CAN Networking: Other Porsche Cayenne I рестайлинг

CAN 'Controller Area Network' (data processing network)

More and more systems in the vehicle must exchange data and this in turn requires fast and trouble-free data exchange. Control modules for various systems are connected to a 'two-wire network: high/low'. Since the amount of data that can be transferred over a network is limited, the control modules must be connected to several networks.

Three main data busses and one separate CAN data bus are used in the Cayenne. The umbrella term 'CAN data bus', which is used in these instructions to represent the individual 'CAN data busses', must be replaced by the relevant 'CAN data bus, e.g. CAN drive'.

These checking instructions are only relevant for the 'CAN data busses' listed below

1. CAN drive (CAN-C)
2. CAN Infotainment
3. CAN comfort (CAN-B)

The 'PSM control module' and the 'combination sensor' exchange messages via the 'CAN data bus' mentioned below.

1. CAN-internal

'Internal CAN' is a separate CAN data bus that does not have any physical links to the other CAN busses, i.e. 'CAN drive/CAN Infotainment/CAN comfort'.

General instructions/safety instructions

Fault code setting conditions

Fault codes can be set in several circumstances, e.g.

1. Battery disconnected
2. Plug connections disconnected
3. Incorrect coding
4. Voltage drop
5. etc.

In these circumstances, no fault is present in the system and the fault memory must be erased.

Possible causes of fault

Note. The 'possible causes of fault' that are responsible for the fault are listed here. Please note that in certain circumstances further faults can be stored in the fault memory after troubleshooting (e.g. if plugs are disconnected). After carrying out repairs, read out the fault memory of all control modules and erase any faults.

Causes of CAN faults

1. No or incorrect basic setting/adaption (control module)
2. Short circuit to B+ (CAN lead)
3. Short circuit to ground (CAN lead)
4. Short circuit with respect to each other (CAN lead)
5. Open circuit (CAN lead)
6. 'High' and 'low' confused (slot in connector, or wires separated and repaired incorrectly)

Fault status

The following status types are possible

1. present
2. not present

This information should be saved using the Save key [F4] and printed out.

Note. Visual inspection: During troubleshooting, please check first that the affected pins on the control module plug connection are neither damaged nor corroded. The wires and plugs of the affected components must also be checked for external damage and correct contact. Repair damaged or corroded pins if possible, otherwise replace affected pins. Repair or replace damaged wires.

Note. Battery positive voltage: A battery positive voltage of between 11.4 and 14.5 V is required for troubleshooting. This must be checked and ensured if necessary. Voltages must be ensured up to components or fuses (input side) on the vehicle electrical system.

Tools

Note. Plug contacts are optimally designed to suit the plug system. Operations on pins can cause contact problems. Always use suitable measurement tools for adapter plugs and test cables.

Scheme 254

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Scheme 261

Possible cause of fault

1. No data can be sent/received via CAN data bus (CAN data bus OFF)

One of the following errors is stored in all control units: CAN drive (high/low)/CAN infotainment (high/low)/CAN comfort OFF (high/ low)

Affected pins

The measurements to be taken are listed in the work instruction below. The measurements must be implemented using the 'pin assignment' shown in the table below, while taking the relevant 'control unit' and 'CAN data bus' into account.

PIN ASSIGNMENT