Porsche Cayenne loss of power problems

Filed Aug 11, 2026 · Electrical, Engine · TX

Nearly 25% of the total time I have owned this Certified Pre-Owned vehicle (146 out of 564 days), it has been non-functional and in the shop — roughly 1 out of every 4 days of ownership. I am a [XXX} with a [XXX] child, and I purchased this vehicle as a Certified Pre-Owned (CPO) Porsche — expecting the manufacturer's rigorous inspection and warranty to ensure reliability and safety. Instead, the first breakdown occurred within just 1 month of purchase, and the vehicle has since failed six separate times over 18 months (Feb 2025–Aug 2026), totaling 60+ days out of service, despite extensive component replacement: [XXX] (≈1 month after CPO purchase) – Battery failure; car would not start; towed at 2–3 AM. [XXX] – No-start; fuel tank drained/refueled ("improper additive"). [XXX] – Low fuel pump replaced. [XXX] – High fuel pump, all 6 fuel injectors, DME system replaced. [XXX] – Recurring no-start; repurchase denied May 7, 2025; Porsche later claimed root cause found (mechanical part) and replaced it. Aug 1, 2026–ongoing – Check engine light returned; misfire on cylinder 4 and coolant leak into vacuum system found. Dealer replaced coolant pump/vacuum components, updated DME software — check engine light reappeared on the dealer's own test drive. Why This Is Especially Dangerous: A CPO vehicle should not fail this quickly or repeatedly. It raised serious concern that either the inspection was inadequate or a pre-existing defect was never disclosed. My child rides in this vehicle regularly. A sudden stall or power loss at highway speed, at an intersection, or during school pickup/drop-off could cause a serious collision, endangering my child's life and my own. As a [XXX] with no backup driver/vehicle, an unexpected breakdown have cost lost work time, unreimbursed Uber expenses, and childcare disruptions. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Filed Jun 22, 2026 · Electrical, Engine · NJ

The hybrid cooling system on my 2019 Porsche Cayenne E-Hybrid repeatedly displayed a red dashboard warning while the vehicle was in motion: "Hybrid coolant level too low / Park vehicle safely / Let vehicle cool down." This warning appeared on multiple occasions at speeds of approximately 22 mph, 38–40 mph, and 47 mph, as documented in timestamped photos and videos taken in November 2025. A separate warning in July 2025 read: "Engine cannot be started / Remove charger plug." The warnings indicate a potential thermal management or hybrid cooling system failure. A moving vehicle being instructed to park and cool down presents a safety risk to the driver and others, particularly if the condition causes sudden power loss or thermal event. The vehicle was serviced at an authorized Porsche dealer in 2025. Despite that service activity, the hybrid coolant warning recurred while driving in November 2025, suggesting the underlying condition was not fully resolved. The issue was reported to the manufacturer (PCNA), who acknowledged it under a case number and offered a service voucher. The selling dealer attributed the concerns to a manufacturer charging-cable campaign. Neither response addressed the recurring in-motion warning or confirmed the hybrid cooling system was repaired. Timestamped photo and video evidence is available showing the dashboard warnings and vehicle speed at time of occurrence. Complete repair orders have been requested but not yet provided. The component may be available for inspection upon request.

Filed Jun 4, 2026 · Acceleration, Driver assistance · CA

1. Driving Conditions & Baseline State I was operating my new 2026 Porsche Cayenne (current mileage approx. 717 miles) at highway speeds inside a tunnel near LAX. The vehicle was functioning normally under normal driving conditions until the incident occurred suddenly and without any prior warning signs. 2. Onset of Failure & Dashboard Alerts - While maintaining speed, the vehicle suffered an immediate, simultaneous electronic and mechanical malfunction. The dashboard abruptly displayed an Adaptive Cruise Control (ACC) error/failure warning, along with auto start/stop failure. Immediately following this alert, the vehicle experienced a severe, sudden loss of mechanical power and propulsion. 3. Vehicle Behavior & Safety Hazard Pressing the accelerator pedal failed to yield normal engine response or acceleration. The drop in power felt as though the vehicle entered an unprompted "limp mode" or suffered a critical powertrain/software communication failure, severely limiting my ability to maintain highway speeds. Because this occurred inside a highway tunnel, the sudden deceleration presented an immediate and extreme safety hazard, nearly causing a rear-end collision with the traffic behind me. I was forced to navigate the underpowered vehicle out of the active lanes of traffic under highly dangerous conditions. After pulling over to a safe area and cycling the ignition (turning the vehicle off and back on), the mechanical power partially/fully returned, suggesting a transient or software-driven electronic control unit (ECU) fault. The historical error codes should be stored in the vehicle's modules. 4. Post-Incident State The vehicle was presented to McKenna Porsche (Norwalk, CA) the following day for diagnosis of the power loss and ACC failure. Safety Implications & Requested Action This component failure constitutes a critical safety defect. A total or partial loss of propulsion at highway speeds poses an unreasonable risk of severe injury or crash.

Filed Dec 8, 2025 · Electrical, Engine · AL

I am reporting a series of safety-related defects involving the electrical, cooling, and fuel systems of my 2021 Porsche Cayenne E-Hybrid. The vehicle was initially brought to the authorized Porsche dealership due to an electrical system error, and the dealer kept the vehicle for an extended period. After approximately five months, the vehicle was returned to me without a clear explanation of the root cause or details of the repair. The very next day after receiving the vehicle, a coolant temperature warning appeared while driving, indicating abnormal engine overheating. This created an immediate safety hazard, as overheating can lead to sudden engine failure, loss of power, or a potential fire risk. I returned the vehicle to the dealership again for further repairs. Afterward, another serious issue occurred: because this is a hybrid vehicle, I went to refuel, but the fuel door would not open, and a fuel system error warning appeared again. This made the vehicle unsafe to operate, especially while already on the road. Due to these repeated failures, I was required to tow the vehicle multiple times. These problems — electrical malfunction, coolant overheating during driving, fuel system errors, and a non-functional fuel door — occurred repeatedly even after prolonged service by the dealership. The combination of electrical faults, overheating risk, hybrid system malfunction, and fuel system failure presents a significant safety concern. I will provide additional documentation to support this report. I request that the federal safety agency review this case to determine whether an investigation is warranted, as these issues may indicate a broader defect affecting this model.

Filed Nov 9, 2025 · Acceleration, Engine · CA

While driving my 2019 Porsche Cayenne S on the freeway, the check-engine light came on, followed by a message on the dashboard that read “Engine Control fault – Driving permitted – Visit workshop.” Moments later, the vehicle suddenly lost power and decelerated from about ~75 mph to around 55 mph, even though my foot was still on the accelerator. I am [XXX] pregnant and had our [XXX] child in the car at the time. The unexpected loss of speed in fast-moving traffic was frightening. I had to quickly change lanes to reach the slower lane and avoid being hit by other vehicles. After reaching safety, I drove the car to an authorized Porsche dealership, where technicians found an active water-pump leak with coolant entering the vacuum system, which may have caused turbocharger and engine-power failure. This is after I replaced the water pump last year at another porsche dealership. A photo taken during the incident shows the dashboard warning message as it appeared. This incident created a serious safety hazard, as the vehicle displayed “driving permitted” even though it was at risk of a sudden loss of propulsion at highway speeds. The car and the failed components are available for inspection. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Filed Jul 5, 2025 · Driver assistance, Fuel system · CA

As I was making a turn onto another avenue, and accelerating to blend into traffic flow, dashboard messages suddenly appeared 1)"Engine control error, driving still possible, see dealer." 2)"Active lane keeping not available, driving still possible, service required" 3)"Adaptive Cruise Control not available, driving still possible, service required". Adaptive cruise was not engaged at the time of the error. The car lost almost all power, despite saying "driving still possible"; cars behind me had to brake hard as my car would only go about 7-10mph tops with accelerator firmly depressed and engine began to run very roughly. I coasted to shoulder of road, took video of error messages, turned car off and restarted car which cleared messages and car regained normal operation. I was glad this happened in-town and not when merging on a highway. This is not the first time the car has issued sudden warning messages stating certain systems had failed only to be cleared by restarting the car. I have taken the car to the dealer before to have them research the issue but they say errors cannot be replicated. However, this was the first time Engine control message posted and was the first time the car lost power and put me in danger of not being able to control the car's speed in traffic. I have lost faith in the car's control systems. I can live with lack of cruise control or lane keeping, but I cannot tolerate sudden lack of power than can cause an accident. This is my 3rd Cayenne, and unfortunately on this model, the electronics are ruining an otherwise well designed vehicle.

Filed Jan 29, 2024 · Fuel system · CO

Engine light came on and vehicle decelerated while making a turn in traffic. Based on the owners manual and code test, it comes up as a DPF issue. We could have been seriously injured had the oncoming traffic been closer to us or had someone attempted to follow me on the turn. When the car lost power, I could not accelerate to complete my turn. The problem has been duplicated by my husband who has some mechanical expertise, but the next step would be to take it to a dealer. It is available for inspection, but it is not safe to drive. The check engine light and the glow plug lamp came on at the same time. It happened once before on the interstate coming across I-80 on the interstate. In the middle of nowhere with no cell phone service, we were able to pull over, shut off and restart the engine which cleared the code for the rest of the trip. Then it didn’t do this again for nearly two months.

Filed Feb 3, 2021 · Acceleration, Transmission · 12,000 miles · LA

Tl* the contact owns a 2014 porsche cayenne. The contact stated that while driving at various speeds, a rattling noise occurred before the vehicle loss power and stalled. During the failure, the check engine warning light had illuminated. The vehicle was taken to the local dealer porsche of new orleans located at 3700 n causeway blvd, metairie, la 70002 who replaced the transmission transfer gear. Approximately 20,000 miles later the failure recurred and the contact was informed that the transfer gear was faulty and needed to be replaced a second time. In addition, the speed sensors in all four wheels were faulty causing the vehicle to randomly slow down and not accelerate. The sensors were replaced and the failure was remedied. The manufacturer was notified of the failures but no assistance was offered. The failure mileage was 12,000.

Filed Dec 20, 2020 · Fuel system · 119,000 miles · CA

Engine has cutoff on 3 occurrences: (1) operating the vehicle on the freeway at 70 MPH and experienced immediate loss of power. I was able to manuever the vehicle to the shoulder while coasting without engine power. I was able to start the engine but it cutoff a few seconds after. The vehicle had to be towed to an independent porsche repair shop where the high pressure fuel pump was replaced. (2) the engine cutoff while operating on city street at 40 MPH. I was able to manuever the vehicle while coasting without power or power steering into a parking lot. The engine would start but cutoff a few seconds later on multiple attempts. The vehicle has to be towed to the same independent porsche repair shop where the high pressure fuel sensor was replaced. This occurrence was the first time operating the vehicle after returning home from the high pressure fuel pump replacement service. (3) operating the vehicle while stopped at an intersection at a red light. When attempting to accelerate the engine cutoff and I was stalled for about 1 minute blocking traffic. I was able to restart the engine after a few attempts and drive the vehicle the remaining 2 miles home without incident. All 3 occurences involved abrupt engine cutoff and loss of power steering. The porsche independent repair shop is unable to pinpoint the issue. The risk exposure to accident is high when engine cutoff occurs while the vehicle is in motion.

Filed Jun 19, 2020 · Engine · 90,000 miles · CA

I have a 2012 porsche cayenne s hybrid. It is suffering from the defect described in this recall campaign: 17v36800. The bolts that hold the camshaft in place have sheared off. Porsche is refusing any type of consideration because the VIN is not in the recall list, but it is in the year of the recall and suffers from the issue. I was driving the vehicle on the highway and the check engine light came on. The vehicle lost power and the engine started knocking. I was able to coast to the shoulder. I had to call my wife and have it towed. The dealer told me it would cost 14k+ to repair and they would need the vehicle for a month.