1998 VOLKSWAGEN JETTA Service Manual

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- Connect V.A.G 1551 scan tool and select
(address word 03) brake electronics control
module with ignition switched on; Page 01
-
163 .
Rapid data transfer HELP
Select function XX Indicated on display:
- Press keys 0 and 8. (The function "Read
measured value block" is initiated with 08.)
Rapid data transfer Q
08 - Read measured value block Indicated on display:
- Confirm entry with key Q.
Read measured value block
Enter displa
y group number XXX
Indicated on display:
- Enter display group number. List of selectable
display group numbers Page 01
-242 .
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Overview of selectable display group numbers
Display group number
Display zone
Designation
001 1 Wheel speed at left front wheel sensor (km/h)
2 Wheel speed at right front wheel sensor (km/h)
3 Wheel speed at left rear speed sensor (km/h)
4 Wheel speed at right rear speed sensor (km/h)
002 1 Wheel speed at left front speed sensor (km/h)
2 Wheel speed at right front wheel sensor (km/h)
3 Wheel speed at left rear speed sensor (km/h)
4 Wheel speed at right rear speed sensor (km/h)
003 1 Brake light switch
2 Brake system warning light
3 ABS warning light
4 ASR/ESP warning light
Стр. 84из 129 On Board Diagnostic (OBD), performing

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Display group number
Display zone
Designation
004 1 Steering angle sensor
2 Lateral accelerator sensor
3 Sender for rotation rate
4 Vacant
005 1 Brake pressure sensor
2 Vacant
3 Vacant
4 Vacant
Стр. 85из 129 On Board Diagnostic (OBD), performing

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Display group number
Display zone
Designation
006 1
Longitudinal acceleration sensor
1)
2 Vacant
3 Vacant
4 Vacant
125 1 Data bus for engine
2
Data bus for steering angle
2)
3
Data bus for all-wheel drive
1)
4
Data bus for transmission
3)
1) 4MOTION vehicles only
2) ABS/EDL/ASR/ESP and ABS/EDL/ASR/ESP 4MOTION
3) Vehicles with automatic transmission only
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Test sequence and test tables with
measured values

Checking speed sensor allocation

Display group number 001

- Press keys 0, 0 and 1.

- Confirm entry with key Q.
Read measured value block
1
1 2 3 4
- There are always 4 display zones -
arrows- in the measured value block.
Decoding the individual values in display
zones 1 to 4 can be read-off from the
following tables.
Read measured value block 1
0 km/h 0 km/h 0 km/h 0 km/h
Indicated on display: (vehicle stationary)
Press C key for the next display group
number entry.
If the key is pressed, keys 0 and 8 for
work sequence "Read measured value
block" must be pressed again afterwards to
regain entry.
Стр. 87из 129 On Board Diagnostic (OBD), performing

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Note:
For display group number 001 remember:
The actual wheel speeds are displayed. They serve to check the speed sensor allocation to the
wheel. (The vehicle must be raised and the wheel must be rotated by hand by a 2nd mechanic).
Read measured value block
1 Display group number: 001
0 km/h 4 km/h 0 km/h 0 km/h
Indicated on display: (Example)

Wheel speed at right rear speed sensor
(0...255 km/h)

Wheel speed at left rear speed sensor

(0...255 km/h)

Wheel speed at right front speed sensor
(0...255 km/h)

Wheel speed at left front speed sensor

(0...255 km/h)
Стр. 88из 129 On Board Diagnostic (OBD), performing

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Checking speed sensor

Display group number 002

- Press keys 0, 0 and 2.

- Confirm entry with key Q.
Read measured value block
2
1 2 3 4
- There are always 4 display zones -
arrows- in the measured value block.
Decoding the individual values in display
zones 1 to 4 can be read-off from the
following tables.
Read measured value block
2
255 km/h 255 km/h 255 km/h 255 km/h
Indicated on display: (vehicle stationary)
Press C key for the next display group
number entry.
If the key is pressed, keys 0 and 8 for
work sequence "Read measured value
block" must be pressed again afterwards to
regain entry.
Стр. 89из 129 On Board Diagnostic (OBD), performing

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Note:
For display group number 002 remember:
The reading of measured value blocks in display group number 002 must be undertaken when
driving off slowly. Then the ABS Control Module (w/EDL) -J104- will store the first usable
voltage signals provided by the speed sensors and display these as a fixed value in the
measured value block.
Read measured value block
2 Display group number: 002
3 km/h
1)
6 km/h1)
2 km/h2)
1 km/h2)
Indicated on display: (when driving off slowly)

Wheel speed at right rear speed sensor
(0...255 km/h)

Wheel speed at left rear speed sensor

(0...255 km/h)

Wheel speed at right front speed sensor
(0...255 km/h)

Wheel speed at left front speed sensor

(0...255 km/h)
1) If the deviations in display zones 1 and 2 are greater than 6 km/h (approx. 3.75 mph), the
following faults may be present:
2) If the deviations in display zones 3 and 4 are greater than 2 km/h (approx. 1.25 mph), the
following faults may be present:
Note:

Air gap between speed sensor and rotor may be too big.
- Check that speed sensor is screwed correctly to wheel bearing housing.

Speed sensor or rotor exterior damaged.
- Change damaged component.
Стр. 90из 129 On Board Diagnostic (OBD), performing