Powertrain, generic · Fuel and air metering (injector circuit)

P02A3 Cylinder 3 - Fuel Trim at Min Limit

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modeNo

These codes belong to an individual-cylinder fuel correction: a diesel's cylinder balance control measures each cylinder's crankshaft acceleration and adjusts its injection quantity; on petrol engines a cylinder-selective mixture control does the same. CARB requires the system to report when such a correction has used up its range or one cylinder causes an imbalance. P02A3 means the correction for cylinder 3 is at its lower limit: the module keeps taking fuel away from this cylinder and still cannot even it out – a sign that it receives too much fuel, for example from a dripping injector. GM and Ford use other codes for this (P0263 ff, P219A ff); no manufacturer document describing this code with thresholds was found, so the description follows CARB and published patents.

Likely causes

Injector of cylinder 3 dripping or leaking
Injector with excessive flow (worn seat or needle)
Wrong injector correction code after replacement
Injector circuit short (extended activation)

Symptoms

  • Check engine light on
  • Rough idle, vibration
  • Higher consumption, smoke or fuel smell

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€150–900
Time1–4 h

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

Parts involved

fuel injector cylinder 3crankshaft position sensorengine control module

Related codes

P02A2P02A4P02A5P0172P0269P02D0

References: law.cornell.edu, patents.google.com, patents.google.com.