I got these two messages when I started the car: “Warning: limited performance of the engine” and “Engine control system failure.” The car was shaking oddly and idled very rough. I tried restarting it, and the “loss of power” warning disappeared, and the shaking went away, but the other one remained. The car drove somewhat normally, and I drove it about 10 miles. Later, when I tried to drive it to the workshop, the same warnings came back, and the shaking, and the car wouldn’t rev past around 1,500 RPM. It was so weak it couldn’t make it up the garage ramp. Eventually, it barely moved at all - I had to push it around the garage to park it. It’s now been towed to the workshop. Has anyone experienced something similar or have any idea what could be causing it? FF 2012, ~45,500 miles. New PTU installed about 1 year / 3,000 miles ago. New DCT about 4 years / 15-20 000 miles ago. New oil pump and alternator within the past few thousand miles. It’s kind of like a difficult but wonderful girlfriend — you can’t live with it, but you can’t live without it either. Love it.
The car was clearly in limp mode which could be caused by any number of things. The rough idle suggests that something is wrong with a cylinder or cylinder bank. ECUs or injectors or spark plugs could be to blame. A readout from the OBD port will tell your mechanic what the problem is. That’s why I always travel on long trips with an Autel OBD dongle (available for less than €100) as it gives an immediate indication of how serious a problem might or might not be.
Here you go. Autel MaxiAP AP200 https://www.auteltools.eu/wholesale/autel-maxiap-ap200-obd2-scanner.html?gad_source=1&gad_campaignid=20899792720&gbraid=0AAAAAqrju20nZ9iJnUc0HSoelouV0OBML
Make sure your battery is fully charged. I got similar error messages and they all went away once the battery was fully charged.