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

P027F Cold Start Fuel Injection Quantity A Higher Than Expected

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modeNo

P027F is the cold-start counterpart of P026D: during cold start the engine gets more fuel than commanded, for example from a leaking injector or an EGR valve or throttle in the wrong position that reduces fresh air. The check probably works as in warm running, from airflow and lambda against the commanded quantity. The code covers only phases with the cold-start emission strategy active (extra injections to heat the catalyst, raised idle): CARB requires faults of elements also monitored elsewhere to be reported separately during the cold-start strategy. No manufacturer using this code was found; the description follows CARB and the warm-running counterpart.

Likely causes

Injector leaking or worn
EGR valve or intake/exhaust throttle in the wrong position (less fresh air)
Lambda/NOx sensor or airflow sensor reading wrong
Software

Symptoms

  • Check engine light on
  • White or black smoke after a cold start
  • Rough running when cold

Repair estimate

DifficultyHardWorkshop job
Parts and labour€100–4,000
Time0.5–6 h

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

Parts involved

fuel injectorsegr valvenox sensor

Related codes

P027EP026DP026CP0263P0380

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