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Transfer Box: Diagnosis Porsche Cayenne I

Transfer Case ~3751 words

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

  1. Diagnostic conditions are met
  2. All plug connections and ground points of the affected current path are OK
  3. 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

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

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

  1. Erase fault memory
  2. Satisfy the requirements listed under 'Diagnostic conditions'.
  3. Read out fault memory again.

Diagnosis/troubleshooting

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

  1. Ignition on
  2. Internal transfer box control module function test

Note. Visual inspection: In the next troubleshooting section, please check first that the affected 'pin' of the transfer box control unit plug connection and the 'pin' of the plug connections are neither damaged nor corroded. Remove any soiling or corrosion/oxidation. Replace damaged parts/wires.

Note. Control unit replacement: Before replacing the 'transfer box control unit', the ground connections, power supply and plug connections on the control unit must be checked as OK. 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 'transfer box control unit' should be detected and remedied.

Before carrying out the work instruction, check fuse '57', voltage supply terminal 30 for the transfer box control unit, in the fuse carrier to the right of the dashboard and replace if necessary. After replacing the fuse, determine and remedy the cause of the fault in accordance with the work instruction below!

Work instructionDisplay OKIf not OK
1Check battery voltage/current and charge voltage/current on three-phase generatorEngine speed > 2,000 rpm. Measure charge voltage/current of generator.11.4 to 14.5 V Go to Step 2Charge battery if necessary, replace if faulty. Wiring/regulator or diodes faulty. Repair wiring or generator. After carrying out repairs, erase the fault memory and then read out the fault memory again while observing the diagnostic conditions. If no fault stored, then: --> End If fault reappears, then: Go to Step 2
2Check terminal 30 voltage supply and ground supply line to transfer box control unitMeasurement '2a': Ignition off Pull plug off the transfer box control unit Measure voltage between 'pin 46' and ground on transfer box control unit plug.10.5 to 14.5 V continue with measurement '2b'Check fuse '57' in fuse carrier at right of dashboard (resistance measurement). Check voltage supply line for short circuit to ground: Go to Step 3
Measurement '2b': Measure voltage between 'pin 47' and battery terminal 30 on transfer box control unit plug.10.5 to 14.5 V Go to Step 3Check ground supply line for short circuit to B+: Go to Step 3
3Check power supply line for short circuit to groundMeasurement '3a': Measure voltage between 'pin 46 and battery positive' on transfer box control unit plug.< 0.3 V Measurement '3b'Short circuit to ground between transfer box control unit plug leads 'pin 46 and fuse 57' in fuse carrier at right of dashboard. Repair wiring and replace faulty fuse. --> End
Check ground supply line for short circuit to B+Measurement '3b': Measure voltage between 'pin 47' and ground on transfer box control unit plug.< 0.3 V Go to Step 4Short circuit to B+ between transfer box control unit plug leads 'pin 47' and ground pin MB26. Repair wiring and replace faulty fuse(s). --> End
4Check for open circuit of terminal 30 voltage supply line and ground supply line for ground pin MB26Measure resistance on transfer box control unit plug between 'pin 46 and fuse 57' in fuse carrier at right of dashboard. Measure resistance between 'pin 47' and ground pin MB26 on transfer box control unit plug.< 0.5 ohms Go to Step 5Open circuit in wire to fuse carrier at right of dashboard. Open circuit in wire to ground pin MB26. Repair wire(s). Also check fuse. --> End
5Check terminal 30 power supply at fuseMeasure voltage between fuse plug '57 and body ground' in fuse carrier at right of dashboard.10.5 V to 14.5 V Go to Step 6Short circuit/contact resistance/corroded or loose connections near or in fuse carrier. Repair if possible, otherwise replace fuse carrier at right of dashboard. --> End
6Replace transfer box control moduleSee note on replacing control units! --> End

DIAGNOSIS TROUBLESHOOTING PROCEDURE

  1. Ignition on
  2. Internal control module function test not completed successfully

Diagnosis/troubleshooting VG 0101

Note. Before replacing the control module, the ground connections, power supply and plug connections on the control module must be checked. After the test drive, read out the fault memory again with the Porsche System Tester II No. 9588. Additional causes of faults that could damage the transfer box control module should be detected and remedied.

Work instructionDisplay OKIf not OK
1Delete the fault memory for the transfer box control module and restart the internal function test (ignition ON/test is performed automatically)> EndGo to Step 2
2Replace transfer box control module> End

DIAGNOSIS TROUBLESHOOTING PROCEDURE

  1. Ignition on
  2. Internal control module function test

Note. If there is no incoming signal/message via the CAN drive using several control modules, the CAN drive must be checked for open or short circuits. Refer to ' CHECKING INSTRUCTIONS/CAN DATA BUS '.

Work instructionDisplay OKIf not OK
1Read out fault memory for steering column switch (fault localisation)For further fault localisation, please follow the diagnosis/troubleshooting instructions for the PSM control module, refer to the ANTI-LOCK BRAKE SYSTEM (ABS) article . The troubleshooting description '0778 Steering-angle sensor' must be used from this. --> End
2CHECKING INSTRUCTIONS/CAN DATA BUS .> End

DIAGNOSIS TROUBLESHOOTING PROCEDURE

  1. Ignition on
  2. Internal transfer box control module function test

Note. If there is no incoming signal/message via the CAN drive using several control modules, the CAN drive must be checked for open or short circuits. Refer to ' CHECKING INSTRUCTIONS/CAN DATA BUS '.

Work instructionDisplay OKIf not OK
1CHECKING INSTRUCTIONS/CAN DATA BUS .> End

DIAGNOSIS TROUBLESHOOTING PROCEDURE

  1. Ignition on
  2. Internal control module function test

Note. If there is no incoming signal/message via the CAN drive using several control modules, the CAN drive must be checked for open or short circuits. Refer to ' CHECKING INSTRUCTIONS/CAN DATA BUS '.

Work instructionDisplay OKIf not OK
1Read out fault memory for DME control module (fault localisation)To eliminate further faults, please follow the diagnosis/troubleshooting instructions for the DME control module, refer to the OBD (II) and FUEL SYSTEM, ELECTRONIC INJECTION articles . --> End
2CHECKING INSTRUCTIONS/CAN DATA BUS .> End

DIAGNOSIS TROUBLESHOOTING PROCEDURE

  1. Ignition on
  2. Internal control module function test

Note. If there is no incoming signal/message via the CAN drive using several control modules, the CAN drive must be checked for open or short circuits. Refer to ' CHECKING INSTRUCTIONS/CAN DATA BUS '.

Work instructionDisplay OKIf not OK
1Read out fault memory for Tiptronic control module (fault localisation)For further fault localisation, please follow the diagnosis/troubleshooting instructions for the Tiptronic control module, refer to the TIPTRONIC and AUTOMATIC - ACTUATION, ASSEMBLY HOUSING articles. . --> End
2CHECKING INSTRUCTIONS/CAN DATA BUS .> End

DIAGNOSIS TROUBLESHOOTING PROCEDURE

  1. Ignition on
  2. Internal control module function test
  3. Vehicle speed greater than 0 km/h

Note. If there is no incoming signal/message via the CAN drive using several control modules, the CAN drive must be checked for open or short circuits. Refer to ' CHECKING INSTRUCTIONS/CAN DATA BUS '.

Work instructionDisplay OKIf not OK
1Read out fault memory for PSM control module (fault localisation)To eliminate further faults, please follow the diagnosis/troubleshooting instructions for the PSM control module, refer to the ANTI-LOCK BRAKE SYSTEM (ABS) article . --> End
2CHECKING INSTRUCTIONS/CAN DATA BUS .> End

DIAGNOSIS TROUBLESHOOTING PROCEDURE

  1. Ignition on
  2. Internal control module function test

Note. If there is no incoming signal/message via the CAN drive using several control modules, the CAN drive must be checked for open or short circuits. Refer to ' CHECKING INSTRUCTIONS/CAN DATA BUS '.

Work instructionDisplay OKIf not OK
1Read out instrument cluster fault memoryFor further troubleshooting, please follow the diagnosis instructions for the instrument cluster, refer to the INSTRUMENT CLUSTER article . --> End
2CHECKING INSTRUCTIONS/CAN DATA BUS .> End

DIAGNOSIS TROUBLESHOOTING PROCEDURE

  1. Ignition on
  2. Internal control module function test
Work instructionDisplay OKIf not OK
1Read out fault memory for gateway (in instrument cluster) (fault localisation)For further fault localisation, please follow the diagnosis/ troubleshooting instructions for the gateway (in instrument cluster), refer to the INSTRUMENT CLUSTER article . --> End
2CHECKING INSTRUCTIONS/CAN DATA BUS .> End

DIAGNOSIS TROUBLESHOOTING PROCEDURE

  1. Ignition on
  2. Internal transfer box control module function test

Note. Before replacing the control module, the ground connections, power supply and plug connections on the control module must be checked. After the test drive, read out the fault memory again with the Porsche System Tester II No. 9588. Additional causes of faults that could damage the transfer box control module should be detected and remedied.

Work instructionDisplay OKIf not OK
1Replace transfer box control module> End

DIAGNOSIS TROUBLESHOOTING PROCEDURE

  1. Ignition on
  2. Internal transfer box control module function test

Note. Before replacing the control module, the ground connections, power supply and plug connections on the control module must be checked. After the test drive, read out the fault memory again with the Porsche System Tester II No. 9588. Additional causes of faults that could damage the transfer box control module should be detected and remedied.

Work instructionDisplay OKIf not OK
1Replace transfer box control module> End

DIAGNOSIS TROUBLESHOOTING PROCEDURE

  1. Ignition on
  2. Internal transfer box control module function test

Note. Before replacing the control module, the ground connections, power supply and plug connections on the control module must be checked. After the test drive, read out the fault memory again with the Porsche System Tester II No. 9588. Additional causes of faults that could damage the transfer box control module should be detected and remedied.

Work instructionDisplay OKIf not OK
1Replace transfer box control module> End

DIAGNOSIS TROUBLESHOOTING PROCEDURE

Note. The internal function test must be completed successfully before the functions stored in the transfer box control unit can be activated.

  1. Ignition on
  2. Internal transfer box control unit function test

Note. Before replacing the control unit, the ground connections, power supply and plug connections on the control unit must be checked. After the test drive, read out the fault memory with the Porsche System Tester II No. 9588 again. Additional causes of faults that could damage the transfer box control unit should be detected and remedied.

Work instructionDisplay OKIf not OK
1Delete the fault memory for the transfer box control unit and restart the internal function test (ignition ON/test is performed automatically)> EndIf fault is repeated, then: Go to Step 2
2Replace transfer box control unit> End

DIAGNOSIS TROUBLESHOOTING PROCEDURE

Note. The internal function test must be completed successfully before the functions stored in the transfer box control unit can be activated.

  1. Ignition on
  2. Internal transfer box control unit function test

Note. Before replacing the control unit, the ground connections, power supply and plug connections on the control unit must be checked. After the test drive, read out the fault memory with the Porsche System Tester II No. 9588 again. Additional causes of faults that could damage the transfer box control unit should be detected and remedied.

Work instructionDisplay OKIf not OK
1Delete the fault memory for the transfer box control unit and restart the internal function test (ignition ON/test is performed automatically)> EndIf fault is repeated, then: Go to Step 2
2Replace transfer box control unit> End

DIAGNOSIS TROUBLESHOOTING PROCEDURE

  1. Ignition on
  2. Internal function test on transfer box control unit

Note. Visual inspection: In the next troubleshooting section, please check first that the affected 'pins' on the transfer box control unit plug connection and the 'pins' on the plug connections on the 'selector switch (in running gear control module)' are neither damaged nor corroded. Remove any soiling or corrosion/oxidation. Replace damaged parts/wiring.

Note. Control unit replacement: before replacing the 'transfer box control unit', the ground connections, power supply and plug connections on the control unit must be checked and found to be OK. After test-driving the vehicle, read out the fault memory again using the 9718 PIWIS tester. Additional causes of faults that could damage the 'transfer box control unit' should be detected and remedied.

Work instructionDisplay OKIf not OK
1Carry out the following checks on the wiring between 'pin 7' 'transfer box control unit' and 'pin 4' 'selector switch (in running gear control module)': Short circuit to B+ Short circuit to ground Open circuitGo to Step 2Repair or replace connector/wiring. --> End
2Replace selector switch (running gear control module)> End

DIAGNOSIS TROUBLESHOOTING PROCEDURE

Note. This fault code relates to the signal of potentiometer '2' (sensor 2) which, together with potentiometer '1' (sensor 1) and the temperature sensor, is integrated as a unit in the servo motor.

  1. Ignition on
  2. Internal transfer box control module function test

Note. Visual inspection: In the next troubleshooting section, please check first that the affected 'pins' of the transfer box control unit plug connection and the 'pins' of the plug connections on the servo motor are neither damaged nor corroded. Remove any soiling or corrosion/oxidation. Replace damaged parts/wires.

Note. Control unit replacement: Before replacing the 'transfer box control unit', the ground connections, power supply and plug connections on the control unit must be checked as OK. Please observe the coding of the control module. 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 'transfer box control unit' should be detected and remedied.

Troubleshooting fault type: 'short circuit to B+'

Work instructionDisplay OKIf not OK
1Check short circuit to B+Measurement '1a': Ignition off Pull plug off the transfer box control unit Ignition on Measure voltage between 'pin 31' of transfer box control unit plug and ground.< 0.3 V go to measurement '1b'Repair wiring harness to servo motor. --> End
Measurement '1b': Ignition off Pull plugs 'A' and 'B' off servo motor Measure resistance between 'pin B8 and pins A1, A2, A3, A4' of servo motor plugs 'A and B'. Measure resistance between 'pin B8 and pin B4' of servo motor plug 'B'.Infinity ohms go to measurement '1c'Short circuit between servo motor leads. Go to Step 2
Measurement '1c': Measure resistance between 'pin 31' and pins '1, 15, 16, 18, 21, 36' of transfer box control unit plug.Infinity ohms Go to Step 3Repair wiring harness to servo motor. --> End
2Replace transfer box servo motor> End
3Replace transfer box control moduleSee note on replacing control units! --> End

DIAGNOSIS TROUBLESHOOTING PROCEDURE

Troubleshooting fault type: 'Open circuit/short circuit to ground'

Work instructionDisplay OKIf not OK
1Check short circuit to groundMeasurement '1a': Ignition off Pull plug off transfer box control unit Measure resistance between 'pin 31 and pins 2, 15, 16, 44, 47' of transfer box control unit plug.Infinity ohms Go to Step 2Go to measurement '1b'
Measurement '1b': Pull plugs 'A' and 'B' off servo motor Measure resistance between 'pin 31 and pins 2, 15, 16, 33, 44, 47' of transfer box control unit plug.Infinity ohms Go to Step 3Repair wiring harness to servo motor. --> End
2Check open circuitMeasurement '2a': Pull plug 'B' off servo motor Measure resistance between 'pin B8' and 'pin B10' of servo motor plug 'B'.1.1 to 2.2 kohms go to measurement '2b'Go to Step 3
Measurement '2b': Measure resistance between 'pin 31' of transfer box control unit plug and 'pin B8' of removed sensor plug 'B'.< 5 ohms Go to Step 4Repair wiring harness to servo motor. --> End
3Replace transfer box servo motor> End
4Replace transfer box control moduleSee note on replacing control units! --> End

DIAGNOSIS TROUBLESHOOTING PROCEDURE

  1. Ignition on
  2. Internal transfer box control unit function test

Note. Visual inspection: In the next troubleshooting section, please check first that the affected 'pins' of the transfer box control unit plug connection and the 'pins' of the plug connections on the servo motor are neither damaged nor corroded. Remove any soiling or corrosion/oxidation. Replace damaged parts/wires.

Note. Control unit replacement: Before replacing the 'transfer box control unit', the ground connections, power supply and plug connections on the control unit must be checked as OK. Please observe the coding of the control unit. After the test drive, read out the fault memory again with the Porsche System Tester II No. 9588. Additional causes of faults that could damage the 'transfer box control unit' should be detected and remedied.

Work instructionDisplay OKIf not OK
1Check voltage supply of potentiometer '1' and potentiometer '2'Ignition off Pull sensor plug 'B' off servo motor Ignition on Measure voltage at sensor plug 'B' on the wiring harness side between: 'pin B4 and pin B3', 'pin B10 and pin B9' and 'pin B6 and ground'.Approx. 5 V Go to Step 2, measurement '2a'Measured voltage > 5 V Go to Step 2, measurement '2b' Measured voltage < 5 V Go to Step 3
2Check short circuit to B+Measurement '2a': Ignition off Pull plug 'A' off servo motor Measure resistance at servo motor plugs 'A and B' between: 'pin B10 and pin A1, A2, A3, A4', 'pin B4 and pin A1, A2, A3, A4' and 'pin B6 and pin A1, A2, A3, A4'.Infinity ohms Measurement '2b'Short circuit between servo motor leads. Go to Step 4
Measurement '2b': Ignition off Pull plug 'A' off servo motor Pull plug off transfer box control unit Ignition on Measure voltage between 'pins 1, 18, 29' of transfer box control unit plug and ground.< 0.3 V Measurement '2c'Repair wiring harness to servo motor. --> End
Measurement '2c': Ignition off Measure resistance at transfer box control unit plug between 'pin 1 and pin 15, 16, 21, 36', 'pin 18 and pin 15, 16, 21, 36' and 'pin 29 and pin 15, 16, 21, 36'.Infinity ohms Go to Step 5Repair wiring harness to servo motor. --> End
3Check short circuit to groundMeasurement '3a': Ignition off Measure resistance between 'pins 1, 18, 29' of transfer box control unit plug and ground.Infinity ohms Go to Step 5Measurement '3b'
Measurement '3b': On servo motor, pull off sensor plug 'B' and servo motor plug 'A' Measure resistance between 'pins 1, 18, 29' of transfer box control unit plug and ground.Infinity ohms Go to Step 4Repair wiring harness to servo motor. --> End
4Replace transfer box servo motor> End
5Replace transfer box control unitSee note on replacing control units! --> End

DIAGNOSIS TROUBLESHOOTING PROCEDURE

Note. This fault code relates to the signal of potentiometer '2' (sensor 2) and potentiometer '1' (sensor 1) which, together with the temperature sensor, are integrated as a unit in the servo motor.

  1. Ignition on
  2. Internal transfer box control module function test

Note. Visual inspection: In the next troubleshooting section, please check first that the affected 'pins' of the transfer box control unit plug connection and the 'pins' of the plug connections on the servo motor are neither damaged nor corroded. Remove any soiling or corrosion/oxidation. Replace damaged parts/wires.

Note. Control unit replacement: Before replacing the 'transfer box control unit', the ground connections, power supply and plug connections on the control unit must be checked as OK. Please observe the coding of the control module. 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 'transfer box control unit' should be detected and remedied.

Work instructionDisplay OKIf not OK
1Check short circuit to B+Measurement '1a': Ignition off Pull plug off the transfer box control unit Ignition on Measure voltage between 'pins 12, 31' of transfer box control unit plug and ground.< 0.3 V go to measurement '1b'Repair wiring harness to servo motor. --> End
Measurement '1b': Ignition off Pull plugs 'A' and 'B' off servo motor Measure resistance between 'pins B5, B8 and pins A1, A2, A3, A4' of servo motor plugs 'A and B'. Measure resistance between 'pins B5 and B10, pin B4 and B8' of servo motor plug 'B'.Infinity ohms go to measurement '1c'Short circuit between servo motor leads. Go to Step 2
Measurement '1c': Measure resistance between 'pins 12, 31' and pins '1, 15, 16, 18, 21, 36' of transfer box control unit plug.Infinity ohms Go to Step 3Repair wiring harness to servo motor. --> End
2Replace transfer box servo motor> End
3Replace transfer box control moduleSee note on replacing control units! --> End

DIAGNOSIS TROUBLESHOOTING PROCEDURE

Work instructionDisplay OKIf not OK
1Check short circuit to groundMeasurement '1a': Ignition off Pull plug off transfer box control unit Measure resistance between 'pins 12 and 15, 16, 33, 44, 47 as well as between pins 31 and 2, 15, 16, 44, 47' of transfer box control unit plug.Infinity ohms Go to Step 2Go to measurement '1b'
Measurement '1b': Pull plugs 'A' and 'B' off servo motor Measure resistance between 'pins 12, 31 and pins 2, 15, 16, 33, 44, 47' of transfer box control unit plug.Infinity ohms Go to Step 3Repair wiring harness to servo motor. --> End
2Check open circuitMeasurement '2a': Pull plug 'B' off servo motor Measure resistance between 'pin B5' and 'pin B4' and 'pin B8' and 'pin B10' of servo motor plug 'B'.1.1 to 2.2 kohms go to measurement '2b'Go to Step 3
Measurement '2b': Measure resistance between 'pins 12 and B5' of transfer box control unit plug and 'pins 31 and B8' of removed sensor plug 'B'.< 5 ohms Go to Step 4Repair wiring harness to servo motor. --> End
3Replace transfer box servo motor> End
4Replace transfer box control moduleSee note on replacing control units! --> End

DIAGNOSIS TROUBLESHOOTING PROCEDURE

Troubleshooting for fault type: 'implausible signal'

Work instructionDisplay OKIf not OK
1Replace transfer box servo motor (potentiometer faulty)> End

DIAGNOSIS TROUBLESHOOTING PROCEDURE

  1. Ignition on
  2. Internal transfer box control module function test
  3. Engine running
  4. Selector lever position 'P'
  5. Engage longitudinal lock/gear reduction

Note. Visual inspection: In the next troubleshooting section, please check first that the affected 'pins' of the transfer box control unit plug connection and the 'pins' of the plug connections on the servo motor are neither damaged nor corroded. Remove any soiling or corrosion/oxidation. Replace damaged parts/wires.

Note. Control unit replacement: Before replacing the 'transfer box control unit', the ground connections, power supply and plug connections on the control unit must be checked as OK. Please observe the coding of the control module. 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 'transfer box control unit' should be detected and remedied.

Work instructionDisplay OKIf not OK
1Check short circuit to B+Measurement '1a': Ignition off Pull plug off the transfer box control unit Ignition on Measure voltage between 'pins 15, 16' of transfer box control unit plug and ground.< 0.3 V go to measurement '1b'Repair wiring harness to servo motor. --> End
Measurement '1b': Ignition off Connect plug to transfer box control unit Pull plug 'A' off servo motor Ignition on Measure voltage between 'pins A1, A4' of servo motor plug 'A' (wiring harness side) and ground.< 5 V Short circuit between servo motor leads. Go to Step 2Go to Step 3
2Replace transfer box servo motor> End
3Replace transfer box control moduleSee note on replacing control units! --> End

DIAGNOSIS TROUBLESHOOTING PROCEDURE

Troubleshooting fault type: 'short circuit to ground'

Work instructionDisplay OKIf not OK
1Check short circuit to groundMeasurement '1a': Ignition off Pull plug off transfer box control unit Measure resistance between 'pins 15, 16 and pins 2, 33, 36, 44, 47' of transfer box control unit plug.Infinity ohms Go to Step 3Go to measurement '1b'
Measurement '1b': Pull plugs 'A' and 'B' off servo motor Measure resistance between 'pins 15 and 16' and 'pins 15, 16 and pins 2, 33, 36, 44, 47' of transfer box control unit plug.Infinity ohms Go to Step 2Repair wiring harness to servo motor. --> End
2Replace transfer box servo motor> End
3Replace transfer box control moduleSee note on replacing control units! --> End

DIAGNOSIS TROUBLESHOOTING PROCEDURE

  1. Ignition on
  2. Internal transfer box control module function test
  3. Engine running
  4. Selector lever position 'P'
  5. Engage longitudinal lock/gear reduction

Note. Visual inspection: In the next troubleshooting section, please check first that the affected 'pins' of the transfer box control unit plug connection and the 'pins' of the plug connections on the servo motor are neither damaged nor corroded. Remove any soiling or corrosion/oxidation. Replace damaged parts/wires.

Note. Control unit replacement: Before replacing the 'transfer box control unit', the ground connections, power supply and plug connections on the control unit must be checked as OK. Please observe the coding of the control module. 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 'transfer box control unit' should be detected and remedied.

Work instructionDisplay OKIf not OK
1Check short circuit to B+Measurement '1a': Ignition off Pull plug off the transfer box control unit Ignition on Measure voltage between 'pins 15, 16' of transfer box control unit plug and ground.< 0.3 V go to measurement '1b'Repair wiring harness to servo motor. --> End
Measurement '1b': Ignition off Connect plug to transfer box control unit Pull plug 'A' off servo motor Ignition on Measure voltage between 'pins A1, A4' of servo motor plug 'A' (wiring harness side) and ground.< 5 V Short circuit between servo motor leads. Go to Step 2Go to Step 3
2Replace transfer box servo motor> End
3Replace transfer box control moduleSee note on replacing control units! --> End

DIAGNOSIS TROUBLESHOOTING PROCEDURE

Work instructionDisplay OKIf not OK
1Check short circuit to groundMeasurement '1a': Ignition off Pull plug off transfer box control unit Measure resistance between 'pins 15,16 and pins 2, 33, 36, 44, 47' of transfer box control unit plug.Infinity ohms Go to Step 2Go to measurement '1b'
Measurement '1b': Pull plugs 'A' and 'B' off servo motor Measure resistance between 'pins 15 and 16' and 'pins 15, 16 and pins 2, 33, 36, 44, 47' of transfer box control unit plug.Infinity ohms Go to Step 3Repair wiring harness to servo motor. --> End
2Replace transfer box servo motor> End
3Replace transfer box control moduleSee note on replacing control units! --> End

DIAGNOSIS TROUBLESHOOTING PROCEDURE

  1. Ignition on
  2. Internal transfer box control unit function test
  3. Engine running
  4. Selector lever position 'P'
  5. Engage longitudinal lock/gear reduction

Note. Visual inspection: In the next troubleshooting section, please check first that the affected 'pins' of the transfer box control unit plug connection and the 'pins' of the plug connections on the servo motor are neither damaged nor corroded. Remove any soiling or corrosion/oxidation. Replace damaged parts/wires.

Note. Control unit replacement: Before replacing the 'transfer box control unit', the ground connections, power supply and plug connections on the control unit must be checked as OK. Please observe the coding of the control unit. After the test drive, read out the fault memory again with the Porsche System Tester II No. 9588. Additional causes of faults that could damage the 'transfer box control unit' should be detected and remedied.

Work instructionDisplay OKIf not OK
1Check open circuitMeasurement '1a': Ignition off Pull plug 'A' off servo motor Measure resistance (servo motor winding) between 'pins A1 and A4' of servo motor plug 'A'.0.8 ohms go to measurement '1b'If infinity ohms then: Go to Step 2
Measurement Pull plug off transfer box control unit Measure resistance between 'pins 15, 16' of transfer box control unit plug and 'pins A1, A4' of removed lock plug 'A'.< 5 ohms Go to Step 3Repair wiring harness to servo motor. --> End
2Replace transfer box servo motor> End
3Replace transfer box control unitSee note on replacing control units! --> End

DIAGNOSIS TROUBLESHOOTING PROCEDURE

  1. Ignition on
  2. Internal transfer box control module function test

If short circuit to B+

Engage gear reduction.

If short circuit to ground

Do not engage gear reduction.

Note. Visual inspection: In the next troubleshooting section, please check first that the affected 'pins' of the transfer box control unit plug connection and the 'pins' of the plug connections on the servo motor are neither damaged nor corroded. Remove any soiling or corrosion/oxidation. Replace damaged parts/wires.

Note. Control unit replacement: Before replacing the 'transfer box control unit', the ground connections, power supply and plug connections on the control unit must be checked as OK. 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 'transfer box control unit' should be detected and remedied.

Work instructionDisplay OKIf not OK
1Check gear reduction LED activation line for short circuit to B+Measurement '1a': Switch off ignition Pull plug off transfer box control unit Pull plug off selector switch switch (running gear control module) Switch on ignition Measure voltage between 'pin 13' of selector switch plug (running gear control module) and ground.< 0.3 V go to measurement '1c'Go to measurement '1b'
Measurement '1b': Switch off ignition Pull plug off the transfer box control unit Switch on ignition Measure voltage between 'pin 4' of transfer box control unit plug and ground.< 0.3 V Go to Step 6Repair wiring. --> End
Measurement '1c': Switch off ignition Connect plug to selector switch (running gear control module) Pull plug off the transfer box control unit Switch on ignition Measure voltage between 'pin 4' of transfer box control unit plug and ground.< 0.3 V Go to Step 2Go to Step 5
2Check gear reduction LED activation line for short circuit to groundMeasurement '2a': Switch off ignition Measure voltage between 'pin 4' of transfer box control unit plug and battery positive.< 0.3 V go to measurement '2c'Go to measurement '2b'
Measurement '2b': Pull plug off selector switch switch (running gear control module) Measure resistance between 'pin 4' of transfer box control unit plug and ground.Infinity ohms Go to Step 5Repair wiring. --> End
Measurement '2c': Pull plug off selector switch switch (running gear control module) Measure voltage between 'pin 13' of selector switch plug (running gear control module) and battery positive.< 0.3 V Go to Step 3Go to Step 6
3Check for short circuit in the wiring to selector switch (running gear control module)Pull plug off selector switch switch (running gear control module) Pull plug off the transfer box control unit Measure resistance between 'pin 13' of selector switch plug (running gear control module) and 'pins: 3, 4, 6, 7, 8, 11, 12, 14, 15, 16'.Infinity ohms Go to Step 4Repair wiring. --> End
4Check gear reduction LED activation line for open circuitMeasure resistance between 'pin 13' of selector switch plug (running gear control module) and 'pin 4' of transfer box control unit.< 0.5 ohms Go to Step 6Repair wire. --> End
5Replace selector switch (running gear control module)> End
6Replace transfer box control moduleSee note on replacing control units! --> End

DIAGNOSIS TROUBLESHOOTING PROCEDURE

  1. Ignition on
  2. Internal transfer box control module function test

If short circuit to B+

Engage longitudinal lock.

If short circuit to ground

Do not engage longitudinal lock.

Note. Visual inspection: In the next troubleshooting section, please check first that the affected 'pins' of the transfer box control unit plug connection and the 'pins' of the plug connections on the servo motor are neither damaged nor corroded. Remove any soiling or corrosion/oxidation. Replace damaged parts/wires.

Note. Control unit replacement: Before replacing the 'transfer box control unit', the ground connections, power supply and plug connections on the control unit must be checked as OK. 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 'transfer box control unit' should be detected and remedied.

Work instructionDisplay OKIf not OK
1Check longitudinal lock LED activation line for short circuit to B+Measurement '1a': Switch off ignition Pull plug off selector switch switch (running gear control module) Pull plug off the transfer box control unit Switch on ignition Measure voltage between 'pin 14' of selector switch plug (running gear control module) and ground.< 0.3 V go to measurement '1c'Go to measurement '1b'
Measurement '1b': Switch off ignition Pull plug off the transfer box control unit Switch on ignition Measure voltage between 'pin 20' of transfer box control unit plug and ground.< 0.3 V Go to Step 6Repair wiring. --> End
Measurement '1c': Switch off ignition Connect plug to selector switch (running gear control module) Pull plug off the transfer box control unit Switch on ignition Measure voltage between 'pin 20' of transfer box control unit plug and ground.< 0.3 V Go to Step 2Go to Step 5
2Check longitudinal lock LED activation line for short circuit to groundMeasurement '2a': Switch off ignition Measure voltage between 'pin 20' of transfer box control unit plug and battery positive.< 0.3 V go to measurement '2c'Go to measurement '2b'
Measurement '2b': Pull plug off selector switch switch (running gear control module) Measure resistance between 'pin 20' of transfer box control unit plug and ground.Infinity ohms Go to Step 5Repair wiring. --> End
Measurement '2c': Pull plug off selector switch switch (running gear control module) Measure voltage between 'pin 14' of selector switch plug (running gear control module) and battery positive.< 0.3 V Go to Step 3Go to Step 6
3Check for short circuit in the wiring to selector switch (running gear control module)Pull plug off selector switch switch (running gear control module) Pull plug off the transfer box control unit Measure resistance between 'pin 14' of selector switch plug (running gear control module) and 'pins: 3, 4, 6, 7, 8, 11, 12, 13, 15, 16'.Infinity ohms Go to Step 4Repair wiring. --> End
4Check longitudinal lock LED activation line for open circuitMeasure resistance between 'pin 14' of selector switch plug (running gear control module) and 'pin 20' of transfer box control unit.< 0.5 ohms Go to Step 6Repair wiring. --> End
5Replace selector switch (running gear control module)> End
6Replace transfer box control moduleSee note on replacing control units! --> End

DIAGNOSIS TROUBLESHOOTING PROCEDURE

  1. Ignition on
  2. Internal transfer box control module function test

If short circuit to B+

Engage transverse lock.

If short circuit to ground

Do not engage transverse lock.

Note. Visual inspection: In the next troubleshooting section, please check first that the affected 'pins' of the transfer box control unit plug connection and the 'pins' of the plug connections on the servo motor are neither damaged nor corroded. Remove any soiling or corrosion/oxidation. Replace damaged parts/wires.

Note. Control unit replacement: Before replacing the 'transfer box control unit', the ground connections, power supply and plug connections on the control unit must be checked as OK. 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 'transfer box control unit' should be detected and remedied.

Work instructionDisplay OKIf not OK
1Check transverse lock LED activation line for short circuit to B+Measurement '1a': Switch off ignition Pull plug off selector switch switch (running gear control module) Pull plug off the transfer box control unit Switch on ignition Measure voltage between 'pin 6' of selector switch plug (running gear control module) and ground.< 0.3 V go to measurement '1c'Go to measurement '1b'
Measurement Switch off ignition Pull plug off the transfer box control unit Switch on ignition Measure voltage between 'pin 35' of transfer box control unit plug and ground.< 0.3 V Go to Step 6Repair wiring. --> End
Measurement '1c': Switch off ignition Connect plug to selector switch (running gear control module) Pull plug off the transfer box control unit Switch on ignition Measure voltage between 'pin 35' of transfer box control unit plug and ground.< 0.3 V Go to Step 2Go to Step 5
2Check transverse lock LED activation line for short circuit to groundMeasurement '2a': Switch off ignition Measure voltage between 'pin 35' of transfer box control unit plug and battery positive.< 0.3 V go to measurement '2c'Go to measurement '2b'
Measurement '2b': Pull plug off selector switch switch (running gear control module) Measure resistance between 'pin 35' of transfer box control unit plug and ground.Infinity ohms Go to Step 5Repair wiring. --> End
Measurement '2c': Connect plug to transfer box control unit Pull plug off selector switch switch (running gear control module) Measure voltage between 'pin 6' of selector switch plug (running gear control module) and battery positive.< 0.3 V Go to Step 3Go to Step 6
3Check for short circuit in the wiring to selector switch (running gear control module)Pull plug off selector switch switch (running gear control module) Pull plug off the transfer box control unit Measure resistance between 'pin 6' of selector switch plug (running gear control module) and 'pins: 3, 4, 7, 8, 11, 12, 13, 14, 15, 16'.Go to Step 4Repair wiring. --> End
4Check transverse lock LED activation line for open circuitMeasure resistance between 'pin 6' of selector switch plug (running gear control module) and 'pin 35' of transfer box control unit.< 0.5 ohms Go to Step 6Repair wiring. --> End
5Replace selector switch (running gear control module)> End
6Replace transfer box control moduleSee note on replacing control units! --> End

DIAGNOSIS TROUBLESHOOTING PROCEDURE

Note. After successful read out the fault memory must be erased and after satisfying the diagnostic conditions below must be read out again!

  1. Ignition on
  2. Internal transfer box control unit function test
  3. Vehicle stationary
  4. Engine running
  5. Brake actuated
  6. Selector lever position 'N'
  7. Via the left rocker switch on the 'selector switch (running gear control module)', alternately select the functions 'off-road driving program' and 'on-road driving program' (see Driver's Manual)
Work instructionDisplay OKIf not OK
1If the fault recurs after repeatedly erasing the fault memory, then: Repair/replace transfer box> End

DIAGNOSIS TROUBLESHOOTING PROCEDURE

  1. Ignition on
  2. Internal control module function test
Work instructionDisplay OKIf not OK
1Check software version of Tiptronic control module and correct it if necessary> End

DIAGNOSIS TROUBLESHOOTING PROCEDURE

  1. Ignition on
  2. Internal transfer box control unit function test
  3. Engine running
  4. Selector lever position 'P'
  5. Engage longitudinal lock

Note. Visual inspection: In the next troubleshooting section, please check first that the affected 'pins' of the transfer box control unit plug connection and the 'pins' of the plug connections on the servo motor are neither damaged nor corroded. Remove any soiling or corrosion/oxidation. Replace damaged parts/wires.

Note. Control unit replacement: Before replacing the 'transfer box control unit', the ground connections, power supply and plug connections on the control unit must be checked as OK. Please observe the coding of the control unit. After the test drive, read out the fault memory again with the Porsche System Tester II No. 9588. Additional causes of faults that could damage the 'transfer box control unit' should be detected and remedied.

Work instructionDisplay OKIf not OK
1Check fault memoryErase fault memory Check function of lock Read out fault memory againNo fault stored. --> EndGo to Step 2
2Replace servo motorErase fault memory Check function of lock Read out fault memory again> EndIf fault is not remedied by replacing the servo motor: Go to Step 3
3Replace control unitSee note on replacing control units! --> End

DIAGNOSIS TROUBLESHOOTING PROCEDURE

  1. Ignition on
  2. Internal control module function test

Note. If there is no incoming signal/message via the CAN drive using several control modules, the CAN drive must be checked for open or short circuits. Refer to ' CHECKING INSTRUCTIONS/CAN DATA BUS '.

Work instructionDisplay OKIf not OK
1CHECKING INSTRUCTIONS/CAN DATA BUS .> End
2Replace transfer box control moduleIf CAN drive check is OK: => End

DIAGNOSIS TROUBLESHOOTING PROCEDURE

  1. Ignition on
  2. Internal control module function test

Note. If there is no incoming signal/message via the CAN drive using several control modules, the CAN drive must be checked for open or short circuits. Refer to ' CHECKING INSTRUCTIONS/CAN DATA BUS '.

Work instructionDisplay OKIf not OK
1Read out fault memory for transverse lock control module (fault localisation)To eliminate further faults, please follow the diagnosis/troubleshooting instructions for the transverse lock control module, refer to the FINAL DRIVE, DIFFERENTIAL, DIFFERENTIAL LOCK article. . --> End
2CHECKING INSTRUCTIONS/CAN DATA BUS .> End

DIAGNOSIS TROUBLESHOOTING PROCEDURE

  1. Ignition on
  2. Internal transfer box control module function test
  3. Engine running
  4. Selector lever position 'P'
  5. Engage longitudinal lock/gear reduction

Note. Visual inspection: In the next troubleshooting section, please check first that the affected 'pins' of the transfer box control unit plug connection and the 'pins' of the plug connections on the servo motor are neither damaged nor corroded. Remove any soiling or corrosion/oxidation. Replace damaged parts/wires.

Note. Control unit replacement: Before replacing the 'transfer box control unit', the ground connections, power supply and plug connections on the control unit must be checked as OK. Please observe the coding of the control module. 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 'transfer box control unit' should be detected and remedied.

Work instructionDisplay OKIf not OK
1Check short circuit to B+Measurement '1a': Ignition off Pull plug off the transfer box control unit Ignition on Measure voltage between 'pin 21' of transfer box control unit plug and ground.< 0.3 V go to measurement '1b'Repair wiring harness to servo motor. --> End
Measurement '1b': Ignition off Connect plug to transfer box control unit Pull plug 'A' off servo motor Ignition on Measure voltage between 'pin A2' of servo motor plug 'A' (wiring harness side) and ground.< 0.5 V Short circuit between servo motor leads. Go to Step 2Go to Step 3
2Replace transfer box servo motor> End
3Replace transfer box control moduleSee note on replacing control units! --> End

DIAGNOSIS TROUBLESHOOTING PROCEDURE

Work instructionDisplay OKIf not OK
1Check short circuit to groundMeasurement '1a': Ignition off Pull plug off transfer box control unit Measure resistance between 'pin 21 and pins 2, 15, 16, 33, 44, 47' of transfer box control unit plug.Infinity ohms Go to Step 2Go to measurement '1b'
Measurement '1b': Pull plugs 'A' and 'B' off servo motor Measure resistance between 'pin 21 and pins 2, 15, 16, 33, 44, 47' of transfer box control unit plug.Infinity ohms Go to Step 3Repair wiring harness to servo motor. --> End
2Replace transfer box servo motor> End
3Replace transfer box control moduleSee note on replacing control units! --> End

DIAGNOSIS TROUBLESHOOTING PROCEDURE

  1. Ignition on
  2. Internal transfer box control unit function test
  3. Engine running
  4. Selector lever position 'P'
  5. Engage longitudinal lock/gear reduction

Note. Visual inspection: In the next troubleshooting section, please check first that the affected 'pins' of the transfer box control unit plug connection and the 'pins' of the plug connections on the servo motor are neither damaged nor corroded. Remove any soiling or corrosion/oxidation. Replace damaged parts/wires.

Note. Control unit replacement: Before replacing the 'transfer box control unit', the ground connections, power supply and plug connections on the control unit must be checked as OK. Please observe the coding of the control unit. After the test drive, read out the fault memory again with the Porsche System Tester II No. 9588. Additional causes of faults that could damage the 'transfer box control unit' should be detected and remedied.

Work instructionDisplay OKIf not OK
1Check short circuit to B+Measurement '1a': Ignition off Pull plug off transfer box control unit Ignition on Measure voltage between 'pin 36' of transfer box control unit plug and ground.< 0.3 V go to measurement '1b'Repair wiring harness to servo motor. --> End
Measurement Ignition off Connect plug to transfer box control unit Pull plug 'A' off servo motor Ignition on Measure voltage between 'pin A3' of servo motor plug 'A' (wiring harness side) and ground.< 0.3 V Short circuit between servo motor leads. Go to Step 2Go to Step 3
2Replace transfer box servo motor> End
3Replace transfer box control unitSee note on replacing control units! --> End

DIAGNOSIS TROUBLESHOOTING PROCEDURE

  1. Ignition on
  2. Internal transfer box control module function test

Note. Visual inspection: In the next troubleshooting section, please check first that the affected 'pins' of the transfer box control unit plug connection and the 'pins' of the plug connections on the servo motor are neither damaged nor corroded. Remove any soiling or corrosion/oxidation. Replace damaged parts/wires.

Note. Control unit replacement: Before replacing the 'transfer box control unit', the ground connections, power supply and plug connections on the control unit must be checked as OK. Please observe the coding of the control module. 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 'transfer box control unit' should be detected and remedied.

Troubleshooting fault type: 'Open circuit/short circuit to B+' and 'above upper limit'

Work instructionDisplay OKIf not OK
1Check voltage/ground supply of servo motor temperature sensorIgnition off Pull sensor plug 'B' off servo motor Ignition on Measure voltage between 'pins B6 and B7' of sensor plug 'B' (wiring harness side).Approx. 5 V Go to Step 2, measurement '2a'Measured voltage > 5 V Go to Step 2, measurement '2b' Measured voltage < 5 V Go to Step 3
2Check short circuit to B+/above upper limitMeasurement '2a': Ignition off Pull plug 'A' off servo motor Measure resistance on servo motor between: 'pins B6, B7 and pins A1, A2, A3, A4'.Infinity ohms Go to Step 3Short circuit between servo motor leads. Go to Step 4
Measurement '2b': Ignition off Pull plug 'A' off servo motor Pull plug off the transfer box control unit Ignition on Measure voltage between 'pins 29, 44' of transfer box control unit plug and ground.< 0.3 V Measurement '2c'Repair wiring harness to servo motor. --> End
Measurement '2c': Ignition off Measure resistance between 'pins 29, 44 and pins 15, 16, 21' of transfer box control unit plug.Infinity ohms Go to Step 5Repair wiring harness to servo motor. --> End
3Check open circuitMeasurement '3a': Measure resistance between 'pin B6' and 'pin B7' of servo motor plug 'B'.1.1 kohms at 21°C go to measurement '3b'Go to Step 4
Measurement '3b': Measure resistance between 'pins 29, 44' of transfer box control unit plug and 'pins B6, B7' of removed sensor plug 'B'.< 5 ohms Go to Step 5Repair wiring harness to servo motor. --> End
4Replace transfer box servo motor> End
5Replace transfer box control moduleSee note on replacing control units! --> End

DIAGNOSIS TROUBLESHOOTING PROCEDURE

Work instructionDisplay OKIf not OK
1Check short circuit to groundMeasurement '1a': Ignition off Pull plug off transfer box control unit Measure resistance between 'pin 29' of transfer box control unit plug and ground.Go to Step 3Measurement '1b'
Measurement On servo motor, pull off sensor plug 'B' and servo motor plug 'A' Measure resistance between 'pin 29' of transfer box control unit plug and ground.Infinity ohms Go to Step 2Repair wiring harness to servo motor. --> End
2Replace transfer box servo motor> End
3Replace transfer box control moduleSee note on replacing control units! --> End

DIAGNOSIS TROUBLESHOOTING PROCEDURE

  1. Ignition on
  2. Internal transfer box control module function test

Note. Visual inspection: In the next troubleshooting section, please check first that the affected 'pins' of the transfer box control unit plug connection and the 'pins' of the plug connections on the servo motor are neither damaged nor corroded. Remove any soiling or corrosion/oxidation. Replace damaged parts/wires.

Note. Control unit replacement: Before replacing the 'transfer box control unit', the ground connections, power supply and plug connections on the control unit must be checked as OK. Please observe the coding of the control module. 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 'transfer box control unit' should be detected and remedied.

Work instructionDisplay OKIf not OK
1Check voltage supply for servo motor temperature sensorIgnition off Pull sensor plug 'B' off servo motor Ignition on Measure voltage between 'pin B6 and ground' of sensor plug 'B' (wiring harness side).Approx. 5 V Go to Step 2, measurement '2a'Measured voltage > 5 V Go to Step 2, measurement '2b' Measured voltage < 5 V Go to Step 3
2Check short circuit to B+Measurement '2a': Ignition off Pull plug 'A' off servo motor Measure resistance on servo motor between: 'pins B6 and pins A1, A2, A3, A4'.Infinity ohms Measurement '2b'Short circuit between servo motor leads. Go to Step 4
Measurement '2b': Ignition off Pull plug 'A' off servo motor Pull plug off the transfer box control unit Ignition on Measure voltage between 'pin 29' of transfer box control unit plug and ground.< 0.3 V Measurement '2c'Repair wiring harness to servo motor. --> End
Measurement '2c': Ignition off Measure resistance between 'pin 29 and pins 15,16, 21, 36' of transfer box control unit plug.Infinity ohms Go to Step 5Repair wiring harness to servo motor. --> End
3Check short circuit to groundMeasurement '3a': Ignition off Measure resistance between 'pin 29' of transfer box control unit plug and ground.Infinity ohms Go to Step 5Measurement '3b'
Measurement '3b': On servo motor, pull off sensor plug 'B' and servo motor plug 'A' Measure resistance between 'pin 29' of transfer box control unit plug and ground.Infinity ohms Go to Step 4Repair wiring harness to servo motor. --> End
4Replace transfer box servo motor> End
5Replace transfer box control moduleSee note on replacing control units! --> End

DIAGNOSIS TROUBLESHOOTING PROCEDURE

  1. Ignition on
  2. Internal transfer box control unit function test

Note. Visual inspection: In the next troubleshooting section, please check first that the affected 'pins' of the transfer box control unit plug connection and the 'pins' of the plug connections on the servo motor are neither damaged nor corroded. Remove any soiling or corrosion/oxidation. Replace damaged parts/wires.

Note. Control unit replacement: Before replacing the 'transfer box control unit', the ground connections, power supply and plug connections on the control unit must be checked as OK. Please observe the coding of the control unit. After the test drive, read out the fault memory again with the Porsche System Tester II No. 9588. Additional causes of faults that could damage the 'transfer box control unit' should be detected and remedied.

Work instructionDisplay OKIf not OK
1Check fault memoryErase fault memory Check function of lock Read out fault memory againIf only fault '2373' stored. Go to Step 2If, additionally, fault codes 2057 or 2058 stored, then diagnose/troubleshoot these codes. --> End
2Replace control unitSee note on replacing control units! --> End

DIAGNOSIS TROUBLESHOOTING PROCEDURE

  1. Ignition on
  2. Internal transfer box control module function test
  3. Engine running
  4. Selector lever position 'P'
  5. Engage longitudinal lock/gear reduction

Note. Visual inspection: In the next troubleshooting section, please check first that the affected 'pins' of the transfer box control unit plug connection and the 'pins' of the plug connections on the servo motor are neither damaged nor corroded. Remove any soiling or corrosion/oxidation. Replace damaged parts/wires.

Note. Control unit replacement: Before replacing the 'transfer box control unit', the ground connections, power supply and plug connections on the control unit must be checked as OK. Please observe the coding of the control module. 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 'transfer box control unit' should be detected and remedied.

Troubleshooting fault type: 'electrical fault in electric circuit'

Work instructionDisplay OKIf not OK
1Check short circuit to B+Measurement '1a': Ignition off Pull plug off the transfer box control unit Ignition on Measure voltage between 'pins 21, 36' of transfer box control unit plug and ground.< 0.3 V go to measurement '1b'Repair wiring harness to servo motor. --> End
Measurement '1b': Ignition off Connect plug to transfer box control unit Pull plug 'A' off servo motor Ignition on Gear reduction/longitudinal lock not engaged Measure voltage between 'pins A2, A3' of servo motor plug 'A' (wiring harness side) and ground.< 0.3 V Go to Step 2Go to Step 5
2Check short circuit to groundMeasurement '2a': Ignition off Pull plug off transfer box control unit Ignition off Measure voltage between 'pin A2' of transfer box servo motor plug 'A' (wiring harness side) and battery positive.< 0.3 V go to measurement '2c'Go to measurement '2b'
Measurement '2b': Pull plug off transfer box control unit Measure resistance between 'pin 21 and pins 2, 15, 16, 33, 44, 47' of transfer box control unit plug.Infinity ohms Go to Step 5Repair wiring harness to servo motor. --> End
Measurement '2c': Measure resistance between 'pin A2 and ground' of servo motor plug 'A'.Go to Step 3Go to Step 4
3Check open circuit/winding short circuitMeasurement '3a': Measure resistance between 'pins A2 and A3' of servo motor plug 'A'.Approx. 20 ohms go to measurement '3b'Go to Step 4
Measurement '3b': Pull plug off the transfer box control unit Measure resistance between 'pins 21, 36' of transfer box control unit plug and 'pins A2, A3' of servo motor plug 'A' (wiring harness side).< 5 ohms Go to Step 5Repair wiring harness to servo motor. --> End
4Replace transfer box servo motor> End
5Replace transfer box control moduleSee note on replacing control units! --> End

DIAGNOSIS TROUBLESHOOTING PROCEDURE

Work instructionDisplay OKIf not OK
1Check short circuit to groundMeasurement '1a': Ignition off Pull plug off transfer box control unit Measure resistance between 'pins 21, 36 and pins 2, 15, 16, 33, 44, 47' of transfer box control unit plug.Infinity ohms Go to Step 2Go to measurement '1b'
Measurement '1b': Pull plugs 'A' and 'B' off servo motor Measure resistance between 'pins 21, 36 and pins 2, 15, 16, 33, 44, 47' of transfer box control unit plug.Infinity ohms Go to Step 3Repair wiring harness to servo motor. --> End
2Check open circuitMeasurement '2a': Pull plug 'A' off servo motor Measure resistance between 'pin A2' and 'pin A3' of servo motor plug 'A'.Approx. 20 ohms go to measurement '2b'Go to Step 3
Measurement '2b': Measure resistance between 'pins 21, 36' of transfer box control unit plug and 'pins A2, A3' of removed servo motor plug 'A' (wiring harness side).< 5 ohms Go to Step 4Repair wiring harness to servo motor. --> End
3Replace transfer box servo motor> End
4Replace transfer box control moduleSee note on replacing control units! --> End

DIAGNOSIS TROUBLESHOOTING PROCEDURE

  1. Ignition on
  2. Internal transfer box control unit function test
  3. Vehicle stationary
  4. Engine running
  5. Brake actuated
  6. Selector lever position 'N'
  7. Via the left rocker switch on the 'selector switch (running gear control module)', alternately select the functions LOW RANGE and longitudinal lock LOW RANGE 100% (see Driver's Manual)
Work instructionDisplay OKIf not OK
1If the fault recurs after repeatedly erasing the fault memory, then: Repair/replace transfer box> End

DIAGNOSIS TROUBLESHOOTING PROCEDURE

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