P20DD code meaning
Exhaust Aftertreatment Fuel Pressure Sensor Circuit
Powertrain system Generic code P20xx codes Check engine light
What P20DD means
The pressure sensor in the feed line of the exhaust doser lets the control unit meter fuel and spot a stuck valve or plugged nozzle. This code is the general circuit fault of that sensor; signal too low, too high and unsteady have their own codes (P20DF, P20E0, P20E1). Volvo and Mack store it as P20DD13 (open circuit) and issued bulletins for Mack TD with MP10 and Volvo VNL/VNX with the D16 engine, where an internally failed AHI harness sets it together with P249F00 and P113413; the harness is replaced. Guide KC-2157 points to the sensor's wiring and connector. With no valid pressure reading, dosing and regeneration are blocked.
P20DD 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 P20DD
- Check engine light on
- Active regeneration blocked
- Further codes for the reference voltage or the dosing system
Common causes of P20DD
- Most likelyInternally damaged harness to the dosing module and its sensor
- PossibleLoose or corroded sensor connector
- Less likelyFailed pressure sensor
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Aftertreatment fuel pressure sensor
What each part of P20DD 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. |
| DD | The exact fault in that area. |
What to do next
- Note P20DD 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 P20DD
What does P20DD mean?
P20DD means "Exhaust Aftertreatment Fuel Pressure Sensor Circuit". The pressure sensor in the feed line of the exhaust doser lets the control unit meter fuel and spot a stuck valve or plugged nozzle. It is a generic code, so it means the same on every make.
Is it safe to drive with P20DD?
Drive gently and only to a workshop. With P20DD the car can go into limp mode (reduced power) to protect itself.
Will P20DD fail an emissions test?
Yes, it can. P20DD 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 P20DD to fix?
Difficulty: medium. A typical repair takes 0.5 to 2.5 hours of work. This is a job for a workshop.
Will P20DD clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.