P20D3 code meaning
Exhaust Aftertreatment Fuel Injector B Control Circuit Low
Powertrain system Generic code P20xx codes Check engine light
What P20D3 means
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.
P20D3 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyMedium
- Typical labor0.5 to 2.5 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P20D3
- Check engine light on
- Doser B switched off, regeneration impaired
Common causes of P20D3
- Most likelyChafed control wire to doser B touching ground
- PossibleMoisture in the doser B connector
- Less likelyInternal short in doser B
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Aftertreatment fuel injector
What each part of P20D3 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 2 | Generic code (second SAE range): it means the same on every make. |
| 0 | Area: fuel and air metering and auxiliary emission controls. |
| D3 | The exact fault in that area. |
What to do next
- Note P20D3 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P20D3
What does P20D3 mean?
P20D3 means "Exhaust Aftertreatment Fuel Injector B Control Circuit Low". The control line of the second exhaust fuel doser (B) is pulled toward ground. It is a generic code, so it means the same on every make.
Is it safe to drive with P20D3?
Drive gently and only to a workshop. With P20D3 the car can go into limp mode (reduced power) to protect itself.
Will P20D3 fail an emissions test?
Yes, it can. P20D3 is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P20D3 to fix?
Difficulty: medium. A typical repair takes 0.5 to 2.5 hours of work. This is a job for a workshop.
Will P20D3 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.