1998 VOLKSWAGEN JETTA sensor

Downloaded from www.Manualslib.com manuals search engine 01-257



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

Downloaded from www.Manualslib.com manuals search engine 01-258


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

Downloaded from www.Manualslib.com manuals search engine 01-259



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

Downloaded from www.Manualslib.com manuals search engine 01-264


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

Downloaded from www.Manualslib.com manuals search engine 01-265


Display group number 0691) is required to
perform a zero compensation of longitudinal
acceleration sensor -G251- Page 01
-281 .
Display group number 0932) is required to
perform a driving test Page 01
-284. It serves
to check the plausibility of the signals from the
steering angle sensor -G85-, Sensor for
transverse acceleration -G200- Sender for
Rotation Rate -G202- and sender 1 for brake
booster -G201-.
When the ABS control module (w/EDL) -J104- is
replaced, a zero compensation must be
performed for the following components:

Sensor for transverse acceleration -G200-.

Steering angle sensor -G85-.

Sender 1 for brake booster -G201-.

Longitudinal acceleration sensor -G251-.1)
When the individual sensors or sensors are
changed, a zero compensation must only be
carried out for the changed component.

1) For 4MOTION vehicles only

2) For ABS/EDL/ASR/ESP and
ABS/EDL/ASR/ESP 4MOTION only
Стр. 107из 129 On Board Diagnostic (OBD), performing

Downloaded from www.Manualslib.com manuals search engine 01-269



Display group number 40: switching off
longitudinal acceleration sensor -G251-

All functions which could previously be
performed with V.A.G 1551 can now also be
carried out with the tester VAS 5051.

Display group 040 is necessary for shutting off
longitudinal acceleration sensor -G251- in order
to utilize the maximum engine performance for
a test, e.g. on a rolling road test bed. In
addition, the all wheel drive is shut off and the
vehicle behaves like a front wheel drive vehicle.

Switch ignition off and on again to reactivate the
longitudinal acceleration sensor -G251-.

- Connect V.A.G 1551 scan tool and select
(address word 03) brake electronics control
module with ignition switched on; Page 01
-
163 .
Стр. 111из 129 On Board Diagnostic (OBD), performing

Downloaded from www.Manualslib.com manuals search engine 01-270


Rapid data transfer HELP
Enter address word XX Indicated on display:
- Press keys 0 and 4. (The function
"Initiating basic setting" is selected with
04).
Rapid data transfer Q
04 - Basic settin
g
Indicated on display:
- Confirm entry with key Q.
Basic setting HELP
Enter displa
y group number XXX
Indicated on display:
- Press keys 0, 4 and 0
- Confirm entry with key Q.
ABS warning light flashes.
Basic setting 40 Indicated on display:
- The longitudinal acceleration sensor -
G251- is now switched off.
- After completing the checks, reactivate
the longitudinal acceleration sensor -
G251- by switching the ignition off and
on again, once.
Стр. 112из 129 On Board Diagnostic (OBD), performing

Downloaded from www.Manualslib.com manuals search engine 01-271



Display group number 60: zero compensation
of steering angle sensor -G85-

Note:

All functions which could previously be
performed with V.A.G 1551 can now also be
carried out with the tester VAS 5051.

- Connect V.A.G 1551 scan tool and select
(address word 03) brake electronics control
module with ignition switched on; Page 01
-
163 .

- Start engine.

- Carry out a short test drive over a flat and level
surface. Drive straight-ahead and not faster then
20 km/h (12.5 mph) and observe the following
points:

If the steering wheel is not in the centered
position when driving straight ahead, the
steering must be corrected within the
framework of an alignment check.
Repair Manual, Suspension, Wheels,
Steering, Repair Group 44; Vehicle alignment.
Стр. 113из 129 On Board Diagnostic (OBD), performing