P20D3Exhaust Aftertreatment Fuel Injector B Control Circuit Low
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- The control line of the second exhaust fuel doser (B) is pulled toward ground. No manufacturer documents P20D3 publicly. For injector A, GM's diesel tables detect this by a switched-off output voltage below about 2 V and treat it as Type A with the MIL after one trip (P20CD), because a grounded line can open the valve without command. A similar strict rating is likely for B. CARB requires each electrical part of an in-exhaust injection system to be checked for circuit faults. The open circuit is P20D1, the short to power P20D4. Only engines with two dosing points can set this code.
- What you may notice
- Check engine light on
- Doser B switched off, regeneration impaired
- Likely causes
- LikelyChafed control wire to doser B touching ground
- PossibleMoisture in the doser B connector
- RareInternal short in doser B
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Usually a job for a workshop.Typical cost: €100 – €900
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.