PADM Working Logic and Maintenance Methods

[poporacing01]

As long as your 911 or 718 was originally equipped with SC components, it will have this dynamic engine mount. However, its failure rate is very high, and the cost of replacing parts is extremely expensive. When you factor in labor costs, it’s no surprise that this can be a significant expense.

1. How does the PADM system work?

The engine mounts of ordinary civilian vehicles are generally made of rubber, with better ones filled with hydraulic oil. It is a relatively soft connection with cushioning. Its advantage is that it is comfortable and suitable for daily use. The disadvantage is that soft connections consume some power, just like punching a sponge, and under the influence of centrifugal force in curves, soft connections cannot hold the engine and transmission in place, causing their center of gravity to shift.

In contrast, racing machine feet are rigidly connected. You can imagine them as steel plates. Their advantage is that there is no power loss or shift in center of gravity, but their disadvantage is that you simply cannot tolerate the vibration and noise they generate.

The Porsche PADM system combines the advantages of soft and rigid connections. From an overall structural perspective, the dynamic engine mount consists of three parts: the outer shell, internal magnetic fluid, and sensors. Its operating principle is relatively simple: when the current passing through the coil changes, the surrounding magnetic field also changes. The magnetic fluid is affected by the magnetic field, becoming softer or harder.

The PADM system operates on a principle similar to electronic damping but incorporates an additional real-time feedback system. Conventional electromagnetic damping systems employ segmented regulation, whereas the PADM system features a real-time feedback mechanism, enabling it to respond extremely quickly. It also offers different operating modes. In standard mode, the system prioritizes comfort, with gradual adjustments and minimal regulation, resulting in very weak current flow. only a few tenths of an ampere, approaching zero. The damaged machine feet are naturally at zero, and the extremely weak current is imperceptible to the human body.

When Sport+ mode is activated and the vehicle is driven aggressively, the changes are significant. At this point, the instantaneous current reaches 6 amperes, which is a very high operating current. Whether the motor mount is stretched or compressed, the current inside increases, causing the mount to harden to resist deformation. Therefore, no abnormalities can be detected by the human body during idle operation, as the mount only operates intensively during aggressive driving, especially when Sport+ mode is activated.

2. How was the PADM system damaged?

The dynamic engine mount themselves are unlikely to be damaged; all damage comes from the sensors inside the square box.

Disassembly steps:
①Open the cover to see the sensor chip.


② Open the chip cover to see that the magnetic fluid has overflowed.

③Carefully search through the magnetic fluid to find the detached core. The original core is glued in place, and the detached core is the cause of the damage to the dynamic engine mount.

3. How to repair fault?

Replace all the old sensors with new ones, and the fault will disappear, restoring the system to normal operation. Based on the newly read data stream, the new sensors have the same sensitivity as the original ones, as well as the same range and frequency of change. It should be noted that Porsche does not offer replacement sensors as individual parts; only the entire dynamic mount can be replaced, making the cost prohibitive and posing a repair challenge for Porsche owners.

The new sensor is suitable for Porsche 981/982/991/992 models. Compared with the original factory sensor, it has improved chip design, added packaging to the measuring core, soldered pins to the computer board, and changed the installation direction, making it relatively difficult to fall off. It has a sturdy aluminum alloy shell, is plug-and-play without coding, and costs one-tenth of the original price. After replacement, it not only eliminates fault codes but also restores the system to normal operation.

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