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DTC code page

P0105: Manifold Absolute Pressure/Barometric Pressure Circuit Malfunction

Quick answer: The ECU sees a basic electrical or rationality problem in the MAP/barometric pressure circuit.

Drivers also search this fault as MAP sensor circuit malfunction, manifold pressure sensor fault, barometric pressure circuit fault.

Severity: medium Family: powertrain Related paths: 11
Meaning

What P0105 usually means

P0105 means the control module is no longer confident that the manifold absolute pressure signal is behaving like a believable load input. On many vehicles, the MAP sensor is also used to infer barometric pressure at key-on, so the fault can come from the sensor itself, its wiring, a blocked vacuum path, or a pressure reading that no longer matches real engine conditions.

Fast triage

Start here before chasing parts

  • Scan first: save freeze-frame and pending codes before clearing anything.
  • Confirm the complaint: compare the stored code with current drivability symptoms.
  • Use context: trims, live data, and related codes usually narrow the fault faster than guesswork.
  • Work simplest to hardest: leaks, connectors, maintenance items, and known patterns before expensive components.
Initial checks

What to check first

  • Look at MAP kPa on a key-on engine-off reading and compare it with local barometric pressure or a known-good vehicle if possible.
  • Inspect the connector, harness routing, and any vacuum nipple or hose at the sensor before replacing parts.
  • Check whether related throttle, lean, or correlation codes are stored because they often explain why the MAP reading looks wrong.
Driving risk

Can you keep driving?

A vehicle with P0105 may still run, but load calculation can become inaccurate. If it hesitates badly, starts hard, or drops into limp behavior, keep driving to a minimum until it is diagnosed.

Moderate urgency: This code often allows short-term driving, but the right fix usually comes faster when you diagnose it early instead of waiting for more codes.
Likely causes

Common causes behind this code

  • Failed MAP sensor or biased internal pressure element
  • Open, shorted, or high-resistance MAP sensor wiring
  • Lost 5-volt reference or weak ground on the sensor circuit
  • Blocked, split, or disconnected vacuum supply on systems that use a remote-mounted MAP sensor
  • Rare PCM input fault after sensor and circuit checks pass

Cause phrases often tied to this code: bad MAP sensor, 5-volt reference problem, signal wiring fault, vacuum hose issue, restricted intake.

Diagnostic order

Suggested workflow

  1. Compare key-on engine-off MAP data to expected barometric pressure for your altitude.
  2. Inspect the sensor connector, 5-volt reference, ground, and signal wire for opens, shorts, or poor terminal fit.
  3. If the design uses a vacuum hose, make sure it is not split, oil-soaked, or plugged with debris.
  4. Watch MAP response during snap throttle and decel to confirm the signal changes smoothly rather than freezing or dropping out.
  5. If the circuit tests good, verify the sensor is reading plausibly against engine load before replacing it.
Avoid guesswork

Common mistakes

  • Replacing the MAP sensor without checking for a lost reference voltage or weak ground.
  • Ignoring a damaged vacuum hose or clogged port on engines that do not mount the sensor directly on the manifold.
  • Judging the sensor only at idle instead of comparing key-on barometric reading and dynamic response.
Repair path

Practical fix guidance

  • Repair wiring, connector, or vacuum-feed problems first because they can mimic a failed sensor exactly.
  • If the MAP sensor is truly biased or dead, use a quality replacement and verify the reading is stable at key-on, idle, and light load.
  • After the repair, confirm related fuel-trim or reduced-power complaints do not return.
Vehicle context

Affected brands in this MVP

Brand hubs help broaden internal linking now and can evolve into make-specific diagnostic notes later.

Aliases and common searches

English phrases tied to P0105

Useful when the driver knows the wording but not the exact DTC yet.

  • MAP sensor circuit malfunction
  • manifold pressure sensor fault
  • barometric pressure circuit fault
Related search intent

Queries this page can answer naturally

  • P0105 code meaning
  • what does P0105 mean
  • MAP sensor circuit malfunction symptoms
  • barometric pressure sensor code
FAQ

Quick questions about P0105

Is P0105 the same thing as a bad MAP sensor?

Not automatically. The code covers the whole MAP/barometric circuit, including reference voltage, ground, connector fit, and vacuum feed issues.

Can altitude affect P0105 diagnosis?

Yes. MAP and barometric readings must be interpreted against local altitude, especially during key-on engine-off checks.

Will P0105 cause rough idle?

It can. A bad load signal can skew fueling and spark calculations enough to create rough idle or hesitation.