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P2229 – Barometric Pressure Sensor Circuit High (OBD2)

P2229 means "Barometric Pressure Sensor Circuit High". The voltage in the manifold absolute pressure (MAP) sensor circuit is above the permitted maximum. For most sensors this points to an open signal or ground wire – the signal "floats" up to the reference voltage – or to a short to voltage.

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P2229 quick summary

Fault codeP2229
MeaningBarometric Pressure Sensor Circuit High
SystemPowertrain (Engine & Transmission)
VehiclesGeneric OBD2
SeverityMedium
Can I drive?Usually yes, gently. The engine runs on substitute values, so power and economy suffer and turbo engines may go into limp mode. Have it checked soon.
Repair cost€25 – €250

How the MAP and barometric pressure sensors work

The MAP sensor measures the absolute pressure in the intake manifold, which tells the engine control unit how much load the engine is under and, on turbo engines, how much boost there is.

The manifold absolute pressure sensor is a small sensor on or near the intake manifold, often combined with an intake air temperature sensor. It has three wires: 5 V reference, ground and signal. On naturally aspirated engines the pressure is lowest at idle (strong vacuum) and rises towards atmospheric pressure at full throttle; on turbo engines it continues to rise above atmospheric pressure as boost builds.

Many engines also have a barometric pressure sensor – either separate, built into the engine control unit, or read from the MAP sensor with the engine off. The control unit uses atmospheric pressure to correct fuelling and boost at altitude. Codes such as P0068 and P0069 compare these readings with the throttle position or the MAF value; when they do not agree, the engine cannot be sure how much air it is getting.

Because the MAP signal is used to calculate injection quantity and ignition timing, a faulty reading causes poor running, high fuel consumption and – on turbo engines – incorrect boost control or limp mode.

Symptoms of P2229

  • Check Engine light on
  • Hesitation, poor acceleration or limp mode (turbo engines)
  • Rough idle or stalling
  • Higher fuel consumption, black smoke on diesels
  • Hard starting

Most common causes of P2229 (most likely first)

Mechanic's Pro Tip

On diesels and direct-injection petrol engines, a MAP sensor clogged with oily soot is far more common than an electrically failed one. Pull the sensor out and look at the tip before ordering a new one – a careful clean with electrical contact cleaner often fixes the problem.

  1. 1.Open circuit in the signal or ground wire

    Most likely

    A loose ground connection is a very common cause.

  2. 2.Signal wire shorted to the 5 V reference or battery voltage

  3. 3.Faulty manifold absolute pressure (MAP) sensor

  4. 4.Cracked or disconnected vacuum hose to the sensor

    On sensors connected by a hose, a split hose makes the reading wrong; on directly mounted sensors a damaged O-ring does the same.

  5. 5.Sensor port blocked with oil or soot

    Oil mist from the crankcase ventilation and EGR soot can clog the small sensor opening – very common on diesels.

  6. 6.Intake or boost leak

    A real leak changes the measured pressure and can set range/performance or correlation codes.

  7. 7.Wiring fault or missing 5 V reference

    The reference is often shared with other sensors; a short in one of them can affect the MAP signal too.

Step-by-step diagnostic guide

  1. 1

    Read codes and compare with related sensors

    Read all fault codes. Check for related throttle, MAF, boost or reference voltage codes, which point to the real cause.

  2. 2

    Check signal and ground

    With the ignition on and the manifold absolute pressure (MAP) sensor plugged in, back-probe the signal and ground wires. A signal stuck at reference or battery voltage points to an open ground/signal wire or a short to voltage.

    Multimeter: Ground wire to battery negative: below about 0.1 V. Signal stuck at about 5 V (or 12 V) = open or short to voltage.

  3. 3

    Check key-on, engine-off reading

    With the ignition on and the engine off, the MAP and barometric readings should both equal the current atmospheric pressure (about 1,000 mbar / 100 kPa at sea level, less at altitude). A large difference between them points to the sensor.

    Multimeter: Key on, engine off: MAP ≈ barometric pressure ≈ 950–1,030 mbar near sea level. Warm idle on a naturally aspirated engine: about 300–400 mbar absolute.

  4. 4

    Inspect hoses, O-rings and the sensor port

    Remove the sensor and check the O-ring and the opening for oil or soot. Check any vacuum hose for cracks and correct routing.

  5. 5

    Check reference, ground and signal

    Measure the 5 V reference and ground at the connector and watch the signal change smoothly when revving the engine or applying vacuum with a hand pump.

  6. 6

    Clean or replace and re-test

    Clean a sooted sensor port carefully, replace the sensor if its readings are wrong, clear codes and confirm normal values on a test drive.

Frequently asked questions

Can I keep driving with P2229?

Usually yes, gently. The engine runs on substitute values, so power and economy suffer and turbo engines may go into limp mode. Have it checked soon.

How much does it cost to fix P2229?

Typical repair costs are 25 € – 250 €, depending on the cause and the vehicle. The most common fixes are: open circuit in the signal or ground wire; signal wire shorted to the 5 V reference or battery voltage; faulty manifold absolute pressure (MAP) sensor. Always confirm the cause with the tests above before buying parts.

What is the difference between a MAP and a MAF sensor?

A MAF sensor measures the mass of air flowing into the engine, while a MAP sensor measures the pressure in the intake manifold. Some engines use both, some only one. Both values are used to calculate how much fuel to inject.

Can a vacuum leak cause a MAP sensor code?

Yes. A real vacuum or boost leak changes the pressure the sensor sees, so range/performance or correlation codes can appear even though the sensor itself is fine.

What is the difference between P2229 and similar codes?

P2229 belongs to a group of codes for the same component that differ in the type or location of the fault: P0108 – Manifold Absolute Pressure/Barometric Pressure Circuit High Input; P0109 – Manifold Absolute Pressure/Barometric Pressure Circuit Intermittent; P0129 – Barometric Pressure Too Low; P2227 – Barometric Pressure Sensor Range/Performance; P2228 – Barometric Pressure Sensor Circuit Low; P2230 – Barometric Pressure Sensor Circuit Intermittent. The tests on this page apply to the whole group; the type of fault tells you where to start.

Related fault codes

This guide is for information only. Working on vehicles can be dangerous — if you are unsure, have the car checked by a qualified mechanic. Values can differ between model years; always check the manufacturer's repair information.