1998 VOLKSWAGEN JETTA Service Manual

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Checking longitudinal acceleration
sensor -G251-
1)

Display group number 006

- Press keys 0, 0 and 6

- Confirm entry with key Q.
Read measured value block
6
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
6
0.0m/s2
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.
1) For 4MOTION vehicles only
Стр. 99из 129 On Board Diagnostic (OBD), performing

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Read measured value block
6 Display group number: 006
0.0m/s
2

Indicated on display (example)

Vacant

Vacant

Vacant

Longitudinal acceleration sensor:
1)

Specification when vehicle is stationary:+/- 1.5m/s2

Specification when accelerating forwards: The values increase steadily.

Specification when accelerating in reverse: The values increase steadily
with a negative sign (-).

Check longitudinal acceleration sensor -G251- Page 01-259
Perform electrical check Page 01-288
1) When performing a test drive where the V.A.G 1551 scan tool or tester VAS 5051 is
connected and in diagnosis or read measured value block mode there is no ABS regulation.
The ABS warning light does not light up. The OBD of ABS control module (w/EDL) -J104- is
terminated when exceeding a speed of 20 km/h (13 mph).
Стр. 100из 129 On Board Diagnostic (OBD), performing

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Checking longitudinal acceleration sensor -
G251-
1)

- Remove longitudinal acceleration sensor -G251-
without pulling off connector.
Repair Manual, Brake System, Repair Group
45

Note:
All functions that have so far been carried out
with V.A.G 1551 can now also be carried out with
the tester VAS 5051.

- Connect V.A.G. 1551 scan tool.
The longitudinal acceleration sensor -G251- can
be checked with the help of function "Read
measured value block", display group 006.
Read measured value block
6
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
6
0.0m/s2
Indicated on display: e.g. (vehicle stationary)
1) For 4MOTION vehicles only
Стр. 101из 129 On Board Diagnostic (OBD), performing

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A positive sign corresponds to the force
when driving forward. -
Turn 90 to right of installation position
(see illustration).
- Display in display zone 1 (with vehicle
stationary) e.g. +9.8 1 m/s
2.

A negative sign corresponds to the force
when driving backward. -
Turn 90 to left of installation position
(see illustration).
- Display in display zone 1 (with vehicle
stationary) e.g. -9.8 1 m/s
2.
Стр. 102из 129 On Board Diagnostic (OBD), performing

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Checking data bus wiring

Display group number 125

- Press keys 1, 2 and 5

- Confirm entry with key Q.
Read measured value block
125
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 125
Engine 1 St.ang. 1 4WD 1 Gear.1
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. 103из 129 On Board Diagnostic (OBD), performing

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Read measured value block
125 Display group number: 125
Engine
1 St.ang.
1 4WD
1 Gear.
1 Indicated on display (example)

Data Bus for transmission1)
1 Data bus connection is available.
0 Data bus connection is not available.3)

Data bus for all-wheel drive2)

1 Data bus connection is available.
0 Data bus connection is not available.3)

Data bus for steering angle

1 Data bus connection is available.
0 Data bus connection is not available.3)

Data bus for engine

1 Data bus connection is available.
0 Data bus connection is not available.3)
1) Vehicles with automatic transmission only.

Incorrect transmission control module or incorrect transmission control module coding.

Transmission control module malfunction.
Repair Manual, Transmission, Repair Group 01 for relevant transmission code.
2) For 4MOTION vehicles only
3) Data bus connection is interrupted or data bus wires are interchanged.
Electrical Wiring Diagrams, Troubleshooting & Component Locations binder.
Стр. 104из 129 On Board Diagnostic (OBD), performing

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Output Diagnosic Test Mode (DTM)
Page 01
-74
Стр. 105из 129 On Board Diagnostic (OBD), performing

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Basic setting, initiating
Function 04 "Initiate basic setting" performs
several functions with ABS Mark 60:

Display group number 001 is required only to
bleed the hydraulic system Page 01
-266

Note:
The basic setting is only necessary to bleed the
hydraulic unit if at least one chamber of the brake
fluid reservoir has completely run dry.

Display group number 0401) is required to shut
off the longitudinal acceleration sensor -G251-
in order to utilize the maximum engine
performance for a test, e.g. on a rolling road
test stand Page 01
-269 .
Display group number 0602) is required to
perform a zero compensation for steering angle
sensor -G85- Page 01
-271 . Subsequently a
test drive must be performed Page 01
-284 .
Display group number 0632) is required to
perform a zero compensation for sensor for
transverse acceleration -G200- Page 01
-
275 . Subsequently a test drive must be
performed Page 01
-284 .
Display group number 0662) is required to
perform a zero compensation for Sender 1 for
brake booster -G201- Page 01
-278 .
Subsequently a test drive must be performed
Page 01
-284 .
Стр. 106из 129 On Board Diagnostic (OBD), performing