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DTC codes / P01xx · Fuel and air metering / P0107

P0107MAP/Barometric Pressure Circuit Low Input

P0107 means the manifold absolute pressure (MAP) sensor or barometric pressure (BARO) sensor circuit is reporting a voltage lower than the powertrain control module (PCM) expects for the current operating conditions. The PCM compares the sensor signal to its calculated pressure model and flags the circuit as low when the voltage stays below the calibrated threshold for a set time.

SystemPowertrain
Code typeGeneric (all makes)
SeverityMedium
Fix difficultyIntermediate
AreaFuel and air metering

Symptoms you may notice

  • Illumination of the check engine light, often with no other noticeable symptoms
  • Rough idle, stalling, or surging because the PCM is using a default pressure value instead of the real sensor reading
  • Poor fuel economy or a rich-running condition from incorrect fuel delivery calculations
  • Hesitation or weak acceleration when the engine is under load
  • Hard starting or an engine that starts and immediately dies in severe cases
  • A failed emissions test due to incorrect air-fuel ratio control

Common causes, most likely first

  1. A short to ground or chafed wire in the MAP/BARO sensor signal circuit
  2. A faulty MAP or BARO sensor that internally shorts the signal line low
  3. Corroded, loose, or pushed-back pins in the sensor or PCM connector
  4. A clogged or restricted vacuum hose or port feeding the MAP sensor, causing an artificially low pressure reading
  5. A failed PCM driver or internal circuit fault, though this is rare
  6. Water intrusion into the sensor or connector causing a low-resistance path to ground

How to diagnose and fix it

  1. Connect a scan tool and read the MAP/BARO voltage and pressure values with the key on, engine off, then compare them to the expected barometric pressure for your altitude
  2. Inspect the sensor connector and the full length of the signal wire for chafing, corrosion, or a short to ground, repairing any damage found
  3. Check the vacuum hose and port between the intake manifold and MAP sensor for cracks, blockage, or disconnection, and clear or replace as needed
  4. Back-probe the sensor signal wire at the PCM and measure voltage with the key on; if it stays near zero volts while the sensor is unplugged, the short is in the harness
  5. Disconnect the sensor and check for reference voltage and ground at the connector; missing reference voltage points to a wiring or PCM issue rather than the sensor
  6. Replace the MAP or BARO sensor only after the circuit and vacuum supply have been verified good, then clear the code and confirm the voltage reads correctly
  7. Road-test the vehicle through several drive cycles to confirm the code does not return and that fuel trims and idle quality are normal

What the low MAP voltage really means

  • A MAP sensor reading low voltage does not automatically mean the sensor is bad; a shorted signal wire or a bad ground connection will produce the same code and replacing the sensor will not fix it.
  • On many vehicles the barometric pressure reading is taken from the MAP sensor at key-on before the engine starts, so a low BARO value can set P0107 even though the engine runs fine once started.
  • A restricted or disconnected vacuum hose to the MAP sensor can pull the signal low under certain conditions, and this is frequently overlooked because the sensor itself tests good on the bench.
  • Technicians sometimes misdiagnose P0107 as a fuel pump or ignition problem because the drivability symptoms overlap, so always verify the MAP voltage with a scan tool before chasing other systems.
  • Water or oil intrusion into the MAP sensor connector from a nearby leak or a missing splash shield can create a low-resistance path that mimics a failed sensor and returns after replacement if the source is not fixed.

Can I keep driving with P0107?

You can usually drive the vehicle to a repair shop, but avoid heavy acceleration, towing, or long trips because the PCM is running on default pressure values and fuel economy and emissions will suffer. If the engine stalls, idles roughly, or hesitates badly, stop driving and have it diagnosed promptly.

Tools that help

Tools we recommend are in the Auto Veteran shop on Amazon. As an Amazon Associate we earn from qualifying purchases.

Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.

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