P0106 Code: MAP Sensor Performance (GM Guide)

P0106 is "Manifold Absolute Pressure / Barometric Pressure Circuit Range/Performance." The module has decided the MAP reading is implausible for the conditions. Often that is a cheap sensor. But on GM's V8 engines there is a combination you need to know about, because GM has published multiple bulletins linking P0106 — together with P0300 and P0506 — to a broken valve spring. That is a serious mechanical failure, and replacing the sensor and driving on is how it turns into a destroyed cylinder head.

What Does P0106 Mean?

The MAP sensor measures pressure inside the intake manifold. The module uses that to calculate engine load, which drives fuel delivery, spark timing and — on many vehicles — transmission shift behaviour.

P0106 is a range/performance code, not a circuit code. The signal is present and electrically plausible; it just does not match what the module expects for the current throttle position, engine speed and barometric conditions. The related codes P0107 and P0108 are the circuit-low and circuit-high faults.

That distinction is the whole page. A MAP reading can be wrong because the sensor is faulty — or because manifold pressure genuinely is behaving strangely. The second possibility is what makes this code worth taking seriously on a GM V8.

The Three-Code Combination That Matters

If you have P0106 on a GM V8, the first thing to check is what else is stored.

GM has issued a series of preliminary information bulletins tying P0300, P0106 and P0506 together to one cause: a possible broken valve spring.

PIP5752E states the condition plainly: a vehicle may have a concern of service engine light, misfire and engine noise, with possible DTCs P0300, P0106 and P0506. GM's stated cause: possible broken valve spring. Its coverage is broad:

Vehicle	Year	Engines
Chevrolet Silverado	2020	5.3L L82 / L84, 6.2L L87, 6.6L L8T
GMC Sierra	2020	5.3L L82 / L84, 6.2L L87, 6.6L L8T
Chevrolet Tahoe, Suburban	2021	5.3L L84, 6.2L L87
GMC Yukon	2021	5.3L L84, 6.2L L87
Cadillac Escalade	2021	6.2L L87
Chevrolet Camaro	2020–2021	6.2L LT1, LT4
Chevrolet Corvette	2020	6.2L LT2

The earlier PIP5423 covers the same idea on older trucks: a vehicle may have a concern of the SES lamp with P0106 and P0506, and the instruction is to remove the valve cover and inspect for a broken valve spring.

PIP5801A (April 2021) extends the code list considerably — P0300, P0106, P0506, P3189, P318A through P318F and P3190 — with the same stated cause. It also gives the procedure once a broken spring is found:

• Perform a cylinder leakage test on the affected cylinder.
• If no cylinder leakage is observed, follow GM's replacement guidelines.
• For 6.2L engines (RPO L87, LT1, LT4, LT2): if the vehicle has under 1,000 km, replace all valve springs. Above 1,000 km, replace just the broken one.

PIP5752E also directs technicians to contact GM Technical Assistance where a valve spring concern is suspected, which tells you how seriously GM treats it.

Why a broken spring produces a MAP code: the valve no longer seals properly, so exhaust gases push back into the intake — reversion pulses. Manifold pressure fluctuates erratically, the module sees readings that make no sense, and P0106 sets. The sensor is reporting accurately. It is the manifold that is behaving strangely.

The tell: a ticking or light clanking noise from the engine alongside these codes. If you have P0106 with a misfire code and a tick, do not put a MAP sensor in it.

The Collapsed Intake Runner Check

This is a small instruction with expensive consequences, and it comes straight from PIP5423.

GM's direction: remove the valve cover and inspect for a broken valve spring — and if a broken valve spring is found, inspect the intake manifold for a collapsed runner.

The reason follows from the reversion described above. Hot exhaust gas being forced back through an open valve into a plastic intake manifold can soften and collapse the runner. So a broken spring can leave you with two damaged components, and fitting a new spring into a manifold with a collapsed runner leaves the driveability complaint unresolved.

It costs nothing to look once you are already in there, and it is the kind of step that gets skipped when someone is focused on the spring itself.

Cold Weather and Intake Icing

A second GM-documented path, and one that explains a code that appears only in winter.

On the older GMT900 trucks, GM identified ice forming in the intake manifold in cold weather, causing the MAP sensor to read incorrectly. Preliminary information reported as PI1257 addressed this on 2007-era models, and the reported fix is notable: a redesigned intake manifold that relocates the sensor — not a new sensor.

On newer trucks the same theme recurs. Bulletin 20-NA-043 is reported to cover ice forming on the TMAP sensor on 2017–2020 Sierra and Silverado, producing P0106. A related pattern documented across GM's small turbo engines is condensation freezing inside the sensor itself in cold conditions.

The diagnostic pattern to look for: the code appears in genuinely cold weather, often on the first cold morning of the season, and the vehicle behaves normally once everything has warmed through. That is ice, not a failed sensor, and replacing the sensor will not stop it recurring next winter.

We could not open PI1257 or 20-NA-043 directly, so treat those two as corroborated. The valve spring bulletins above we have read.

The 1.4L Turbo PCV Path

On the small turbo engines — Cruze, Sonic, Trax and Encore with the 1.4L — P0106 has a different and very well-known cause: a ruptured PCV diaphragm in the camshaft cover, or a missing check valve in the intake manifold.

That produces a substantial internal vacuum leak, and it characteristically sets P0106 alongside P0171 and P1101. The repair is the camshaft cover assembly, and where the intake manifold non-return valve is confirmed missing, the manifold.

The free check is the one every owner of these engines should know: try to lift the oil filler cap at idle. Unusually strong suction points at the crankcase ventilation system. Our P0171 guide covers this in full, including GM's inspection order and the crankcase pressure specification for these engines.

Note that a standard smoke test may not reveal this leak, because it is internal to the crankcase ventilation system rather than a hole to atmosphere. A clean smoke test does not clear the PCV path.

The Free Key-On Test

Before anything else, there is a check that costs nothing and takes a minute.

With the ignition on and the engine off, the intake manifold is at atmospheric pressure. So the MAP sensor should read essentially the same as barometric pressure. On a scan tool, compare the MAP reading against the BARO reading in that state.

• They should be close. A significant discrepancy with the engine off points at the sensor or its circuit, because there is no manifold behaviour to explain it.
• Then start the engine. MAP should drop sharply as vacuum develops, and respond smoothly to throttle.
• Erratic, jumpy readings at idle — particularly with a tick — are what reversion from a broken valve spring looks like.

While you are there, check the 5-volt reference and ground at the sensor connector. A missing reference or poor ground produces implausible readings from a healthy sensor.

Symptoms of P0106

• Check engine light on
• Rough or unstable idle
• Idle dropping low or stalling at stops — the P0506 side of the combination
• Hesitation, sluggish acceleration, poor fuel economy
• A ticking or light clanking noise from the engine — the valve spring warning sign
• Misfiring
• Black smoke or a rich smell where the module is calculating load wrongly
• Harsh or erratic shifting, since load feeds the transmission's decisions
• A code that appears only in cold weather and clears when warm

On urgency: if the cause is a broken valve spring, continuing to drive risks a dropped valve — which destroys the piston and cylinder head. A broken spring can also reduce vacuum available to the brake booster. Treat P0106 with a misfire, a low idle code or an engine tick as something to diagnose now, not next month.

What Causes P0106 — and How Do You Confirm Each One?

Cause	How to confirm it	Source
Broken valve spring	P0300 and/or P0506 alongside, plus an engine tick. Remove the valve cover and inspect. Cylinder leakage test on the affected cylinder	PIP5752E, PIP5423, PIP5801A — verified
Collapsed intake manifold runner	Inspect the manifold whenever a broken spring is found	PIP5423 — verified
Faulty MAP sensor	Compare MAP against BARO with the key on and engine off. A discrepancy there implicates the sensor	The most common simple cause
Ice in the intake or on the sensor	Cold-weather-only pattern that clears when warm	PI1257, 20-NA-043 — corroborated
Ruptured PCV diaphragm in the camshaft cover	Strong suction at the oil filler cap at idle. Often with P0171 and P1101	1.4L turbo engines
Missing intake manifold check valve	Inspect; manifold removal may be required to confirm	1.4L turbo engines
Vacuum leak — hoses, gaskets, brake booster line	Smoke test the intake tract. Note this will not find an internal PCV leak	The classic cause across the lineup
Dirty throttle body	Inspect and clean. A dirty throttle body can produce a false MAP code	Cheap to rule out
Oil or contamination on the sensor	Remove and inspect the sensor port	Common where crankcase ventilation is failing
Damaged wiring or connector	Check the 5V reference and ground; wiggle-test while watching live data	Heat and vibration damage
Camshaft actuator solenoid causing rough idle	On the 4.2L inline-six, a rough idle from the actuator can produce erratic manifold pressure	Reported on TrailBlazer applications

How Is P0106 Diagnosed?

1. Record every stored code. P0300 or P0506 alongside on a GM V8 changes this from a sensor job into a valve spring investigation.
2. Listen to the engine. A ticking or clanking noise with these codes is the valve spring signature.
3. Compare MAP against BARO with the key on and engine off. Free, and it separates a lying sensor from a misbehaving manifold.
4. Watch MAP live as the engine starts and revs. Erratic fluctuation at idle supports reversion.
5. Establish whether it only happens in cold weather, which points at icing rather than hardware.
6. On a 1.4L turbo, check the oil filler cap suction at idle for the PCV path.
7. Inspect and clean the throttle body, and check the sensor port for oil.
8. Smoke test the intake tract for vacuum leaks — remembering it will not find an internal PCV leak.
9. Check the sensor's 5V reference, ground and connector.
10. If the valve spring picture fits, remove the valve cover and inspect — and if a broken spring is found, perform a cylinder leakage test and check the intake manifold for a collapsed runner.

Parts and Cost

Repair	What it involves	Cost picture
Clean the throttle body	Removal and cleaning	Minimal — and it resolves some false MAP codes
MAP sensor	Usually accessible on the intake manifold. Order by VIN; the sensor for these trucks is commonly listed as 12644228	Inexpensive part, short job
Vacuum hose or gasket	Where a smoke test finds the leak	Modest
Camshaft cover assembly (1.4L turbo)	Where the PCV diaphragm has ruptured	Moderate — the correct fix on those engines
Intake manifold, icing redesign	Where the documented cold-weather fix relocates the sensor	Higher; VIN-specific
Valve spring replacement	Valve cover removal, cylinder leakage test, spring replacement. On 6.2L engines under 1,000 km GM directs replacing all springs; above that, just the broken one	Significant labour
Intake manifold after a collapsed runner	Where reversion has damaged the plastic manifold	Added to the valve spring job
Cylinder head or engine repair	What a dropped valve costs after driving on a broken spring	The outcome this page exists to prevent

GM Documents Relevant to P0106

Document	Subject	Coverage
PIP5752E	Service engine light, misfire and engine noise with possible DTCs P0300, P0106, P0506. Cause: possible broken valve spring. Contact GM Technical Assistance where suspected	Silverado / Sierra 2020 (5.3L L82/L84, 6.2L L87, 6.6L L8T), Tahoe / Suburban / Yukon 2021, Escalade 2021, Camaro 2020–2021, Corvette 2020 — verified
PIP5801A	Same condition with an extended DTC list including P3189 and P318A–P318F. Cylinder leakage test required; on 6.2L engines under 1,000 km replace all valve springs, above that replace the broken one	6.2L L87, LT1, LT4, LT2 and related — verified
PIP5423	SES lamp with P0106 and P0506. Remove the valve cover and inspect for a broken valve spring; if found, inspect the intake manifold for a collapsed runner	Earlier GM V8 trucks — verified
PI1257	Ice building up in the intake manifold in cold weather causing incorrect MAP readings; redesigned intake relocating the sensor	2007-era GMT900 trucks — corroborated
20-NA-043	Ice forming on the TMAP sensor producing P0106	Sierra / Silverado 2017–2020 — corroborated
N212330660 / PIP5787A	Faulty MAP sensor producing P0106, sometimes with P0108	Corroborated, not opened

What Other P0106 Pages Get Wrong

• Treating it as a sensor code full stop. GM has published at least three bulletins tying P0106 to a broken valve spring. On a V8 with a misfire code, a low idle code or an engine tick, fitting a MAP sensor and driving away is how a repairable spring becomes a dropped valve.
• Missing the three-code signature. P0300 plus P0106 plus P0506 is GM's own stated combination. Any one of them alone means much less than the three together.
• Skipping the collapsed runner check. GM's instruction is explicit — if a broken spring is found, inspect the intake manifold for a collapsed runner. Reversion damages plastic manifolds.
• Ignoring the mileage rule. GM distinguishes between vehicles under and over 1,000 km on the 6.2L engines when deciding whether to replace all sixteen springs or just the broken one. That is a real difference in scope and cost.
• Replacing sensors for a winter-only code. Ice in the intake or on the sensor produces this code seasonally. On the older trucks the documented fix relocates the sensor via a redesigned manifold rather than replacing it.
• Trusting a clean smoke test on a 1.4L turbo. A ruptured PCV diaphragm leaks internally, not to atmosphere. The oil filler cap suction check finds what the smoke machine misses.
• Overlooking the throttle body. A dirty throttle body can produce a false MAP performance code, and cleaning it is far cheaper than the sensor.

We publish coverage and instructions only where we could read them in GM's own documentation — here, three valve spring bulletins — and we label the rest as corroborated.

Frequently Asked Questions

Is it safe to drive with P0106?

It depends entirely on the cause, which is unusual for a sensor code. If it is a faulty sensor or a small vacuum leak, short-term driving is tolerable. If it is a broken valve spring, continuing to drive risks a dropped valve destroying the piston and cylinder head, and reduced vacuum to the brake booster. P0106 with a misfire, low idle or an engine tick should be diagnosed before further driving.

How do I know if it's a valve spring rather than the sensor?

Look at the other codes and listen. GM's documented combination is P0300 and P0506 alongside P0106, usually with a ticking or light clanking noise from the engine. A definitive check means removing the valve cover and inspecting, and a cylinder leakage test on the affected cylinder if a broken spring is found.

Do I need to replace all the valve springs?

GM's guidance in PIP5801A distinguishes by mileage on the 6.2L engines: under 1,000 km, replace all valve springs; above 1,000 km, replace just the broken one. That is for vehicles where the cylinder leakage test shows no leakage. Your dealer should be working to that rule rather than a blanket policy.

Why does my code only appear in cold weather?

Because it is probably ice. GM documented intake manifold icing on older trucks and ice forming on the TMAP sensor on newer ones, both producing this code. The pattern is a code in genuinely cold conditions that behaves once things warm through — and on the older trucks the fix relocated the sensor rather than replacing it.

Can a dirty throttle body cause P0106?

Yes, and it is worth ruling out early because cleaning costs almost nothing. Restricted or disturbed airflow into the manifold changes the pressure the sensor sees, and that can look like a sensor performance fault.

My smoke test was clean but I still have the code. What now?

On a 1.4L turbo, check the crankcase ventilation system — a ruptured PCV diaphragm leaks internally and a smoke test will not find it. Try lifting the oil filler cap at idle and feel for unusual suction. On a V8, revisit the valve spring possibility, particularly if a misfire or low idle code is stored.

What should the MAP read with the engine off?

Close to barometric pressure, because the manifold is at atmosphere with the engine stopped. Comparing the MAP and BARO values on a scan tool with the key on and engine off is the quickest way to tell whether the sensor itself is reporting sensibly.

Why does my transmission shift badly with a MAP code?

Because the module calculates engine load from manifold pressure, and shift pressure and timing depend on that load figure. A wrong MAP reading produces wrong load, which shows up as harsh or erratic shifts even with nothing wrong in the transmission.

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