Powertrain, generic (extended)

P2BA7 NOx Exceedence - Empty Reagent Tank

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

P2BA7 records that NOx control has been lost because the DEF or AdBlue tank has run dry, so no reagent can be dosed. Regulation (EU) 2017/1151 Annex XVI requires a level warning no later than 2,400 km ahead of an empty tank and an inducement that keeps the vehicle from operating with an empty tank, typically by blocking the next engine start after a countdown. CARB 13 CCR 1968.2 (f)(2.2.3)(B) asks for an empty-reagent diagnosis but exempts makers whose inducement prevents running dry. Ford lists P2BA7 in its 2014 code interpretation table; no public document gives a threshold. The normal level code is P203F; P2BA7 is the consequence once the tank is empty. Refilling with enough fluid usually clears warning and limits.

Likely causes

DEF tank simply not refilled despite level warnings
Level sensor reading empty although fluid is present (fault, ice, deposits)
Leaking DEF tank or line emptying the system
Only a small amount refilled, below the quantity the system needs to recognise a refill

Symptoms

  • DEF empty message with restart countdown
  • Engine will not restart once countdown expires
  • MIL or emission warning on

Repair estimate

DifficultyEasyDIY possible
Parts and labour€10–300
Time0.1–2 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

reductant tankreductant level sensor

Related codes

P203FP2BA8P2BAFP241D

References: legislation.gov.uk, law.cornell.edu, performanceparts.ford.com.