Powertrain, generic (extended)

P219A Bank 1 Air-Fuel Ratio Imbalance

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modeNo

P219A means the ECM sees mixture differences between the cylinders of bank 1 that are large enough to raise emissions, even if the bank average is fine. CARB phased this monitor in from 25 % of 2011 to all 2014 model-year petrol vehicles (13 CCR 1968.2 (e)(6.2.1)(C)). GM measures how much the upstream sensor signal varies per firing event, normalises the result against a map of a healthy engine and flags a ratio above 1.05 (one 2016 engine, 1100 to 3500 rpm, Type A, one trip). Mitsubishi counts rich and lean peaks at 1750 to 3250 rpm and 40 to 70 % volumetric efficiency. On inline engines bank 1 is the whole engine. Toyota traced P219A on 2012 to 2014 Corolla 2ZR engines to compression escaping into the exhaust; from 2014 the Corolla adds the cylinder codes P219C to P219F.

Likely causes

One injector clogged, leaking or out of flow tolerance
Compression loss through an intake or exhaust valve
Air leak at one intake runner or gasket
ECM logic or sensor signal issue covered by software or wiring bulletins

Symptoms

  • Check engine light on
  • Often no noticeable symptom
  • Slight rough running or misfire codes when one cylinder is far off

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€0–2,000
Time1–6 h

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

Parts involved

fuel injectoroxygen sensorintake manifold

Related codes

P219BP219CP219DP219EP219FP0300P2195

References: law.cornell.edu, gsi.ext.gm.com, mitsubishitechinfo.com, static.nhtsa.gov.