P0106 on 2007-2013 Mini Cooper: MAP Sensor, Carbon Buildup, and Fixes

What's Unique About the 2007-2013 Mini Cooper

The 2007-2013 Mini Cooper (R56 generation) uses two different but related 1.6L turbo engines: the N14 (2007-2010) and the N18 (2011-2013). The N14 engine is particularly notorious for severe carbon buildup on the intake valves due to its direct injection design. This buildup can restrict airflow, leading to incorrect pressure readings and triggering a P0106 code. While the N18 has an improved PCV design to reduce this issue, it can still occur. Additionally, some vehicles may have overly sensitive software that can falsely trigger this code, for which Mini has issued technical service bulletins (TSBs) like SI M 12 02 11 with a software update as the fix.

Generation note: This range covers the second-generation Mini Cooper (R56/R57/R58/R59). The key difference is the engine: 2007-2010 models use the N14 engine, which is highly susceptible to carbon buildup. 2011-2013 models use the updated N18 engine with a revised PCV system to mitigate carbon issues, though they are not immune. The root causes of P0106 are similar, but carbon buildup is a much higher probability on the N14.

Symptoms You May Notice

• Check Engine Light is on
• Rough or fluctuating idle
• Hesitation or bogging during acceleration
• Reduced engine power and turbo boost, possibly limp mode
• Poor fuel economy
• Black smoke from the exhaust
• In some cases, the engine may be hard to start

Most Likely Causes

1. Faulty Manifold Absolute Pressure (MAP/TMAP) Sensor(s) 🔴 High Probability These turbocharged engines have two pressure sensors (one pre-throttle body on the charge pipe, one on the intake manifold) that can become contaminated with oil from the PCV system or simply fail electronically over time.
   How to confirm: Use a scan tool to monitor live data from both sensors. With Key On, Engine Off, they should read close to local barometric pressure. At idle, the intake manifold sensor should show a deep vacuum (low pressure). If a sensor's reading is stuck, doesn't change with RPM, or reads illogically compared to the other, it's likely faulty. Swapping the two sensors (if they are identical part numbers) can see if the problem follows the sensor.
   Typical fix: Replace the faulty sensor. It's often recommended to clean the sensors first with an appropriate electronics/sensor cleaner before replacing. Given their critical function and exposure to oil, many owners replace them proactively.
   Est. part cost: $40-$120 per sensor, depending on OEM or aftermarket brand.
2. Carbon Buildup on Intake Valves 🔴 High Probability The N14 engine (2007-2010) is a direct-injection design where fuel doesn't wash over the intake valves. Oil vapor from the less-effective PCV system bakes onto the hot valves, forming thick carbon deposits that restrict airflow and cause a pressure discrepancy that triggers P0106.
   How to confirm: The definitive way to confirm is to remove the intake manifold and visually inspect the intake ports and valves with a borescope or by sight. Severe buildup will be obvious and look like black, hardened sludge covering the valve stems and ports.
   Typical fix: The most effective fix is walnut shell blasting, a procedure where crushed walnut shells are used to safely blast the carbon off the valves. This is a labor-intensive job, with independent shops often charging between $375-$800.
   Est. part cost: $20-$50 for intake manifold gaskets, but the labor/service is the main cost.
3. Vacuum Leaks 🟡 Medium Probability Plastic and rubber components in the engine bay, like the valve cover (with its integrated PCV system), intake hoses, and various gaskets, can crack and degrade over time. A torn PCV diaphragm in the valve cover is a very common source of a large vacuum leak.
   How to confirm: Perform a smoke test. This involves feeding pressurized, low-pressure smoke into the intake system and watching for where it escapes. A visual inspection may also reveal cracked hoses or oil residue around the valve cover seam.
   Typical fix: Replace the cracked hose, failed gasket, or faulty valve cover. The valve cover is replaced as a complete unit.
   Est. part cost: $20-$400 depending on the leaking component, with the valve cover being the most expensive.
4. Dirty Throttle Body ⚪ Low Probability Similar to the MAP sensors, the throttle body can accumulate oil and carbon deposits, preventing the throttle plate from moving correctly or sealing properly. This can cause the ECM to see a mismatch between the expected and actual airflow.
   How to confirm: Remove the intake piping connected to the throttle body and inspect the throttle plate and bore for a ring of black grime.
   Typical fix: Clean the throttle body carefully with a dedicated throttle body cleaner and a soft cloth. Do not force the electronic throttle plate by hand; have a helper turn the ignition on (engine off) and press the gas pedal to open the plate for cleaning.
   Est. part cost: $10 for cleaner and a gasket.

Rare But Worth Checking

• Sensitive or Outdated ECM Software: Mini released TSB SI M 12 02 11 stating the monitoring strategy for the MAP sensor was too sensitive and could incorrectly set a P0106. The fix is a software update (reprogramming the DME), not a part replacement.
• Wiring or Connector Issues: Damage to the wiring harness or corrosion in the connectors for the MAP sensors can cause an erratic or lost signal. This should be checked with a multimeter for proper voltage and ground before replacing sensors.
• Failed PCV System / Valve Cover: The PCV diaphragm can tear, causing a massive internal vacuum leak. On N14/N18 engines, the PCV system is integrated into the valve cover, requiring replacement of the entire cover. A sign of this can be a strong suction when trying to remove the oil cap while the engine is running.

Diagnosis Steps

1. Read all fault codes stored in the ECM. Note any other codes that are present, such as misfire or lean codes.
2. Using a scan tool, check the live data for BOTH MAP sensors with the Key On, Engine Off. They should read nearly identical values, corresponding to atmospheric pressure.
3. Start the engine and observe the MAP sensor readings at idle. The intake manifold sensor should show a strong vacuum (low voltage/pressure). The charge pipe sensor should read near atmospheric.
4. Visually inspect all accessible vacuum lines, the intake air ducts (especially the plastic pipe to the turbo), and the area around the valve cover for obvious cracks, damage, or oil residue indicating a leak.
5. Perform a smoke test to definitively identify any hard-to-see vacuum leaks in the intake system, including the valve cover PCV system.
6. If no leaks are found, remove and inspect both MAP sensors. Clean them with a dedicated sensor cleaner. Also inspect and clean the throttle body.
7. If the code persists, and especially if you have an N14 engine or high mileage, inspect the intake valves for carbon buildup using a borescope.
8. Check for any available TSBs related to P0106 for your specific model year, as an ECM software update (TSB SI M 12 02 11) may be the required fix.
9. If all else fails, test the wiring and connectors for the MAP sensors for continuity and proper voltage before condemning the ECM.

Parts You'll Likely Need

• Intake Manifold MAP Sensor (Post-Throttle Body) (OEM #12140872648 (N14) / 13627599907 (N18)) — This sensor is located on the plastic intake manifold and directly measures engine vacuum/pressure. It is prone to oil contamination and electronic failure.
  Trusted brands: Bosch, Continental/VDO, Genuine Mini
  OEM price range: $80-$120
  Aftermarket price range: $40-$80
• Charge Pipe TMAP Sensor (Pre-Throttle Body) (OEM #13627535069 (N)

Related Codes That Often Appear With This One

• P0171 — If a vacuum leak is the cause of P0106, the engine will also draw in unmetered air, causing a lean condition and triggering a 'System Too Lean' code.
• P030x (e.g., P0300, P0301) — Severe carbon buildup or vacuum leaks can disrupt the air-fuel mixture enough to cause random or specific cylinder misfires, especially during cold starts or under load.
• 2F22, P0128 — These codes relate to coolant temperature plausibility and are often seen when the thermostat is failing, a separate but common issue on this platform that can cause general driveability complaints.

Technical Service Bulletins (TSBs) & Recalls

• SI M 12 02 11 - Engine Electronics Software Update for P0106: This Service Information bulletin from BMW/Mini addresses an overly sensitive diagnostic threshold for the MAP sensor. The fault is stored incorrectly due to software logic, not a hardware failure. The fix is to reprogram the DME (ECM) with updated software (ISTA/P 2.41.0 or higher). This corroborates the 'Sensitive ECM Software' cause.
• Extended Warranty for High-Pressure Fuel Pump (HPFP): Mini USA extended the warranty on the HPFP to 10 years or 120,000 miles for N14 and N18 engines due to a high rate of failure. While not directly for P0106, a failing HPFP can cause performance issues that might be investigated alongside a P0106 code.

Platform-Specific Known Issues

• Owner Experience: P0106 Caused by Carbon Buildup: A 2009 Mini Cooper S owner on North American Motoring with 85,000km experienced intermittent hesitation. After trying a chemical cleaner (Seafoam) with minimal long-term success, they opted for a dealer walnut blasting service for $475 CAD, which is considered a reasonable price. Another user, a vendor, noted they charge $375 for the same service and sometimes have to make 2-3 passes to clean heavily carboned valves.
• Owner Experience: Misdiagnosis and Multiple Part Replacements: On a Reddit thread, a 2013 R58 (N18 engine) owner with 67k miles experienced sputtering and limp mode under acceleration. While suspecting carbon buildup, other users advised that on the N18, it's more likely to be spark plugs or ignition coils first. This highlights a common misdiagnosis path where owners jump to carbon cleaning when simpler issues are the cause.
• Owner Experience: The Two MAP Sensors: A user on North American Motoring who had just completed an engine swap on a 2008 Cooper S got a P0108 code (a related MAP sensor code) and couldn't locate the sensor. Another user clarified that there are two: one on the intake manifold (rear side, near firewall) and another on the charge pipe going to the throttle body. This is a critical piece of information for diagnosing P0106, as either sensor can be the cause.

Mechanic-Grade Diagnostic Values

• MAP Sensor Signal Wire Voltage (Key On, Engine Off) — expected: ~5.0V. Failure: Voltage significantly lower than 5.0V suggests a wiring issue or a faulty sensor. A 0V reading indicates an open circuit or short to ground.
• MAP Sensor Signal Wire Voltage (Engine at Idle) — expected: ~1.0V to 1.5V. Failure: Voltage remaining high (near 5V) indicates the sensor is not reading vacuum. Voltage that is erratic or doesn't respond to throttle changes points to a faulty sensor or intermittent connection.
• MAP Sensor Wiring Harness Resistance — expected: < 0.5 Ohms. Failure: A reading higher than 0.5 Ohms indicates high resistance in the wire, which can alter the signal. An 'O.L.' or infinite reading indicates an open circuit (broken wire).

Hidden / Shadow Codes Worth Checking

• 0x28A0: Throttle valve opening angle - intake pipe absolute pressure, comparison: pressure too high. This is the BMW/Mini specific fault code that directly corresponds to the logic of the generic P0106 code. It indicates the DME detected a mismatch between the measured manifold pressure and the pressure it expected to see based on throttle angle and other inputs. (see via BMW/Mini specific diagnostic software like ISTA, or advanced professional scan tools that can read manufacturer-specific codes.)

Scan Tool Commands That Help

• ISTA or equivalent professional scanner: Reset DME Adaptations / Clear Adaptation Values — This should be performed after replacing a MAP sensor, fixing a vacuum leak, or performing a carbon cleaning. The DME learns fuel trims and sensor plausibility values over time; resetting them forces the system to relearn with the new, correct conditions, preventing the old faulty logic from re-triggering the code.
• ISTA or equivalent professional scanner: Valvetronic: Run-in (or Adaptation) — On N18 engines (2011-2013) only. If any work has been done on the cylinder head or Valvetronic system, this function must be run. It teaches the DME the mechanical end-stops of the variable valve lift mechanism. Failure to do this can cause incorrect engine breathing and implausible manifold pressure readings, triggering P0106.

Wiring & Ground Locations

• Engine Ground Strap — The main engine-to-chassis ground strap is located on the passenger side of the engine bay, connecting the upper engine mount to the vehicle's frame rail/body.. A corroded or loose ground strap can cause floating ground issues, leading to unstable or incorrect voltage readings from all engine sensors, including the MAP sensors. This can cause erratic signals that trigger a P0106 code even if the sensors themselves are good.

Real Owner Repair Stories

• Reddit user in /r/MINI (2010 Mini Cooper S R56 (N14 engine)) — Occasional misfire on multiple cylinders, rough idle.
  ❌ Tried (didn't work) Spark plugs and ignition coils had been recently replaced.
  ✅ What actually fixed it Performing a walnut shell blasting of the intake valves to remove heavy carbon buildup. During the repair, a cracked crankcase vent hose was also discovered and replaced. The car idled normally and the code did not return.
• North American Motoring forum user (2009 Mini Cooper S (N14 engine)) — Car turns over but will not start after performing a walnut blast.
  ❌ Tried (didn't work) Resetting battery., Checking spark plugs (they were not wet).
  ✅ What actually fixed it The user did not post a final fix, but other experienced users noted that it is very common for the engine to take five or six start attempts before it will idle properly after a walnut blasting service. This is due to residual cleaner and dislodged carbon being burned off. This is a critical expectation to set for DIYers.
• YouTube user @jonmac11 (Mini Cooper S R56 (N14 engine)) — Misfiring and running poorly. Visual inspection showed intake valves were 'absolutely horrendous' with carbon.
  ❌ Tried (didn't work) Contacting the seller under warranty, who was unhelpful.
  ✅ What actually fixed it A DIY walnut blast of the intake valves. The user reported the car drove '80-90% better' afterwards, but suspected other issues like a fuel filter or O2 sensor might still be present, indicating the P0106 was caused by carbon but other issues were also present.

"I Checked Everything" — The Actual Cause

• A torn PCV diaphragm inside the valve cover. This creates a significant vacuum leak that is internal to the crankcase. A smoke test may not identify this if the test is not performed with the oil cap sealed, as the smoke may simply fill the crankcase without showing an external leak point. A tell-tale sign is a loud whistling noise or strong suction when removing the oil cap with the engine running.
• A stretched timing chain. This is a common failure on N14 engines. The chain stretch causes a deviation in camshaft timing relative to the crankshaft. The DME sees an implausible manifold pressure reading because the valves are not opening and closing when they are supposed to. This will never be found with a smoke test and requires checking cam/crank correlation with a scan tool or physically inspecting the chain and tensioner.

When the Usual Fixes Don't Work

• While replacing the MAP sensor is a common fix, many owners have replaced one or both sensors only to have the P0106 code return. In these cases, the root cause was often found to be a less obvious issue that also affects manifold pressure, such as a torn PCV diaphragm in the valve cover, severe carbon buildup on the intake valves (especially N14), or a stretched timing chain throwing off valve timing.

OEM Part Supersession History

• N/A - Correction → 13627535069 — Correction of Pass 2 data. The N14 engine does not use PN 12140872648. It uses two identical TMAP sensors (PN 13627535069) for both the pre-throttle body and intake manifold locations.
  Heads up: Part number 12140872648 is for the Gen 1 (R50/R53) supercharged engine and is incompatible with the Gen 2 N14 turbocharged engine.
• 13627535069 → 13627535069 — This is the correct TMAP sensor for the N14 engine (both locations) and the pre-throttle body location on the N18 engine.
• 13627599907 → 13627599907 — This is the correct MAP sensor for the N18 engine's intake manifold location. It is a different sensor from the TMAP used in the charge pipe on the same engine.
  Heads up: This sensor is for the N18 only and is not interchangeable with the N14's sensors.

Model Year Variations Within This Range

• 2011-2013 (N18 Engine): The N18 engine features BMW's Valvetronic system, which controls engine breathing primarily by varying intake valve lift, not with the throttle plate (except on cold start). When the engine is warm, the throttle plate is mostly open and manifold pressure is near atmospheric, not in a deep vacuum like the N14. This fundamental difference in operation changes the diagnostic context for P0106, as 'normal' pressure readings are different than on an N14.

Diagnostic Flowchart

Other Known Issues on This Vehicle

Issues unrelated to this code that are worth knowing about as an owner of this generation:

• Timing Chain 'Death Rattle' and Failure 🔴 High — Very common, especially on N14 engines (2007-2010). Can occur as early as 50,000 miles. Caused by a faulty chain tensioner, leading to chain stretch and broken plastic guides that can clog the oil pump pickup. (Ref: Multiple tensioner revisions were released by BMW/Mini to address the issue.)
• High-Pressure Fuel Pump (HPFP) Failure 🔴 High — Extremely common on N14 and to a lesser extent N18 engines. Failure can occur as early as 40,000-50,000 miles. Symptoms include long cranks, rough cold starts, sputtering, and limp mode, often with code P2880. (Ref: Mini issued an extended warranty for the HPFP for 10 years or 120,000 miles.)
• Thermostat Housing Leak 🟠 Medium — Common across the R56 generation. The plastic housing can crack or the seal can fail, leading to significant coolant loss. Often requires replacement of the entire housing assembly.
• Valve Cover / PCV System Failure 🟠 Medium — The PCV diaphragm, which is integrated into the valve cover, is known to tear. This creates a large vacuum leak, causing rough idle, oil consumption, and sometimes a whistling noise. The entire valve cover must be replaced.
• Water Pump / Friction Wheel Failure 🟠 Medium — The water pump can leak, and the friction wheel that drives it can also fail, leading to overheating. Some older models experienced issues with the water pump. (Ref: There was a recall on some earlier models for an auxiliary water pump, but the main pump remains a common failure point.)

Used vs. New Parts: Buying Guide for This Vehicle

When a used part is the smart pick: Used parts are generally not recommended for the key components related to this code. However, simple, non-critical items like intake ducting or brackets could be sourced from a donor car if in good condition.

Donor-vehicle mileage cap: roughly under 60000 miles for the part to have meaningful remaining life.

What to inspect on the donor part:

• Avoid parts from cars with flood or fire damage.
• Prefer donor cars with rear-end damage, as the engine bay is more likely to be intact.
• If possible, check the donor car's oil. Milky oil indicates a bad head gasket and a potentially abused engine.
• Inspect plastic and rubber parts for brittleness and cracks before purchasing.

OEM-only on this vehicle (don't cheap out):

• MAP/TMAP Sensors: Due to their electronic sensitivity and critical role, it is highly recommended to use OEM (Bosch, Continental/VDO) or Genuine Mini sensors. Cheap aftermarket sensors are a common source of persistent, hard-to-diagnose issues.
• Valve Cover (Plastic): The integrated PCV system is precisely calibrated. Many cheap aftermarket plastic valve covers use inferior diaphragms that fail quickly or are improperly calibrated, causing immediate running problems. A Genuine Mini or OEM-supplier part is the safest bet if replacing with plastic.

Aftermarket brands forum-validated for this vehicle:

• Bosch (for sensors)
• Continental/VDO (for sensors)
• SneedSpeed, Bremmen, Mitzone (for upgraded aluminum valve covers, which solve the warping/cracking issue of the stock plastic N14 cover)

Brands owners have reported issues with on this vehicle:

• Unbranded, no-name electronic sensors from online marketplaces.
• The cheapest available plastic valve covers, as they are frequently reported on forums to have immediate PCV-related issues.

Real Owner Stories

Aggregated from forums and TSBs cited above. Mileages and costs reflect what owners reported in those sources.

Related OBD-II Codes

• P0108 — A related MAP sensor circuit code that can occur alongside or instead of P0106 when one of the two pressure sensors fails or is disconnected.
• P0300 — Random misfire codes often accompany P0106 when severe carbon buildup on intake valves restricts airflow.
• P0171 — A lean condition code that may trigger if a vacuum leak, such as a torn PCV diaphragm in the valve cover, is the root cause of the P0106.

Frequently Asked Questions