Here is a guide on using CGDI CG100X programmer or CG100 Prog III to reflash BCM lithium battery module. By following these instructions, you can disable the protection mode and restore the battery to its normal functioning.
When a Porsche Cayenne experiences a significant accident or the voltage of its 12V lithium battery drops too low, the battery enters a protective mode and becomes unchargeable. As a result, the vehicle fails to initiate, and replacing the battery becomes a costly endeavor.

The lithium battery has a label on its front side, which provides essential parameter details such as capacity, voltage, current, and production date.


To determine the voltage of the battery, a multimeter is utilized when the battery remains intact. If the measured voltage is 0V, it indicates that there is no voltage output from the battery. Consequently, the battery cannot be charged, and no current can be input into it.


Take off the battery cover


Take another reading of the battery's voltage.


Upon opening the battery case, there is no voltage output as the measured voltage remains at 0V.

To bypass the relay, which is connected in series in the positive direction, we continue measuring the voltage. The multimeter displays a reading of 1.92V, indicating that the battery does have voltage, but it is being blocked by the relay.

To locate the IC chip, simply open the upper case of the battery. This IC chip, produced by Freescale and identified as the SPC5644BMLU8 model, controls the overall operation of the battery.


The function of the battery relay is to be controlled by the BCM. In the event of a collision or when the battery voltage is too low, triggering the protection mode, the BCM cuts off the connection between the battery cell and the external battery terminal through the relay. This prevents battery over-discharge, which could lead to danger or battery damage. Consequently, the battery becomes unable to charge or discharge.


We take CG100 prog 3 for example, to repair a Porsche lithium battery using CG100, follow these steps: First, confirm the manufacturing year of the battery, such as 2018.


Next, launch the CG100 software and select the appropriate options: BCM - Porsche - lithium battery - Cayenne - 2018 - SPC5644B.


The software will display the wiring diagram.
Connect the battery to CG100 using the BCM4+ adapter, ensuring a proper and secure connection.




Click on 'Read' to retrieve the data.
Start by reading the PFLASH, followed by the DFLASH data. This process typically takes about 5 minutes, and it is crucial not to disconnect the device during the operation.


Save the original PFLASH and DFLASH data, which will be stored in a file containing both sets of data, with a file size of 1.56MB.



Proceed to write the data.
Click on 'Write' and follow these steps:
Write the PFLASH, verify the PFLASH, write the DFLASH, and verify the DFLASH.
CG100 software will handle the operation automatically, so patience is required for approximately 10 minutes.



Please take note that CG100X and CG100 software are equipped with updated PFLASH and DFLASH data specifically for 2018-2020 Porsche Cayenne models. These software versions automatically write the new data to the BCM battery during the repair process.

Once the repair is completed, it is recommended to test the voltage once again.

To test the voltage, connect it to an external voltage regulator.

By bypassing the relay, proceed to charge the battery using a precision regulated charger while continuously measuring the voltage throughout the charging process.


For charging purposes, a digitally controlled adjustable power supply can be used. Adjust the output mode to constant current output, starting with a small current (recommended below 3A) for the initial charging. Once the battery voltage surpasses 12V, switch to a larger current until the battery reaches full charge, calibrating the voltage.

Once the battery is charged to the regular voltage of 12V, disconnect the charger.


Reinstall the battery and measure the voltage once again.


With the battery fully charged, proceed to reinstall the battery case and tighten the screws.
Measure the voltage once more, which should now read 11.92V.
The battery repair has been successful.
Note: It is advisable to charge the battery for an additional hour using a high-power charger after installation in the vehicle.

CG100X /CG100 Porsche 12V lithium battery pinouts for 2017-2020 Cayenne SPC5644B


Porsche Taycan MM9Z1J638 pinouts.




Where to buy 2023 newest CGDI CG100X smart auto repair tool
https://www.cgdiprog.com/products/cgdi-cg100x-programmer-new.html