Powertrain, generic (extended)

P243A Particulate Filter Restriction - Ash Accumulation (Bank 2)

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

P243A is the bank 2 counterpart of P242F: the ash load in the second particulate filter has grown so large that the filter chokes the exhaust and must be cleaned or replaced. A bank 2 filter only exists where each cylinder bank of a V engine feeds its own filter strand. No manufacturer documents this exact code publicly. Bank 1 monitoring shows how such a check works: GM's 2018 diesels judge ash by a filtered flow resistance derived from differential pressure and exhaust flow (Type A), and Deutz raises a warning once a modelled ash load limit is passed. Since ash does not burn, extra regenerations will not help and only waste fuel. If only one strand shows high back pressure or regenerates more often, the problem is confined to that side.

Likely causes

Bank 2 filter full of ash after long service
Oil burning on bank 2 (valve stem seals, turbo seal) adding ash
Bank 2 pressure sensor or hose reporting too much restriction

Symptoms

  • MIL or filter service message
  • Higher fuel consumption from frequent regenerations
  • Reduced power at high load

Repair estimate

DifficultyHardWorkshop job
Parts and labour€300–3,000
Time1–4 h

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

Parts involved

dpf b2

Related codes

P242FP24A3P243FP2003

References: gsi.ext.gm.com, serdia.deutz.com, law.cornell.edu.