P0106: Manifold Absolute Pressure - Barometric Pressure Circuit Range - Performance

What does P0106 actually mean?

The manifold pressure sensor circuit is electrically sound, but its reading does not track plausibly with throttle position, rpm and other load related signals. This points to a sensor giving an inaccurate but not obviously broken signal.

The code sits in the manifold pressure sensor circuit area and is reported by the comprehensive component monitor. It names the circuit or the condition where the computer saw a reading outside its expected range. It does not name a failed part, and several genuinely different faults set this same code, which is the whole reason the causes below are ordered rather than listed.

What people usually notice

• Hesitation under load
• Rough idle
• Poor fuel economy
• Inconsistent power delivery

Why does P0106 set?

The causes below are ordered by how often they turn out to be the answer, cheapest and most common first. That order matters more than the list itself: the expensive component named in the code text is very rarely the first thing to replace, and working down from the top is what stops a manifold pressure sensor circuit fault becoming an expensive guess.

Vacuum leak affecting the reading is the one to rule out before anything else. A leak elsewhere in the intake can pull the manifold pressure reading out of its expected range at idle.

The order worth checking on P0106

Start with freeze frame. Manifold pressure and throttle position at the fault show the specific point where the mismatch occurred. That snapshot is taken at the instant the code set, and it is the single most useful piece of evidence you have, which is also why clearing the code before reading it is such a costly habit.

This code is diagnosed by watching values change rather than by reading the number again, so the tool has to stream live data and hold freeze frame. Comparing live manifold pressure to throttle position and rpm during a test drive reveals how far the reading has drifted from plausible values.

The order worth working in

• 1. Vacuum leak affecting the reading: A leak elsewhere in the intake can pull the manifold pressure reading out of its expected range at idle.
• 2. Partially clogged or kinked vacuum hose to the sensor: Restricts the pressure signal reaching the sensor without fully blocking it.
• 3. Sensor drifting out of calibration: Common on higher mileage vehicles, especially in hot engine bay locations.
• 4. Corroded connector adding resistance to the signal circuit: Can skew the voltage enough to fail the plausibility check.
• 5. Carbon or oil contamination on the sensor port: Buildup inside the sensor passage can dampen or delay its response.

Is it safe to drive with P0106?

The vehicle can be driven, though fuel delivery and ignition timing calculations depend on this signal and may be slightly off.

This is a severity 2 of 4 code. It will not usually strand you, but it will fail an emissions test while it is present, and the underlying fault rarely gets cheaper by being left alone.

What does it cost to ignore P0106?

An inaccurate load signal causes ongoing small errors in fuel and timing calculations, which shows up as wasted fuel and a rougher running engine over time.

There is also the diagnostic cost of waiting. Freeze frame data, pending code history and the readiness monitor state all describe the fault as it was when it set, and all of it is lost the moment somebody clears the code to make the lamp go out.