AutoDiag

P0108

Manifold Absolute Pressure/Barometric Pressure Sensor Circuit High

Moderate· Fix soonDIY friendlyPowertrainGeneric, all makes

What it means

The manifold absolute pressure (MAP) sensor signal voltage is above the normal range. The manifold absolute pressure (MAP) sensor measures vacuum (pressure) inside the intake manifold so the ECU can calculate engine load and fuel delivery. A high signal is usually caused by an open circuit (unplugged, broken wire), a missing ground or a short to voltage.

Is it safe to drive?

Usually drivable, but fuel delivery may be wrong. Avoid long trips until fixed to protect the catalytic converter.

Symptoms

  • Check engine light on
  • Rough idle
  • Hesitation and poor power
  • Poor fuel economy
  • Black smoke from the exhaust
  • Hard starting

Probable causes

Most likely first

  1. 1Open sensor ground wire
  2. 2Signal wire shorted to the 5V reference or to battery voltage
  3. 3Corroded connector terminals
  4. 4Failed sensor

How to diagnose it

Work through these in order before buying parts

  1. 1Record the code and its freeze frame data (speed, load, temperature when it set), then clear it and see if it comes back.
  2. 2Inspect the manifold absolute pressure (MAP) sensor connector and wiring (on the intake manifold or connected to it by a vacuum hose). Look for corrosion, bent or pushed-back pins, oil contamination and chafed insulation.
  3. 3Watch the manifold absolute pressure (MAP) sensor reading on live data. With key on and engine off it should read close to barometric pressure (about 100 kPa at sea level). At warm idle a healthy engine usually reads 25–40 kPa (high vacuum).
  4. 4With the key on and the sensor unplugged, check for about 5 volts on the reference wire and a good ground (under 0.1 V drop) on the ground wire. Back-probe the signal wire with the sensor connected and watch the voltage change smoothly.
  5. 5If the wiring checks out, test the sensor itself against the specification in a service manual.
  6. 6Check for technical service bulletins (TSBs) or software updates for your make and model; some codes have known factory fixes.

Common fixes

  • Repair the damaged wiring or connector
  • Replace the manifold absolute pressure (MAP) sensor
  • Clear the code and test drive to confirm the repair

This information is general guidance for all makes. Exact causes, specifications and procedures vary by vehicle, so confirm with your service manual or a qualified mechanic before replacing parts.