What Does P20D3 Mean?
The PCM has detected voltage in the exhaust aftertreatment fuel injector B control circuit that is below the expected range. This indicates a short to ground or excessive resistance in the circuit.
Common Causes
40%
Short to ground in injector B wiring harness or connector
30%
Internal short to ground within exhaust fuel injector B
15%
Chafed or damaged wiring rubbing against chassis or exhaust components
10%
Water intrusion or corrosion causing short circuit in connector
5%
PCM internal driver circuit malfunction pulling voltage low
Diagnostic Steps
1
Step 1: Disconnect injector B connector and measure resistance to ground on both injector and harness sides
2
Step 2: Inspect wiring harness routing for contact with hot exhaust components or sharp edges
3
Step 3: Check for water or corrosion inside injector B connector and PCM connector
4
Step 4: Measure injector B coil resistance and compare to specification (should not show near-zero resistance)
5
Step 5: Use oscilloscope to monitor injector control circuit voltage pattern during commanded operation
Estimated Repair Cost
$150 - $1,300
Parts + labor, varies by vehicle and location
The PCM has detected voltage in the exhaust aftertreatment fuel injector B control circuit that is below the expected range. This indicates a short to ground or excessive resistance in the circuit.
The most common cause of P20D3 (Exhaust Aftertreatment Fuel Injector "B" Control Circuit Low) is: Short to ground in injector B wiring harness or connector
Typical repair costs for P20D3 range from $150 to $1,300, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Vehicle is safe to drive but DPF regeneration will not function properly, leading to potential clogging and reduced engine performance over time. No immediate danger.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P20D3 to identify the root cause.
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Quick Info
Category
Powertrain
System
Exhaust Aftertreatment System
Difficulty
Type
Generic (SAE)
Recommended Tools
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