P2059: Reductant Injection Air Pump Control Circuit/Open
What to do
The car will feel normal — the consequence is legal rather than mechanical, because a dosing system that cannot spray eventually restricts operation by design. Treat the countdown warnings seriously and have the circuit repaired promptly; it is ordinary wiring work far more often than a pump.
What this code means
The control circuit for the reductant system's air pump has failed open.
Some dosing systems spray with compressed air, and the air is not optional. Air-assisted injection atomises the urea solution into a mist fine enough to convert in the exhaust stream — and atomisation is the whole defence against the crystallisation that the corpus's reductant pages keep returning to. A dosing system that loses its air lays down droplets instead of mist, and droplets become the hard white deposits that block injectors and pipes.
So this small pump's circuit codes matter beyond their size: the module typically suspends dosing rather than dose badly, and suspended dosing starts the inducement clock the NOx family describes at P2047 — a countdown to restricted operation on a vehicle that drives perfectly today. The circuit half is ordinary electrical work: wiring, connector, relay, then the pump.
Likely causes
Start here
- Open circuit in control wiring · moderate
- Corroded or loose connector · easy
Less common
- Faulty reductant air pump · moderate
- Blown fuse or failed supply · easy
Symptoms
Components involved
Information, not instruction
CarGeek is a reference, not a service manual. Its pages are written from public sources and from what other people have found, never from a manufacturer's own service information, so they can be wrong or incomplete for your particular vehicle. Some of what they describe carries real risk: high voltage, fuel under pressure, stored energy, hot and moving parts.
Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.
Community experience
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