Operation CHARM: Car repair manuals for everyone.
Manuals through 2025 now available!

Our trusted friends have launched a new website named LEMON, which has newer manuals. It also contains all the CHARM manuals.

LEMON is the spiritual successor to CHARM, I recommend you try it!

Link: lemon-manuals.la or lemon-manuals.org.ua

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Input Signals



Input Signals

The following queries can be run using this menu item:
- 3 dB loss

NOTE: Deactivate the 'automatic traffic announcement' before performing the diagnosis on the PCM2. If this is not done, the diagnosis will abort.

Menu item Function

- 3 dB loss Under this menu item, it is possible to check the electrical and optical MOST during troubleshooting.
- Connect and start the 9588 Porsche System Tester II and switch on the ignition.
- Select '911 (996)' in the Vehicle type menu and confirm with the [>>] key.
- Select 'PCM' in the Control modules menu and confirm with the [>>] key.
- Select 'External Harman amplifier' in the 911 (996) PCM2 function selection and confirm with the [>>] key.
- Select 'Input signals' in the 911 (996) external Harman amplifier function selection and confirm with the [>>] key.
- Select "3dB lowering" in the external Harman amplifier input signals function selection using the [>] key and confirm with the [>>] key.
- Read out values from the display field.