P2BAD fault code: what it means

P2BAD: NOx emissions too high, root cause unknown. Usually a follow-on code to an AdBlue or EGR fault; diagnose the other codes first.

Engine and gearbox (powertrain) · Costly if missed

Usual causes, most likely first

AdBlue (SCR) system fault
poor quality AdBlue
faulty NOx sensor
EGR fault

P2BAD by make

Ford

NOx exceeded, cause not identified. The AdBlue/SCR system isn't cleaning the exhaust enough. Speed limits or no-restart can follow.

Usual causes: AdBlue dosing problem; failed NOx sensor; SCR catalyst failing; EGR fault

LDV

LDV diesel: nOx exceeded, cause unknown.

Usual causes: AdBlue dosing; NOx sensor; SCR catalyst; EGR

What the repair usually costs

EGR valve replacement or cleanNZ$350–NZ$1,710 · A$330–A$1,630
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 P2BAD 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.