What Does P20D6 Mean?
The PCM has detected that exhaust aftertreatment fuel injector B is stuck in the closed position and cannot open to deliver fuel. This prevents proper DPF regeneration and exhaust system temperature management.
Common Causes
40%
Mechanical seizure of injector B pintle or needle valve stuck closed
30%
Carbon buildup or varnish deposits preventing injector B from opening
15%
Failed solenoid in injector B unable to generate magnetic force
10%
Contaminated fuel causing internal injector B component swelling or binding
5%
Excessive pressure or debris blocking injector B nozzle outlet
Diagnostic Steps
1
Step 1: Command injector B on with scan tool and monitor for fuel pressure drop indicating flow
2
Step 2: Check for clicking sound at injector B when commanded (indicates solenoid function)
3
Step 3: Measure injector B current draw during activation (should match specification)
4
Step 4: Remove injector B and attempt manual operation or cleaning if accessible
5
Step 5: Test injector B on flow bench to verify no flow when energized
Estimated Repair Cost
$300 - $1,500
Parts + labor, varies by vehicle and location
The PCM has detected that exhaust aftertreatment fuel injector B is stuck in the closed position and cannot open to deliver fuel. This prevents proper DPF regeneration and exhaust system temperature management.
The most common cause of P20D6 (Exhaust Aftertreatment Fuel Injector "B" Stuck Closed) is: Mechanical seizure of injector B pintle or needle valve stuck closed
Typical repair costs for P20D6 range from $300 to $1,500, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Vehicle is safe to drive short-term but DPF regeneration will fail, leading to progressive clogging and eventual engine derate or shutdown. Should be repaired promptly.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P20D6 to identify the root cause.
OBDHut Mobile App
Scan codes directly from your car with the OBDHut app.
Coming Soon
Quick Info
Category
Powertrain
System
Exhaust Aftertreatment System
Difficulty
Type
Generic (SAE)
Recommended Tools
OBD2 Scanner
A quality scan tool helps you read codes, view live data, and clear faults.
