P1212 — Chevrolet — Mass Air Flow Circuit Intermittent Low

P1212 (Chevrolet): Mass Air Flow Circuit Intermittent Low — what it means, the affected system and what to check before replacing parts.

Meaning, symptoms, causes and checks

Mass Air Flow Circuit Intermittent Low. Source catalogue definition; confirm applicability using vehicle service information.

Affected system: Powertrain

Symptoms

  • Check Engine light illumination
  • Engine stalling or hesitation
  • Poor engine performance
  • Reduced fuel economy
  • Rough engine idle

Possible causes

  • Contaminated or faulty Mass Air Flow (MAF) sensor
  • Damaged or corroded MAF sensor wiring harness
  • Poor electrical connection at the MAF connector
  • Vacuum leaks in the intake system
  • Faulty Engine Control Module (ECM)

What to check

  • Inspect the MAF sensor connector for corrosion or bent pins
  • Test the MAF sensor wiring harness for continuity and shorts
  • Clean the MAF sensor element using an approved cleaner
  • Perform a smoke test to identify intake system vacuum leaks
  • Monitor MAF sensor data values with a scan tool during road test