The last naturally aspirated base Carrera and arguably the most reliable modern 911. The 9A1 engine has no IMS bearing issues and is mechanically robust. Main concerns are PDK transmission on early cars (internal sensors fail, replacement runs €18,000-30,000 but specialist repairs available for much less), PADM engine mounts (common failure, €2,500-3,500 replacement but sensor fix available for €220-300), and high-level brake light wiring (intermittent fault from spoiler hinge fatigue). Water pump failures on some cars, but extended warranty available. Manual gearbox is significantly more reliable than PDK.
Distance sensor most common culprit, causes limp mode or no reverse gear · more· less
The PDK distance sensor is by far the most common issue behind major PDK faults in the 991 generation. Fault codes typically in the P1731-P1734 range indicate sensor problems. Dealerships often recommend full transmission replacement (€18,000-30,000), but independent specialists can repair the PDK for one-third that cost by replacing internal sensors (€3,000-8,000). Early 991.1 cars (2012-2013) are most affected. 7th gear whining or difficulty engaging indicates mechanical wear (shift fork/synchronizer), often from degraded fluid. Original maintenance interval was 120,000 km/12 years but has been halved to 60,000 km/6 years. First-generation PDK lacks gear oil cooler, leading to premature sensor failure from excessive heat. Manual transmission cars avoid this issue entirely.
PADM engine mount failure€220 - €3,500
Electronic mount sensor fails, not the mount itself - Sport/Sport Plus modes stop working · more· less
PADM (Porsche Active Drivetrain Mounts) are electronically controlled engine mounts designed to stiffen during launch and cornering. These commonly fail on early 991.1 models, with "PADM System Fault" message on instrument cluster and Sport/Sport Plus buttons no longer affecting car behavior. Porsche dealerships charge €1,400-2,300 per mount plus labor (total €2,500-3,500 for both). However, in most cases the expensive mount hasn't failed - a small internal sensor has failed. Aftermarket replacement sensors cost €220-300 and can be installed by specialists, providing a permanent fix. Some owners convert to standard non-electronic mounts using PIWIS coding at specialist shops. Known issue on 991.1; updated parts available.
Water pump failure€1,400 - €3,500
Known manufacturing fault on 2018 cars, extended warranty available from Porsche · more· less
Water pump leaks are a known problem particularly on 991.2 models manufactured around 2018, with failures occurring as early as 9,000 miles. Porsche has acknowledged the manufacturing fault and extended warranty coverage on water pump and valve block to 10 years from new. Symptoms include coolant warning light, coolant leaks from cold (stops when warm), or poor cabin heating. Dealership replacement costs €3,100-3,500 including pump, thermostat, gaskets, seals, and coolant. Independent specialist pricing €1,400-2,200. Many owners have received free repairs even without CPO coverage due to widespread nature of issue. When replacing, ensure valve and lines are also replaced as repeat failures common if only pump is done.
High-level brake light wiring fault€3 - €600
Wiring to spoiler-mounted brake light fails from repeated deployment/retraction · more· less
The 3rd brake light located in the deployable rear spoiler develops intermittent faults as wires become brittle near the hinge from constant flexing. Warning message appears at highway speeds, often disappearing at lower speeds as spoiler retracts and broken wire reconnects. DIY fix costs €3 for butt connectors to splice the broken wire. Porsche part number for improved wiring harness is 991 612 881 01 (costs €150-250), though some owners report this can break again. Best solution is routing more robust wiring around the hinge rather than through it. Check 2-pin plug connection under fan assembly panel as loose connection can also trigger warning. Very common issue but inexpensive to fix.
COV solenoid failures€200 - €800
Change-over valves stick mechanically, causing cooling system faults or PSE failure · more· less
Early 991.1 cars had all 8 COV (Change-Over Valve) solenoids replaced in Porsche service campaign WC43. These vacuum-operated solenoids control various systems including cooling and PSE (Porsche Sport Exhaust). Symptoms include "Cooling System Fault" display, sport exhaust butterflies not operating, or heating/cooling issues. Original part number 7PP906283B was problematic and replaced with 7PP906283C, then 7PP906283F. Cost per solenoid €100-150, labor depends on location (some easy, some require extensive disassembly). Owners outside warranty should verify campaign completed - some cars showing campaign done still had faulty original solenoids installed. Replacement solenoids still fail, sometimes within months. If buying, check campaign status with VIN.
Suspension strut mount wear€400 - €1,200
Rubber bushings dry and fail over time, causing knocking from front/rear suspension · more· less
Upper strut mounts contain rubber bushings that dry and decline over time, allowing the strut to move and hit the body when riding over bumps. Produces a low-frequency thump or knocking noise, commonly from rear on 991.1. Front mounts also affected but less frequent. Parts cost €125-150 each plus VAT, with labor approximately €160 per side. Also involves replacing angular contact bearings below top mount. Total job including alignment runs €400-800 for one axle, €800-1,200 for both front and rear. Common wear item on cars 7+ years old. Not safety critical but annoying. Alignment required after replacement. Independent specialists can do for less than dealership pricing.
Early engines consumed 1 quart per 1,000 miles, most replaced under warranty · more· less
A significant number of early 991.1 engines (2012-2013) suffered high oil consumption, typically 1 quart per 1,000 miles driven. Porsche officially considers up to 1.5L per 1,000 km "acceptable" though this is excessive. In severe cases, engines were replaced under warranty. Later 991.1 production largely resolved this issue. Most 991.1 cars now show little to no oil consumption. If buying, check service history for oil consumption notes and verify engine hasn't been replaced. Consistent consumption of 1 quart per 3,000-5,000 miles is normal. Large spikes in consumption can indicate AOS failure, turbocharger issues (991.2), or bore scoring. Monitor oil level regularly. If problem occurs outside warranty, engine replacement is extremely expensive (€15,000+).
Radiator fan relay failure€85 - €1,400
Fan runs constantly at high speed even in cold weather, relay costs €85-95 · more· less
A common failure on 991 is left or right side radiator fan running continually at high speed at startup or during short drives even when engine and ambient temperature are cold. Typically caused by failed relay. Relay replacement costs €85-95 including labor. Relays are electromagnetic switches that control the 12V fan circuit based on low-voltage signals from Engine Control Module. No replacement schedule - some last many years, others fail prematurely. If fan itself is faulty (less common), fan motor replacement costs €1,300-1,400 or fan assembly €350-370. Check wiring and connectors for moisture/corrosion if relay replacement doesn't fix issue. Easy diagnosis - fans are accessible from wheel wells after removing liner. Simple repair but annoying symptom. Independent shops can diagnose and replace relay quickly.
Reliable for a sports car, but PDK and electronics need watching
The 991.1 Carrera is one of the most reliable modern 911s. The naturally aspirated 9A1 engine is robust with no IMS bearing concerns. Manual transmission cars are significantly more reliable than PDK-equipped models. Most issues are electrical/electronic rather than mechanical failures. Early production cars (2012-2013) had more teething problems that were resolved by 2014-2015. A thorough pre-purchase inspection and verification of service campaigns is essential.
Pre-Purchase Inspection Checklist
General checks
Service history
Complete Porsche dealer or specialist records essential. Verify oil changes every 15,000 km or annually, PDK fluid every 60,000 km.
Tires
Check tread depth, age (date codes), and uneven wear. N-rated tires strongly recommended (245/35R20 front, 305/30R20 rear on 20" wheels).
Cold start
Must start engine completely cold. Listen for unusual sounds, check for warning lights.
Body condition
Inspect for stone chips on front bumper and wide rear fenders. Check wheel arch paint for chips.
Test drive
Minimum 30 minutes including varied speeds and temperatures to check PDK when fully warmed.
Specific for this vehicle
PDK transmission operation (if equipped)
Drive for 20+ minutes until gearbox reaches full operating temperature. Feel for smooth shifts, no hesitation, jerking, or clunking. Test reverse gear. Check for any warning lights or messages. 7th gear whining indicates wear. Manual transmission cars are more reliable.
Test Sport/Sport Plus buttons for PADM function
If car has Sport Chrono, press Sport and Sport Plus buttons. Car behavior should noticeably change. If buttons light but no change in dynamics, PADM mounts likely failed.
Deploy rear spoiler and check brake light
Push spoiler button to deploy. Have someone press brakes while you check if spoiler-mounted brake light illuminates. If not, wiring harness issue likely.
Check for suspension knocking over bumps
Listen carefully for knocking or thumping from front or rear suspension, especially rear. Indicates worn strut mounts.
Verify coolant level and check for leaks
Engine should be cold. Check coolant level - low level could indicate water pump issues. Look under car for any coolant drips.
Check service campaign completion status
Provide VIN to Porsche dealer to verify COV solenoid campaign WC43 completed. Also check for any other open campaigns or extended warranties.
Inspect radiator fans at startup
On cold start, both radiator fans should operate briefly then stop. If either runs continuously at high speed, relay has failed.
Monitor oil consumption if test drive allows
Check oil level before and after longer test drives. Ask seller about oil consumption history. Review service records for oil top-ups between services.
Front hood lock bracket (2014-2015)Verify completed
Water pump and valve block extended warranty (10 years)Check eligibility
Contact a Porsche dealer with the VIN to verify all recalls and service campaigns have been completed. The COV solenoid campaign (WC43) is particularly important for early 991.1 models. Porsche has extended warranty coverage on water pump and valve block to 10 years from new due to manufacturing issues.
Warranty Status
Factory warranty (4 years / 80,000 km)Expired on all 991.1
Porsche Approved CPO (2 years / unlimited km)If certified
Water pump extended warranty (10 years)Check with dealer
All 2012-2016 Carrera 991.1 models are outside their original factory warranty. Consider purchasing a Porsche Approved Certified Pre-Owned vehicle for 2-year unlimited mileage warranty coverage. Water pump and valve block have extended 10-year warranty from Porsche due to widespread failures. Independent extended warranty options available but check exclusions carefully - some don't cover common 991 issues like PDK sensors or PADM mounts.
This report is for informational purposes only and does not constitute professional advice. Estimates may be inaccurate. Always have a qualified specialist inspect the vehicle before purchase. We accept no liability for decisions made based on this information.