Error code

OBD2 P0109

OBD2P0109
Diagnostic Trouble Code· Standard OBD-II fault code read from the vehicle's onboard diagnostics.

What it means

Manifold Absolute Pressure/Barometric Pressure Circuit Intermittent.

Severity

moderateCan drive but may experience performance issues. Addressing the issue is recommended.

Summary

P0109 indicates an intermittent issue with the Manifold Absolute Pressure (MAP) sensor or Barometric Pressure (BARO) sensor circuit, which can affect engine performance and fuel efficiency.

Symptoms

  • Illuminated CHECK ENGINE light
  • Increased fuel consumption
  • Decreased engine power and performance
  • Hard starting
  • Hesitation upon acceleration
  • Unpredictable engine stalling
  • Rough idling

Common Causes

  • Poor connections in wiring or connectors
  • Defective MAP sensor
  • Defective BARO sensor (if fitted)
  • Open circuits
  • Shorted, burnt, or damaged wiring and connectors
  • Clogged air filter element
  • Pinched vacuum hoses

Diagnosis

  1. Check for clogged or dirty air filters, damaged vacuum hoses, and catalytic converter issues.
  2. Inspect all wiring and connectors for damage; repair as needed.
  3. Perform ground, continuity, and reference voltage checks on sensor wiring.
  4. Test the MAP/MAF sensor according to manufacturer specifications.
  5. If using a MAF sensor, clean its element carefully with approved solvent.

Fixes

  • Replace faulty MAP or BARO sensor

FAQ

What does 'intermittent' mean in this context?

'Intermittent' indicates that the fault occurs sporadically and unpredictably.

How can I prevent P0109 from recurring?

Regular maintenance, such as checking air filters and vacuum hoses, can help prevent this issue.

View source

Not affiliated with OBD2. Answer summarized from the manufacturer's manual linked above; consult that source for the authoritative procedure.

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