P2BA9 fault code: what it means

P2BA9: NOx exceeded: AdBlue quality too low. The system sees poor NOx reduction, often from diluted or wrong fluid. Speed limits can follow.

Engine and gearbox (powertrain) · Costly if missed

Usual causes, most likely first

1. wrong or watered-down AdBlue
2. old AdBlue
3. failed NOx sensor
4. SCR catalyst

P2BA9 by make

What the repair usually costs

• AdBlue / SCR fault diagnosis (scan, NOx and doser tests)NZ$70–NZ$280 · A$80–A$300
• AdBlue tank assembly or SCR catalyst replacement (dealer part)NZ$3,150–NZ$8,600 · A$2,780–A$7,650

Not sure what P2BA9 means on your car? Ask Credov.

Before you clear it

Write the code down or photograph the scanner first. A code that comes straight back after clearing points to a fault that is still there. A car whose codes were cleared just before you arrived may be hiding one: the scanner's readiness monitors show "not ready" for a while after codes are cleared.

Researched by Credov from manufacturer and workshop sources. A fault code points to where a fault may be; a workshop confirms it with a diagnosis. Browse all fault codes.