P20D2 code meaning
Exhaust Aftertreatment Fuel Injector B Control Performance
Powertrain system Generic code P20xx codes Check engine light
What P20D2 means
With its wiring intact, the second exhaust fuel doser (B) is not delivering what was asked for: too little heat appears across the catalyst during dosing, or heat appears when it should be idle. No manufacturer documents P20D2 publicly. The comparable check for injector A on GM's 6.6 L Duramax (P20CC, 15OBDG09) watches for the catalyst outlet running far hotter than its inlet outside regeneration. CARB requires a malfunction whenever the injection system can no longer bring about regeneration, and a feedback-control fault if the system runs out of adjustment. Stuck positions of doser B are P20D5 and P20D6, the electrical faults P20D1, P20D3 and P20D4.
P20D2 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyHard
- Typical labor1 to 3 hours
- Clears after repairAfter a drive cycle
Symptoms of P20D2
- Check engine light on
- Longer or more frequent regenerations
- Higher fuel consumption
Common causes of P20D2
- Most likelyPartly coked nozzle on doser B
- PossibleLow or unstable fuel pressure feeding doser B
- Less likelyExhaust temperature sensor reading wrong
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 P20D2 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. |
| D2 | The exact fault in that area. |
What to do next
- Note P20D2 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 P20D2
What does P20D2 mean?
P20D2 means "Exhaust Aftertreatment Fuel Injector B Control Performance". With its wiring intact, the second exhaust fuel doser (B) is not delivering what was asked for: too little heat appears across the catalyst during dosing, or heat appears when it should be idle. It is a generic code, so it means the same on every make.
Is it safe to drive with P20D2?
Drive gently and only to a workshop. With P20D2 the car can go into limp mode (reduced power) to protect itself.
Will P20D2 fail an emissions test?
Yes, it can. P20D2 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 P20D2 to fix?
Difficulty: hard. A typical repair takes 1 to 3 hours of work. This is a job for a workshop.
Will P20D2 clear itself after the repair?
After the repair the car has to complete a drive cycle (a mix of city and highway driving) before the test runs again. Until then the readiness monitor shows "not ready", which can fail an inspection.