P1106 Code: MAP Sensor Circuit Intermittent High Voltage (GM Guide)

P1106 is a GM-specific code: Manifold Absolute Pressure (MAP) Sensor Circuit Intermittent High Voltage. The word doing the work is intermittent. The module did not see a MAP signal that was permanently wrong — it saw one that jumped high and then came back. That single word changes the entire diagnosis, because a signal that spikes and recovers points at a connection, not a component. Chasing this code by replacing the sensor is how people end up with a new MAP sensor and the same light.

What Does P1106 Mean?

The manifold absolute pressure sensor reports the pressure inside the intake manifold. At idle, with the throttle closed, the engine is pulling hard against a nearly shut plate and manifold pressure is low — that is engine vacuum. Open the throttle and pressure rises toward atmospheric.

The sensor converts that pressure into a voltage the module reads, and the module uses it to calculate engine load, which drives fuel delivery and ignition timing.

High voltage means the sensor is reporting high manifold pressure — that is, low vacuum. The module reads that as heavy load. If the engine is actually idling at the time, the two facts are incompatible, and the module knows it.

P1106 sets when that implausible high reading appears intermittently — a spike rather than a sustained condition.

Why "Intermittent" Changes Everything

This is the most useful idea on the page, and it narrows the search dramatically.

Think about what can produce a signal that goes wrong and then comes back:

Fault type	Behaviour	Fits P1106?
A loose, corroded or spread connector terminal	Contact comes and goes with vibration, heat and movement	Yes — the classic match
A chafed wire touching something intermittently	Shorts when the harness moves, recovers when it settles	Yes
A failed sensor	Usually reads wrong consistently	Possible, but less characteristic
A blocked or disconnected vacuum line	Usually a steady wrong reading	Less likely for an intermittent

A component that has failed generally stays failed. A connection that has degraded comes and goes. GM even gave this fault its own code number rather than lumping it in with the standard MAP codes — that distinction is a hint about where to look.

Which makes the wiggle test the right technique here. With the engine running and a scan tool watching the MAP reading live, gently move the sensor connector, then the harness along its run, then tap lightly around the area. A reading that jumps when you move something has just told you where the fault is — something a static resistance check would never reveal.

And because the fault is intermittent, record the freeze frame data before clearing anything. It captures engine speed, load and temperature at the moment the spike happened, which is often the only description you will get of conditions that are hard to reproduce on demand.

The 5-Volt Reference It Shares

A detail that explains a confusing pattern of codes.

The MAP sensor does not have its own private power supply. It runs on a 5-volt reference that the module generates — and on most vehicles that same reference feeds several other sensors, commonly including the throttle position sensor and others.

Two consequences follow:

• A problem on the shared reference produces codes from multiple sensors at once. If you have P1106 alongside throttle position codes or other sensor faults that seem unrelated, suspect what they have in common rather than assuming several sensors failed together.
• GM has dedicated codes for reference voltage faults in this range. Their presence alongside P1106 points firmly at the supply rather than the MAP sensor.

This is the same reasoning that runs through several codes on this site — when unrelated components misbehave simultaneously, look at what they share. Our P0135 guide applies it to heater fuses, and our U0100 guide applies it to grounds.

Ground matters too. The sensor's signal is measured against its ground reference, so a poor ground shifts the reading without anything being wrong with the sensor itself. Voltage drop testing under load finds that; a static check does not.

The Vacuum Side, Where Fitted

Worth knowing because it depends on your engine's design.

Some MAP sensors mount directly on the intake manifold, sensing pressure through a port. Others sit remotely and connect via a vacuum hose.

If yours uses a hose, that hose is part of the circuit in every practical sense:

• A cracked or split hose lets the sensor see something closer to atmospheric pressure than actual manifold vacuum — which reads as high pressure, and therefore high voltage.
• A hose that has become soft or is collapsing can produce readings that change with engine movement and load, which fits an intermittent pattern well.
• Oil or fuel residue in the hose or port can restrict it, delaying or dampening what the sensor sees.

Older rubber hardens, cracks at the ends, and splits where it bends. This is a cheap thing to inspect and a cheap thing to replace, and it belongs on the list before a sensor does.

Where the sensor is manifold-mounted, check the port itself for carbon or residue, and check the sensor's O-ring or gasket — a poor seal there is effectively a vacuum leak at the measuring point.

A Warning About GM P1xxx Codes

This applies to every code in this range and it is worth stating plainly.

GM reused P1xxx code numbers across different model years and platforms for entirely different faults. Published GM code lists carry an explicit caution to that effect, and the examples are not subtle — nearby numbers in this same range are documented as meaning either an air conditioning pressure sensor fault or an oxygen sensor fault, or either a brake booster vacuum sensor fault or an oxygen sensor switching fault, depending on the vehicle.

Two practical consequences:

• Confirm the definition against your specific year, model and engine rather than against a general list. A definition that is correct for one GM vehicle can be wrong for another.
• Be careful with cross-manufacturer results. P1xxx codes are manufacturer-specific by definition, and other makes use the same numbers for unrelated faults. Advice written for another brand's P1106 does not describe your engine.

The definition used on this page — MAP Sensor Circuit Intermittent High Voltage — is the one that appears consistently across GM code references. But if your scan tool displays something different for P1106 on your vehicle, trust the tool and the service information over any article.

The Related Codes

Code	What it adds
P1107	The mirror image — MAP sensor circuit intermittent low voltage. Same reasoning, opposite direction
P0106	The generic MAP performance code — the reading is implausible rather than intermittently spiking. See our P0106 guide
P0107 / P0108	Generic MAP circuit low and high — sustained rather than intermittent
P1108	BARO to MAP comparison too high — the module comparing the MAP reading against barometric pressure and rejecting it
Throttle position codes	If present alongside, suspect the shared 5-volt reference rather than two failed sensors
Fuel trim codes	A wrong load calculation drives wrong fuelling. See our P0171 guide

Having both P1106 and P1107 is informative rather than confusing — a signal spiking in both directions is far more consistent with a loose connection than with a sensor that has drifted one way.

A Note on Sourcing for This Code

We cite documents we have read and label the rest.

We could not verify a GM service bulletin naming P1106 on a specific GM platform. The definition is consistent across GM code references, and the diagnostic reasoning here — intermittent means connection, the shared reference, the wiggle test — is standard practice rather than a GM document we opened.

This is also an older GM code, appearing in the manufacturer-specific set used across GM's OBD-II vehicles from the late 1990s onward. On more recent vehicles you are more likely to see the generic P0106, P0107 and P0108 codes instead.

Because of the code-reuse issue described above, checking your own vehicle's service information matters more here than on a generic code. A dealer can confirm what P1106 means on your specific VIN, and that is free.

Symptoms of P1106

• Check engine light, sometimes appearing and clearing on its own
• Intermittent driveability problems that are hard to reproduce
• Hesitation or a stumble that comes and goes
• Rough or unstable idle at times
• Reduced fuel economy
• Black smoke or a rich smell in some cases, since a high load reading commands more fuel
• Poor performance under acceleration
• Often normal operation most of the time

On urgency: moderate, but do not ignore it. The intermittent nature is exactly what makes it worth addressing — an unpredictable load signal produces unpredictable fuelling, and a fault that comes and goes today can become permanent tomorrow. The vehicle is generally drivable, but a stumble at the wrong moment in traffic is not something to plan around.

Causes and How to Confirm Each

Cause	How to confirm it	Notes
Loose, corroded or spread connector terminal	Wiggle test with live data running. Inspect terminals individually rather than looking at the connector face	The most likely cause. Intermittent means connection
Chafed or damaged wiring	Trace the harness, paying attention to where it passes brackets, edges and hot components	Moves with vibration, which fits the intermittent pattern
Shared 5-volt reference fault	Suspect strongly if throttle position or other sensor codes are stored alongside	Several sensors misbehaving at once means look at what they share
Poor ground	Voltage drop testing under load, not a static check	Shifts the signal without the sensor being faulty
Cracked, split or collapsing vacuum hose (where fitted)	Inspect the hose along its length and at both ends. Replace cheap old rubber rather than debating it	Only applies to remote-mounted sensors
Blocked or fouled manifold port	Inspect the port for carbon, oil or residue	Applies to manifold-mounted sensors
Moisture in the connector	Separate and inspect for corrosion and water	Explains weather-related intermittents
Failed MAP sensor	Compare live MAP reading against expected values for the engine's operating state	After wiring and vacuum are cleared
Large vacuum leak affecting actual manifold pressure	Smoke test the intake	The sensor may be reading accurately
ECM fault	Last, after everything else is excluded	Rare

How Is P1106 Diagnosed?

1. Record all codes and freeze frame data before clearing anything. On an intermittent fault that snapshot may be the best evidence you get.
2. Note whether other sensor codes are stored — throttle position codes alongside point at the shared 5-volt reference.
3. Confirm the definition for your specific vehicle, given that GM reused numbers in this range.
4. Inspect the MAP connector for corrosion, moisture, and spread or backed-out terminals. Check terminal grip rather than appearance.
5. Inspect the vacuum hose where the sensor is remote-mounted, or the manifold port where it is not.
6. Watch live MAP data and compare it against expected values — high vacuum at idle, rising toward atmospheric with throttle.
7. Perform a wiggle test with live data running: move the connector, flex the harness, tap gently. A reading that jumps identifies the fault location.
8. Voltage drop test the ground and check the 5-volt reference at the connector.
9. Smoke test the intake if manifold pressure may genuinely be wrong.
10. Replace the sensor only once the circuit is proven, and verify over enough driving to be confident an intermittent has not simply gone quiet.

Parts and Cost

Repair	What it involves	Cost picture
Clean or repair a connector terminal	Where corrosion or a spread terminal is found	The cheapest outcome, and the most likely one
Vacuum hose	Where the sensor is remote-mounted and the hose is old or cracked	Minimal. Old rubber is worth replacing on sight
Wiring repair and reroute	Where chafing is found. Reroute clear of the contact point	Modest — and the reroute prevents the repeat
Ground repair	Where voltage drop testing finds a poor ground	Modest
MAP sensor	Generally an inexpensive, accessible part on most engines	Moderate. Match to VIN
Intake gasket or hose for a genuine leak	Where the manifold pressure really is wrong	Varies with access
Sensor replaced while a bad connector remains	What happens when the wiggle test is skipped	Part and labour spent, intermittent still present

Order against your VIN. MAP sensors vary by engine and calibration, and a physically similar sensor from another application is not necessarily correct.

What Other P1106 Pages Get Wrong

• Ignoring the word "intermittent." GM gave this fault a separate code from the standard MAP codes precisely because the signal comes and goes. That behaviour points at connections, not components — and it is the single biggest clue the code contains.
• Never mentioning the wiggle test. An intermittent circuit fault is found by making it happen while you watch live data, not by static resistance checks that pass every time.
• Missing the shared 5-volt reference. Several sensors run off one supply. Unrelated sensor codes appearing together point at the supply rather than at multiple failed sensors.
• Skipping the vacuum hose. Where the sensor is remote-mounted, a cracked hose produces exactly this reading, and old rubber is cheap to replace.
• Presenting one definition as universal. GM reused P1xxx numbers across model years for different faults, and other manufacturers use the same numbers for entirely unrelated problems. Confirm against your own vehicle.
• Clearing the code before recording freeze frame data. On an intermittent fault, that snapshot of engine conditions is often the most useful thing available.
• Declaring it fixed too early. An intermittent that has gone quiet for a day has not necessarily been repaired. Verify across enough driving to be confident.

Frequently Asked Questions

Do I need a new MAP sensor?

Probably not first. The word "intermittent" in this code's definition points at a connection rather than a component — a failed sensor usually reads wrong consistently, while a loose or corroded terminal comes and goes. Inspect the connector and do a wiggle test with live data before ordering a part.

What is a wiggle test?

With the engine running and a scan tool showing the live MAP reading, you gently move the sensor connector, flex the harness along its run, and tap lightly around the area. If the reading jumps when you move something, you have located the fault. It is the standard way to find an intermittent circuit problem, and static resistance checks will not do it.

I have throttle position codes too. Are they related?

Quite possibly. The MAP sensor shares a 5-volt reference with several other sensors, commonly including the throttle position sensor. A problem on that shared supply produces codes from multiple sensors at once, which is far more likely than several sensors failing simultaneously.

Can a vacuum hose cause this?

Yes, on engines where the MAP sensor is remote-mounted and connected by a hose. A cracked or split hose lets the sensor see something closer to atmospheric pressure than real manifold vacuum, which reads as high pressure and high voltage. Old rubber cracks at the ends and where it bends, and it is inexpensive to replace.

Can I drive with P1106?

Generally yes, and much of the time the vehicle behaves normally. The concern is the unpredictability — a wrong load signal produces wrong fuelling, and a hesitation or stumble arriving at an awkward moment in traffic is worth avoiding. Intermittent faults also tend to become permanent ones.

Why does the light come on and go off by itself?

Because the fault is intermittent by definition. The module sets the code when it sees the spike, and if the condition does not recur across subsequent drive cycles the light can extinguish while the code remains in history. That is why recording freeze frame data before clearing anything matters.

My scan tool shows a different definition for P1106. Which is right?

Trust your scan tool and your vehicle's service information. GM reused P1xxx numbers across model years and platforms for different faults, and published code lists carry an explicit warning about it. Other manufacturers also use these numbers for entirely unrelated problems.

What's the difference between P1106 and P0106?

P1106 is GM's manufacturer-specific code for an intermittently high MAP signal. P0106 is the generic MAP performance code, meaning the reading is implausible for the conditions rather than spiking and recovering. On newer GM vehicles you are more likely to encounter the generic codes.

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