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MOST Component Check



MOST Component Check

NOTE: When there is a customer complaint or identifiable problems but no fault code entries, firstly the 'MOST component check' is to be selected in the PCM2 function selection menu and then the 'MOST system check' is to be carried out.

The MOST component check can be reached via the menu PCM2 function selection. This comprises a summary of the following check processes:
- MOST System check (ignition on.)
- Diagnosis, ring break diagnosis (ignition on.)
- Optical performance check.
- Data transmission check.
- MOST system check (with engine running).
- Ring break diagnosis (with engine running).

The MOST components check 'MOST system check' is to be carried out when the display indicates 'unavailable MOST control modules'. If no fault code is stored, the '*' symbol indicates a 'varying required and actual installed components list' in the Control modules menu in front of the 'PCM2' system and in the 'PCM2 MMI function selection' in front of the selection 'MOST required installed components list'. A comparison of these two lists can determine missing components.

MOST System check (ignition on.)
This check must only be carried out when the engine is not running.

Menu item Function

- MOST System check Using this menu item, a MOST system
(ignition on.) check can be carried out with the ignition on. The following checks are carried out automatically and their results are displayed.
- Gateway start-up condition is read out.
- MOST installed components list (required and actual installed components list) is analysed.
- Start the ring break diagnosis.
- The results are displayed by the 9588 Porsche System Tester II

- 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 'PCM2' in the Control modules menu and confirm with the [>>] key.
- Select 'MOST components check' in the PCM2 function selection and confirm with the [>>] key.
- Select "MOST system check (ignition on)" in the 911 (996) PCM MOST components check function selection and confirm with the [>>] key.

Diagnosis, open circuit in distribution line (ignition on.)
This check must only be carried out when the engine is not running.

Menu item Function

- Diagnosis, ring break The ring break diagnosis
diagnosis (ignition on.) carries out the following checks:
- Gateway start-up condition is read out.
- MOST installed components list (required and actual installed components list) is analysed.
- Start the ring break diagnosis.
- The results are displayed by the 9588 Porsche System Tester II
- 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 'PCM2' in the Control modules menu and confirm with the [>>] key.
- Select 'MOST components check' in the PCM2 function selection and confirm with the [>>] key.
- Select "Ring break diagnosis (top)" in the 911 (996) PCM MOST components check function selection and confirm with the [>>] key.
- Follow the Tester instructions.

Optical performance check

Menu item Function

- Optical performance check The optical performance check allows the performance of the MOST to be checked optically. The following checks are carried out automatically:
- MOST installed components list (required and actual installed components list) is analysed.
- External MOST components display.
- Carrying out the performance check.
- The result is displayed by the tester.
- 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 'PCM2' in the Control modules menu and confirm with the [>>] key.
- Select 'MOST components check' in the PCM2 function selection and confirm with the [>>] key.
- Select "Optical performance check" in the 911 (996) PCM2 MOST components check function selection and confirm with the [>>] key.
- Follow the Tester instructions.

Data transmission check

Menu item Function
- Data transmission check Using this menu item, the quality of the data transmission can be assessed.
This is a counter which leads to an increase in the value if faults occur within a certain time period. The check is carried out continuously at predetermined intervals.
- 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 'PCM2' in the Control modules menu and confirm with the [>>] key.
- Select 'MOST components check' in the PCM2 function selection and confirm with the [>>] key.
- Select "Data transmission check" in the 911 (996) PCM2 MOST components check function selection and confirm with the [>>] key.

MOST system check (with engine running)

Menu item Function

- MOST system check Using this menu item, the quality of the
(with engine running). data transmission can be assessed. This is a counter which leads to an increase in the value if faults occur within a certain time period. The check is carried out continuously at predetermined intervals.
- Gateway start-up condition is read out.
- MOST installed components list (required and actual installed components list) is analysed.
- Ring line diagnosis.
- 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 'PCM2' in the Control modules menu and confirm with the [>>] key.
- Select 'MOST components check' in the PCM2 function selection and confirm with the [>>] key.
- Select "MOST system check (bottom)" in the 911 (996) PCM2 MOST components check function selection and confirm with the [>>] key.
- Follow the Tester instructions.

Whenever there are several ring breaks, the 1st ring break is displayed in the following order:
- PCM2 Gateway [>] external amplifier.
- External amplifier[>] CD changer.
- CD changer [>] telephone.
- Telephone [>] PCM2 MMI is displayed. Then the check is terminated.
- Start the optical performance check.

Ring break diagnosis (with engine running)

Menu item Function

- Ring break diagnosis Using this menu item, a ring break
(with engine running). diagnosis can be carried out (with the engine running).
- 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 'PCM2' in the Control modules menu and confirm with the [>>] key.
- Select 'PCM2 GW' in the PCM2 function selection and confirm with the [>>] key.
- Select 'MOST components check' in the PCM2 GW function selection and confirm with the [>>] key.
- Select "Ring break diagnosis (when the engine is running)" in the 911 (996) PCM2-GW MOST components check function selection and confirm with the [>>] key.
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