P2059 code meaning
Reductant Injection Air Pump Control Circuit/Open
Powertrain system Generic code P20xx codes Check engine light
What P2059 means
The air that atomizes DEF in an air-assisted system comes either from a small dedicated compressor or from an existing compressed-air system through a supply valve. P2059 concerns the driver circuit of that pump or valve, above all an open circuit: the output is switched on but no current flows. Deutz uses the code on its EMR L1 controller for the air pump or air supply valve (SPN 5796) with several failure types: -00 open circuit, -19 critically high output current, -31 load shorted and -2A unspecified electrical fault, while P2060 and P2061 cover high-side shorts to ground and battery. A blown fuse, a broken coil, an unplugged valve or corroded pins are typical. Without atomizing air the controller cannot dose DEF and NOx rises.
P2059 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 P2059
- Emission warning lamp on
- No DEF dosing, NOx rises
- Power derate on trucks and machines
Common causes of P2059
- Most likelyOpen coil in the air valve or pump motor
- PossibleConnector unplugged or corroded, wire broken
- PossibleFuse or relay in the supply path failed
- Less likelyShorted valve coil causing overcurrent shutdown
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Reductant air pumpReductant air pump relay
What each part of P2059 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. |
| 59 | The exact fault in that area. |
What to do next
- Note P2059 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 P2059
What does P2059 mean?
P2059 means "Reductant Injection Air Pump Control Circuit/Open". The air that atomizes DEF in an air-assisted system comes either from a small dedicated compressor or from an existing compressed-air system through a supply valve. It is a generic code, so it means the same on every make.
Is it safe to drive with P2059?
Drive gently and only to a workshop. With P2059 the car can go into limp mode (reduced power) to protect itself.
Will P2059 fail an emissions test?
Yes, it can. P2059 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 P2059 to fix?
Difficulty: medium. A typical repair takes 0.5 to 2.5 hours of work. This is a job for a workshop.
Will P2059 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.