P0106 Generic (SAE)

Manifold Absolute Pressure / Barometric Pressure Circuit Range/Performance

Updated 2026-10-02 · Fuel & air metering

Severity

Medium

Typical repair cost

25 – 400 EUR

System

Powertrain

What it means

The manifold absolute pressure (MAP) sensor reports intake vacuum or boost to the ECU, which cross-checks it against throttle position, rpm and (where fitted) the MAF reading. P0106 sets when the MAP signal is electrically valid but implausible, for instance showing near-atmospheric pressure at idle when strong vacuum is expected, or failing to match barometric pressure at key-on. The code means the sensor's reading does not agree with the rest of the engine's data, not that the circuit is open or shorted.

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Symptoms

Check engine light, often with a rough or hunting idle
Hesitation, surging or flat spots during acceleration
Black smoke or a strong fuel smell when the ECU over-fuels
Hard starting and occasional stalling after a cold start
Reduced boost or limp mode on turbocharged engines

Common causes

Cracked, disconnected or kinked vacuum hose to a remote-mounted MAP sensor
Intake manifold vacuum leak (gasket, PCV hose, brake booster hose) producing real but unexpected low vacuum
MAP sensor with a drifted output or carbon/oil contamination of its port
Blocked or restricted exhaust (clogged catalytic converter) raising manifold pressure
Poor engine mechanical condition (low compression, incorrect valve timing) lowering idle vacuum
Intermittent wiring fault or poor 5 V reference / ground causing a skewed but in-range signal

How to diagnose

Key on, engine off: compare the MAP reading with the scan tool's barometric value or local weather pressure; it should read about 95–102 kPa at sea level and the two should agree within 2–3 kPa
Start the engine and watch MAP at warm idle: a healthy naturally aspirated engine shows roughly 25–40 kPa (about 500–600 mmHg of vacuum); values of 60 kPa or higher at idle indicate a vacuum leak, restricted exhaust or sensor drift
Inspect the vacuum hose to the sensor and all manifold hoses; spray a small amount of brake cleaner or use a smoke machine around gaskets and connections to find leaks
Backprobe the sensor: confirm a 5.0 V reference and ground under 0.1 V, then compare signal voltage to a vacuum pump test (typical analogue MAP ≈ 4.5 V at 0 vacuum falling to ≈ 1.0–1.5 V at 500 mmHg)
Perform a snap throttle test on the scan tool graph: MAP should jump to near barometric instantly and drop back within a second; a sluggish response points to a clogged sensor port or hose
If the sensor tracks the vacuum pump correctly but idle vacuum is genuinely low, test exhaust back-pressure (should be under ~10 kPa at 2,500 rpm) and check compression and cam timing

Frequently asked questions

Is P0106 the sensor or a vacuum leak?

In practice a vacuum leak or cracked hose is more common than a failed sensor. Verify the sensor against barometric pressure at key-on and with a hand vacuum pump before replacing it.

Can a clogged catalytic converter cause P0106?

Yes. Exhaust restriction raises manifold pressure at idle and under load, which the ECU sees as an implausible MAP reading. A back-pressure test confirms it.

Does P0106 affect turbo engines differently?

On turbo engines the MAP sensor also measures boost, so a drifted sensor can cause over- or under-boost and trigger limp mode. Check charge pipes and intercooler hoses for leaks.