P0419AIR System Control B Circuit
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Needs a drive cycle to confirm a fix
- How the car detects it
- After a cold start the secondary air (AIR) pump blows fresh air behind the exhaust valves so that unburnt fuel burns off and the catalyst heats up faster; a shut-off valve opens the path and stops exhaust from flowing back. Control B is the drive circuit of a second pump or pump relay, found only on systems with two pumps or relays, for example large V engines with one pump per bank. It is checked like P0418 by comparing the driver's feedback with its commanded state. No manufacturer document available to us describes P0419 specifically; Pierburg's fault table lists it as relay B with the same remedies as relay A.
- What you may notice
- Check engine light on
- Second pump does not run
- Secondary air readiness not set (emission test)
- Driving normal
- Likely causes
- LikelyPump relay B faulty
- LikelyWire or connector to relay B faulty
- PossibleFuse or supply
- RarePump B blocked (consequential damage)
- RareEngine module
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Easy · Often possible to do yourself.Typical cost: €20 – €700
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.