is: Worn or failing fuel injectors with inconsistent delivery
Typical repair costs for P1561 range from $500 to $3,500, depending on the vehicle, location, and whether you do it yourself or go to a shop.
May cause poor performance, hesitation, and increased emissions. Generally safe to drive but performance will be compromised.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P1561 to identify the root cause.
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Quick Info
Category
Powertrain
System
Diesel Fuel Injection System
Difficulty
Type
Manufacturer
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