ARTICLE BEGINNING CAN NETWORKING -...

ARTICLE BEGINNING

CAN NETWORKING

INTRODUCTION

CAN networking

Cayenne model year 2003

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:

� CAN drive (CAN-C)

� CAN Infotainment

� CAN comfort (CAN-B)

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

� 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

CAUTION: Danger of damage due to improper handling of batteries and control module plug connections!

� Never disconnect battery with engine running.

� Never start engine if battery terminal clamps are notconnected securely.

� Never pull off or push on plug connections for the control

of 18CAN NETWORKING -2004 Porsche Cayenne S

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Fault code setting conditions

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

� Battery disconnected

� Plug connections disconnected

� Incorrect coding

� Voltage drop

� etc.

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

Troubleshooting procedure

Troubleshooting can only be performed when the fault is present. In other words, specific troubleshooting can only be performed in accordance with instructions (given under

Diagnosis/troubleshooting for each fault code) if the entry has the status 'present' in the fault memory.

If the fault is currently 'not present', please check the following:

� Diagnostic conditions are met

� All plug connections and ground points of the affected current path are OK

� View the fault frequency counter in the Porsche System Tester II No. 9588 using the fault

memory Info key [F8] under 'Extended fault memory' and try to reach conclusions about eliminating any loose contacts in the system.

Diagnostic conditions

modules or other electronic components when the ignition is switched on

� Always disconnect the negative terminal of the battery and pull off all plug connections to the vehicle electrical systemcontrol module when carrying out welding work on the vehicle

CAUTION: Danger of injury and damage due to unusual vehicle handling when plugs or components are disconnected!

� Never disconnect plugs when the vehicle is in motion ordrive the vehicle with plugs disconnected.

� Drive only with all parts fully installed and connected.

IMPORTANT: Always connect a suitable battery charging device to the vehicle electrical system battery before starting diagnosis. All unnecessary loads must also be switched off.



1. Erase fault memory

2. Satisfy the requirements listed under 'Diagnostic conditions'

3. Read out fault memory again

Possible causes of fault

Causes of CAN faults:

� No or incorrect basic setting/adaption (control module)

� Short circuit to B+ (CAN lead)

� Short circuit to ground (CAN lead)

� Short circuit with respect to each other (CAN lead)

� Open circuit (CAN lead)

� 'High' and 'low' confused (slot in connector, or wires separated and repaired incorrectly)

Diagnosis/troubleshooting

Possible fault types:

� no signal/communication

� implausible signal/please read out fault memory

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

Fault status

The following status types are possible:

� present

� not present

NOTE: The fault can only be identified if the requirements listed under 'Diagnostic conditions' are met. For this reason, the specified procedure must be observed after a fault is repaired:

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.

NOTE: The fault memory Info key [F8] on Porsche System Tester II No. 9588 can be used to access the 'extended fault memory'. The following information can be displayed:



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

TOOLS

BATTERY CHARGING DEVICE

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.

WARNING: Danger of personal injury while driving with special tools

� 9588 Never hang the Porsche System Tester II over the steering wheel

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.



Fig. 1: Identifying Battery Charging Device

Courtesy of PORSCHE OF NORTH AMERICA. INC.

9588 Porsche System Tester II

Fig. 2: Identifying 9588 Porsche System Tester IICourtesy of PORSCHE OF NORTH AMERICA. INC.

COMMERCIALLY AVAILABLE DIGITAL MULTIMETER



Fig. 3: Identifying Commercially Available Digital Multimeter




9684 MEASUREMENT TOOL SET

Fig. 4: Identifying 9684 Measurement Tool SetCourtesy of PORSCHE OF NORTH AMERICA. INC.

COMPONENT ARRANGEMENT

CAN DRIVE (CAN-C)



Fig. 5: Identifying Component Arrangement Of CAN Drive (CAN-C)


CAN COMFORT (CAN-B)



Fig. 6: Identifying Component Arrangement Of CAN Comfort (CAN-B)




CAN INFOTAINMENT

Fig. 7: Identifying Component Arrangement Of CAN Infotainment


CAN-INTERNAL



Fig. 8: Identifying Component Arrangement Of CAN-Internal


CHECKING INSTRUCTIONS/CAN DATA BUS

DIAGNOSTIC CONDITIONS

� Ignition on

� Internal control unit function test

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)



Use the table 'Cause of fault 1' for troubleshooting!

� short circuit to B+

� short circuit to ground

� Short circuit with respect to each other ('high' and 'low' lines)

� Confused 'high' and 'low' lines (wrong slot in connector, or faulty lines confused during repairs)

2. Expected control unit message missing/no communication possible with control unit:

Read out the fault memory in the gateway and localize the error via the stored error using the CAN topologyg, refer to 97 IN WIRING DIAGRAM FOR CAYENNE (9PA) '03 MODEL - AS OF

MY 2003 (CAYENNE TIP, CAYENNE MAN, CAYENNE S TIP, CAYENNE S MAN, CAYENNE TURBO) , or 97 IN WIRING DIAGRAM FOR CAYENNE (9PA) MODEL YEAR

'04 - AS OF MY 2004 (CAYENNE TIP, CAYENNE MAN, CAYENNE S TIP, CAYENNE S

MAN, CAYENNE TURBO) Circuit diagram.

Use the table 'Cause of fault 2' for troubleshooting!

� The corresponding control unit does not have a power/ground supply

� The corresponding control unit does not function

� CAN data bus on affected control unit interrupted

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 'controlunit' and 'CAN data bus' into account.

PIN ASSIGNMENT

Control unitCAN drive (C)

CAN comfort (B)

CAN Infotainment

CANinternal

(high) (low) (high) (low) (high) (low) (high) (low)

1 Airbags A3 A2

2 Trailer hitch B7 B8

3Vehicle electrical system

A1 A2

4 DME A60 A58

5 KESSY A22 A21 A24 A23

6Air-conditioning control unit, front

C17 C18

7Air-conditioning

control unit, rearC17 C18

8 Instrument clusterB19/External

B8B20/External

B9B27 B28 B31 B32



DIAGNOSIS/TROUBLESHOOTING, CAN DATA BUS

Cause of error '1', no data can be sent/received via CAN data bus (CAN data bus OFF):

9Combination sensor

A4 A2

10Rear convenience system

B2 B8

11

Compass

(magnetic fieldsensor)

A5 A3

12

Steering column

switch withsteering-angle sensor

A10 A11 A9 A8

13Memory seat adjustment, driver's

F1 F4

14Memory seat adjustment,passenger's

F1 F4

15 Level adjustment A61 A81

16 Offroad stabilisers B1 B3

17Panorama roof system

A5 A10

18 ParkAssist A2 A3

19 PCM2/CDR23 C1 C2

20 PSM A11 A15 A29 A25

21Rear-differential

lockA42 all

22Tyre pressure monitoring

A15 A31

23 Tiptronic A46 A34

24 Rear left door D2 D7

25 Rear right door D2 D7

26 Driver's door D2 D7

27 Passenger's door D2 D7

28 Transfer box A42 A11

29 Wiper motor A7 A8

30 Auxiliary heater A2 A3

NOTE: Faults can only be located quickly and effectively with the help of the 'CAN topology' and 'CAN networking'.

NOTE: In the event of line problems, refer to 97 09 49 REWORKING MAIN WIRE HARNESS - AS OF MY 2003 (ALL MODELS) .



DIAGNOSIS/TROUBLESHOOTING PROCEDURE FOR CAN DATA BUS

Work instruction Display OK If not OK

1

Check control units using the 9588 Porsche System Tester II Absolutely

essential for fault delimitation: CANtopology/networkingg, refer to 97 IN WIRING

DIAGRAM FOR

CAYENNE (9PA) '03 MODEL - AS OF MY

2003 (CAYENNE TIP,

CAYENNE MAN,

CAYENNE S TIP, CAYENNE S MAN,

CAYENNE TURBO) , or 97 IN WIRING DIAGRAM FOR

CAYENNE (9PA)

MODEL YEAR '04 - AS

OF MY 2004 (CAYENNETIP, CAYENNE MAN,

CAYENNE S TIP,

CAYENNE S MAN, CAYENNE TURBO)

Circuit diagram.

� Connect the 9588Porsche System Tester II

to the diagnostic socket and leave it connected.

� Read out fault memory of all control units connected to the faulty 'CAN data bus'.

� Use the component arrangement and CAN

topology/networking as an aidg, refer to 97 IN

WIRING DIAGRAM

FOR CAYENNE (9PA) '03 MODEL - AS OF

MY 2003 (CAYENNE

TIP, CAYENNE MAN,


CAYENNE TURBO) ,

or 97 IN WIRING DIAGRAM FOR

CAYENNE (9PA)

MODEL YEAR '04 -

AS OF MY 2004 (CAYENNE TIP,

CAYENNE MAN,


CAYENNE TURBO)

Circuit diagram. Circuit diagram pick out the affected control units.

� Switch off ignition

� Start with the most easily accessible control unit.

� Pull off the plug on the first control unit.

� Switch on ignition

� Read out the fault memory of the remaining control units andestablish whether the

fault is still present.

� If the fault is still present after disconnecting the

A 'CAN data bus fault' is

still stored in the fault memory of the control

unit that was disconnectedfirst. The fault is not caused by a control unit.Refer to Step 2

The fault is no longer present after the last control unit is disconnected.

No 'CAN data bus faults' are stored in the fault memory

of the control unit that was disconnected first.The control unit that was disconnected last is faulty and must bereplaced.

End



first control unit, the control unit is not responsible for causing the fault.


� Re-connect the disconnected control unit.

� Disconnect the nextcontrol unit and check the

fault memory in the same way as on the first control unit. The control unit remains disconnected and is not plugged in again.

� The procedure for all the control units below is the

same as for the second control unit until the circuit to the first controlunit is closed.

2

Check whether (high) and (low) lines are confused in CAN data bus. Absolutely

essential for fault delimitation: CANtopology/networkingg, refer to 97 IN WIRING DIAGRAM FOR

CAYENNE (9PA) '03

MODEL - AS OF MY

2003 (CAYENNE TIP, CAYENNE MAN,

CAYENNE S TIP,

CAYENNE S MAN, CAYENNE TURBO) , or 97 IN WIRING

DIAGRAM FOR

CAYENNE (9PA) MODEL YEAR '04 - AS

OF MY 2004 (CAYENNE

TIP, CAYENNE MAN, CAYENNE S TIP,

CAYENNE S MAN,

CAYENNE TURBO)

Circuit diagram.


� All control units are disconnected.

� Check the slot for the lines in each plug on the basis of 'pin assignment'

and 'cable colours'.

� Measure resistance

between control unit plug (...) 'CAN data bus(low)' / 'CAN data bus (high)' on 'pin (...)' and

each individual plug on the disconnected control units 'CAN data bus (low)' / 'CAN data bus(high)' on 'pin (...)'.

If the visualinspection based on

cable colours and pin assignments as well as

resistance measurement did not show any faults:< 5 ΩRefer to Step 3

Repair wire harness→ End

Refer to WIRING .

Check CAN data bus (high)

� All control units are

disconnected from the CAN data bus.

� Switch on ignition < 0.3 VRepair wire harness



Cause of error '2', expected control unit message missing/no communication possible with

control unit:

DIAGNOSIS/TROUBLESHOOTING PROCEDURE

3

for short circuit to B+� Measure voltage between

control unit plug (...) 'CAN data bus (high)' on 'pin (...)' and ground.

Refer to Step4

→ EndRefer to WIRING

4Check CAN data bus (low) for short circuit to B+

� Measure voltage between control unit plug (...) 'CAN data bus (low)' on

'pin (...)' and ground.

< 0.3 VRefer to Step 5

Repair wire harness→ EndRefer to WIRING

5Check CAN data bus (high) for short circuit to ground


� Measure resistance

between control unit plug (...) 'CAN data bus (high)' on 'pin (...)' and ground.

∞ ΩRefer to Step 6


6Check CAN data bus (low) for short circuit to ground

� Measure resistance between control unit plug

(...) 'CAN data bus (low)' on 'pin (...)' and ground.

∞ ΩRefer to Step 7

Repair wire harness→ EndRefer to

WIRING

7

Check CAN data bus (high) and CAN data bus (low) for short circuit with respect to each other

� Measure resistance on control unit plug (...) between 'CAN data bus (high)' 'pin (...)' and 'CAN

data bus (low)' 'pin (...)'.


NOTE:� Before replacing the control unit, the ground connections, power

supply and plug connections on the control unit must be checked.

� When replacing the control unit, observe the coding.

� After the test drive, read out the fault memory with the 9588 Porsche System Tester II again. Additional causes of faults that could damage the control unit should be detected and remedied.

Work instruction Display OK If not OK

1Check power/ground supply in control unit and correct coding

� Switch on ignition

� Check coding of affected controlunit.

� Check functionality of

the control unit.

Communication with control unit OK.Refer to Step 2

Code the control unit or

troubleshoot the specific system with no control unit

connected .End



2

Check CAN data bus (high) for open circuit.

Absolutely essential for fault delimitation: CANtopology/networking, refer to 97

IN WIRING DIAGRAM FOR CAYENNE (9PA) '03 MODEL -

AS OF MY 2003 (CAYENNE

TIP, CAYENNE MAN,

CAYENNE S TIP, CAYENNE S MAN, CAYENNE TURBO) , or 97 IN WIRING DIAGRAM

FOR CAYENNE (9PA) MODEL YEAR '04 - AS OF

MY 2004 (CAYENNE TIP,

CAYENNE MAN, CAYENNE S

TIP, CAYENNE S MAN, CAYENNE TURBO) Circuitdiagram.

� Switch off

ignition

� Only pull off the plugs on control units that are connected to andexchange messages with

the affected 'CAN data bus'.

� Measureresistance between control unit plug (stored fault code) 'CAN data bus (high)' on 'pin (...)' and each plug on the disconnected

control units'CAN data bus (high)' on 'pin (...)'.

< 5 ΩRefer to Step 3

Repair wire harness→ EndRefer to WIRING .

3

Check CAN data bus (low) for open circuit.Absolutely essential for fault

delimitation: CANtopology/networking, refer to 97

IN WIRING DIAGRAM FOR

CAYENNE (9PA) '03 MODEL -

AS OF MY 2003 (CAYENNE TIP, CAYENNE MAN,

CAYENNE S TIP, CAYENNE S

MAN, CAYENNE TURBO) , or 97 IN WIRING DIAGRAM

FOR CAYENNE (9PA)

MODEL YEAR '04 - AS OF

MY 2004 (CAYENNE TIP, CAYENNE MAN, CAYENNE S

TIP, CAYENNE S MAN,

CAYENNE TURBO) Circuitdiagram.

� Measure resistancebetween control unit plug (stored

fault code) 'CAN data bus (low)' on 'pin (...)' and each plug on the

disconnected control units 'CAN data bus (low)' on 'pin (...)'.

< 5 ΩRefer to Step 4

Repair wire harness

Refer toWIRING .

→ End

4 Replace control unit

The control unit which does not

transmit a message is affected (see stored error code)Observe upper instruction onexchanging control units→ End



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