Powertrain, generic (extended)

P219C Cylinder 1 Air-Fuel Ratio Imbalance

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modeNo

P219C names cylinder 1 as the one whose mixture departs from the others. Not every system can do that: CARB lets the stored code point only as far as the monitoring method allows, so many engines just log P219A or P219B. Those that resolve single cylinders include Toyota (the 2014 Corolla 2ZR gained P219C to P219F) and VW, whose 2014 2.5 litre five-cylinder leans each cylinder in turn and judges the resulting roughness, flagging a ratio below 0.19 or above 1.50. Subaru reflashed 2019 to 2020 Crosstrek Hybrid ECMs because P219C to P219F set without a real fault. Where the fault is real, check the cylinder 1 injector, its intake port seal and valve tightness with a leak-down test, as Toyota prescribes for the 2015 Tacoma V6. Cylinder numbering differs between makers, so confirm which cylinder is number 1.

Likely causes

Cylinder 1 injector clogged, leaking or out of tolerance
Valve leakage on cylinder 1 (leak-down test)
Intake runner or injector seal leak at cylinder 1
False detection fixed by ECM reprogramming (e.g. Subaru Crosstrek Hybrid)

Symptoms

  • Check engine light on
  • Often no noticeable symptom
  • Possible P0301 or rough idle if cylinder 1 deviates strongly

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€0–1,500
Time0.5–6 h

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

Parts involved

fuel injectorintake manifold

Related codes

P219AP219DP0301P0201

References: static.nhtsa.gov, static.nhtsa.gov, static.nhtsa.gov, static.nhtsa.gov.