Fault overview

21 No route guidance 91 - D 22

3 22 No route guidance 91 - D 23

4 23 No DSP functions 91 - D 23

5 24 Inaccurate position determination 91 - D 24

6 25 Reversing is not recognised 91 - D 24

7 26 No satellite reception 91 - D 25

9 28 No outside-temperature display 91 - D 26

12 31 No function 91 - D 27

14 33 No route guidance 91 - D 28

15 34 No route guidance 91 - D 28

16 35 No audio functions 91 - D 29

17 36 No telephone function 91 - D 29

18 37 No telephone function 91 - D 29

91 01 Diagnosis/troubleshooting, PCM 91 - D19

Printed in Germany - 17, 1997 98691D1

Test point

Fault code

Fault effect

Page

20 21

No screen display

Fault, fault code

Possible causes, elimination, notes

Test point 1

Data lead, air conditioner

Open circuit/short to

Signal disturbance Fault code 20

Open circuit/short to ground

1. Pull off plug II on the display and operator control unit.

2. Pull off plug C on the heater/A/C control unit.

3. Check lead from plug II pin 15 to plug C 12 for continuity and short

Note

The lead is routed via the 10-pole plug connection on the Short to B+

1. Pull off plug II on the display and operator control unit.

2. Pull off plug C on the heater/A/C control unit.

3. Check lead from plug II pin 15 to plug C 12 for short to B+.

Signal disturbance

Check wiring harness for short with other leads.

Fault, fault code

Possible causes, elimination, notes

Test point 2

Data lead, navigation

Open circuit/short to

Signal disturbance Fault code 21

Open circuit/short to ground

1. Pull off plug II on the display and operator control unit.

2. Pull off plug on the navigation unit.

3. Check lead from navigation unit plug pin 7 to plug II pin 17 for

Short to B+

1. Pull off plug II on the display and operator control unit.

2. Pull off plug on the navigation unit.

3. Check lead from navigation unit plug pin 7 to plug II pin 17 for

Signal disturbance

Check lead from navigation unit plug pin 7 to plug II pin 17 for

Fault, fault code

Test point 3

PCM-navigation unit Short to ground

Fault code 22

1. Pull off plug II on the display and operator control unit.

2. Pull off plug on the navigation unit.

3. Check lead from navigation unit plug pin 5 to plug II pin 4

Short to B+

1. Pull off plug II on the display and operator control unit.

2. Pull off plug on the navigation unit.

3. Check lead from navigation unit plug pin 5 to plug II pin 4

Test point 4

Data lead, DSP-PCM Open circuit/short to

Signal disturbance Fault code 23

Open circuit/short to ground

1. Pull off plug II on the display and operator control unit.

2. Pull off plug I (18-pole) on the amplifier.

3. Check lead from plug II pin 14 to plug I pin 17 for continuity and short to ground.

Short to B+

1. Pull off plug II on the display and operator control unit.

2. Pull off plug I (18-pole) on the amplifier.

3. Check lead from plug II pin 14 to plug I pin 17

Fault, fault code Possible causes, elimination, notes

Signal disturbance

Check lead from plug II pin 14 to plug I pin 17 for short

Test point 5

Speedometer A, navigation unit Open circuit/short to ground/short to B+ Fault code 24

Open circuit/short to ground/short to B+

1. Pull off plug on the navigation unit.

2. Pull off plug I on the instrument cluster.

3. Check lead from navigation unit plug pin 3 to plug I pin 13 for continuity and short to ground or short to B+.

Note

The lead is routed via jumper plug 1 on relay carrier 1

Test point 6

Signal, reverse gear-navigation unit Signal implausible Fault code 25

L Check reversing light switch or, on Tiptronic vehicles, position switch.

2. Check lead from navigation unit plug pin 4 to the reversing light switch or position switch for short circuit to B+.

Note

The lead is routed via plug connection X 2/1 and via the jumper

Fault, fault code

Possible causes, elimination, notes

Test point 7

Antenna, navigation unit

Fault code 26

1. Check whether plug connection of the antenna lead is

2. Check whether plug connection of the antenna lead on the

3. Check continuity of the antenna lead.

Test point 8

PCM-instrument cluster Short to ground

Fault code 27

Short to ground

1. Pull off plug I on the display and operator control unit.

2. Pull off plug III on the instrument cluster.

3. Check lead from plug I pin 20 to plug III pin 6 for short to ground. Short to B+

1. Pull off plug I on the display and operator control unit.

2. Pull off plug III on the instrument cluster.

3. Check lead from plug I pin 20 to plug III pin 6 for short B+.

Fault, fault code

Possible causes, elimination, notes

Test point 9

Data lead, instrument

Open circuit/short to B+ Short to ground Signal disturbance Fault code 28

1. Pull off plug I on the display and operator control unit.

2. Pull off plug III on the instrument cluster

3. Check lead from plug I pin 21 to plug III pin 11 for continuity and

Short to ground

1. Pull off plug I on the display and operator control unit.

2. Pull off plug III on the instrument cluster

3. Check lead from plug I pin 21 to plug III pin 11 for short to ground, Signal disturbance

Check lead from plug I pin 21 to plug III pin 11 for short with other

Test point 10

Vehicle data record Programming error Fault code 29

1. Select menu item Modify coding,

2. Select Vehicle model.

3. Modify coding from LHD vehicle (RHD vehicle) to RHD vehicle (LHD vehicle).

4. Modify coding from RHD vehicle (LHD vehicle) to LHD vehicle (RHD vehicle).

If the fault appears again, replace the display and operator control unit.

Fault, fault code

Possible causes, elimination, notes

Test point 11

Program memory erre

Fault code 30

error

1. Remove CD from navigation unit.

2. Switch off PCM.

3. Switch on PCM and insert CD.

4. Clear fault memory.

5. Read out fault memory

If the fault appears again, insert a different CD (older version).

6. Switch off PCM.

7. Switch on PCM.

8. Clear fault memory.

9. Read out fault memory

If the fault appears again, replace the display and operator control unit.

This fault is stored only if the vehicle is driven faster than 50 km/h for more than 10 seconds.

2. Pull off plug II on the display and operator control unit.

3. Connect voltmeter to plug II pin 2 (positive) and ground Switch on ignition. Display: Battery voltage.

Test point 12

Signal] terminal 15 PCM Note

Open circuit Thjs 1

Fault code 31 cn

Fault, fault code

Possible causes, elimination, notes

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