Powertrain, generic (extended)

P230A Cylinder 1 Air-Fuel Ratio Imbalance - Adjustment At Limit During Balance

Check engine lightOn

EmissionsRelevant

Drive cycleRequired

Limp modeNo

P230A belongs to a second series of cylinder imbalance codes. P219C reports that cylinder 1 runs a mixture unlike the others; P230A goes a step further and says the balancing function has already moved the fuel correction for cylinder 1 to its end stop without evening it out. Such individual trims exist where the control unit can tell cylinders apart, for example on VW's 2014 2.5 litre five-cylinder, which leans out one cylinder at a time and read the resulting roughness. No maker documents P230A publicly; Mercedes describes the same idea on its M260/M264 four-cylinders under its own code P1CEF85 and traced it to leaking valve seats. Cylinder 1 exists on every engine, so any layout can set the code. CARB requires an imbalance monitor on all 2014 and later petrol cars.

Likely causes

Injector of cylinder 1 delivering too much or too little (deposits, wear)

Air leak at the intake port or injector seal of cylinder 1

Valve of cylinder 1 not sealing (worn seat or guide), low compression

Poor contact at the connector of injector 1

Symptoms

Check engine light on
Rough idle, possibly misfire on cylinder 1
Higher fuel consumption or exhaust smell

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 injector cyl 1intake manifoldcylinder compression

Related codes

P219C P230B P0301 P0201 P219A

References: law.cornell.edu, static.nhtsa.gov, static.nhtsa.gov.