Audi Workshop Service and Repair Manuals > A2 > Running gear self-diagnosis for ESP, steering | Self diagnosis, V.A.G Inspection Service | Performing self-diagnosis

Final control diagnosis > < Checking of brake pressure solenoid valve, in brake servo -N247

Running gear self-diagnosis for ESP, steering

Performing self-diagnosis

Reading measured value block

The control unit can output a wide range of measured values. These measured values supply information on the operating status of the system/connected senders. In many cases, the measured values output can be used to assist with fault-finding and fault rectification. As the measured values cannot all be output at the same time, they are summarised in individual display groups which can be selected by way of display group numbers.

There is no ABS/ESP/EBPD control in the course of a test drive with the fault reader V.A.G 1551 connected up and set to diagnosis/measured value block mode. The ABS warning lamp flashes; the ASR/ESP lamp lights.

‒ Connect up fault reader V.A.G 1551, enter address word 03 "Brake electronics" and keep switching until "Select function XX" appears on display.

→ Indicated on display:

Rapid data transfer HELP

Select function XX

‒ Press keys 0 and 8 to start "Reading measured value block" function.

→ Indicated on display:

Rapid data transfer Q

08 - Reading measured value block

‒ Confirm entry with Q key.

→ Indicated on display:

Reading measured value block

Enter display group number XXX

‒ Enter display group number, list of available display group numbers =>Page 01-87.

List of available display group numbers


Display group number	Display zone	Designation
001	1	Wheel speed at front left speed sensor (km/h)
	2	Wheel speed at front right speed sensor (km/h)
	3	Wheel speed at rear left speed sensor (km/h)
	4	Wheel speed at rear right speed sensor (km/h)
002	1	Starting speed at front left speed sensor (km/h)
	2	Starting speed at front right speed sensor (km/h)
	3	Starting speed at rear left speed sensor (km/h)
	4	Starting speed at rear right speed sensor (km/h)
003	1	Brake light switch
	2	Brake detection switch
	3	Not used
	4	Not used

004	1	Steering angle sender
	2	Lateral acceleration sender
	3	Yaw rate sender
	4	Not used
005	1	Brake pressure sender
	2	Brake pressure sender
	3	Not used
	4	Not used
125	1	Engine data bus
	2	Steering angle data bus 2)
	3	Not used
	4	Gearbox data bus 1)

1) Vehicles with automatic gearbox only

Test sequence and test tables with measured values

Display group number 001

‒ Press keys 0, 0 and 1.
‒ Confirm entry with Q key.

→ A measured value block always has 4 display zones -arrows-. Explanatory notes on values 1 - 4 in the individual display zones are given in the following test table.

Reading measured value block 1 ⇒

⇒ 1 ⇒ 2 ⇒ 3 ⇒ 4

→ Indicated on display (with vehicle stationary):

Reading measured value block 1⇒

0 km/h 0 km/h 0 km/h 0 km/h

The next display group number 002 can be selected by pressing key -3-.

Press C key to enter next display group number.

If ⇒key is pressed, keys 0 and 8 then have to be pressed to return to "Reading measured value block" sequence.

Heed the following for display group number 001:

The instantaneous wheel speeds are displayed. They are used to check the speed sensors and speed sensor wheel assignment (this involves raising the vehicle and having a second mechanic turn the wheel by hand).

Reading measured value block			1 ⇒	Display group number: 001
0 km/h	0 km/h	0 km/h	0 km/h	◂ Indicated on display (example)
				Wheel speed at rear right speed sensor - (0...255 km/h)
			Wheel speed at rear left speed sensor - (0...255 km/h)
		Wheel speed at front right speed sensor - (0...255 km/h)
	Wheel speed at front left speed sensor - (0...255 km/h)

Display group number 002

‒ Press keys 0, 0 and 2.
‒ Confirm entry with Q key.

→ A measured value block always has 4 display zones -arrows-. Explanatory notes on values 1 - 4 in the individual display zones are given in the following test table.

Reading measured value block 2 ⇒

⇒ 1 ⇒ 2 ⇒ 3 ⇒ 4

→ Indicated on display (with vehicle stationary):

Reading measured value block 2⇒

255 km/h 255 km/h 255km/h 255 km/h

The next display group number down/up can be consecutively selected by pressing key -1- or key -3- respectively.

Press C key to enter next display group number.

If ⇒key is pressed, keys 0 and 8 then have to be pressed to return to "Reading measured value block" sequence.

Reading measured value block			2 ⇒	Display group number: 002
3 km/h1)	6 km/h1)	2 km/h1)	1 km/h1)	◂ Indicated on display (on driving off slowly)
				Starting speed at rear right speed sensor - (0...255 km/h)
			Starting speed at rear left speed sensor - (0...255 km/h)
		Starting speed at front right speed sensor - (0...255 km/h)
	Starting speed at front left speed sensor - (0...255 km/h)

Output of wheel speed at which signal is first detected

Output: Front left, front right, rear left, rear right

Value of 255 indicates that measurement has not yet been taken

Display group number 003

‒ Press keys 0, 0 and 3.
‒ Confirm entry with Q key.

→ A measured value block always has 4 display zones -arrows-. Explanatory notes on values 1 - 4 in the individual display zones are given in the following test table.

Reading measured value block 3 ⇒

⇒ 1 ⇒ 2 ⇒ 3 ⇒ 4

→ Indicated on display (with vehicle stationary):

Reading measured value block 3⇒

not pressed not pressed

The next display group number down/up can be consecutively selected by pressing key -1- or key -3- respectively.

Press C key to enter next display group number.

If ⇒key is pressed, keys 0 and 8 then have to be pressed to return to "Reading measured value block" sequence.

Reading measured value block			3 ⇒	Display group number: 003
Not pressed	Not pressed			◂ Indicated on display
				Not used
			Not used
		Brake detection switch: - Not pressed ⇒Brake pedal not pressed - Pressed ⇒Brake pedal pressed In the event of deviations: Test step no. 19, Page 01-146
	Brake light switch: - 0 ⇒Brake pedal not pressed - 1 ⇒Brake pedal pressed If V.A.G 1551 displays -0- with foot brake pressed or -1- with foot brake not pressed, perform test step no. 4 on Page 01-122 It is also possible that the brake light switch has not been correctly adjusted =>Adjusting brake light switch =>Brake System; Repair Group 45; Exploded view of ESP components

Display group number 004

‒ Press keys 0, 0 and 4.
‒ Confirm entry with Q key.

→ A measured value block always has 4 display zones -arrows-. Explanatory notes on values 1 - 4 in the individual display zones are given in the following test table.

Reading measured value block 4 ⇒

⇒ 1 ⇒ 2 ⇒ 3 ⇒ 4

→ Indicated on display (with vehicle stationary):

Reading measured value block 4⇒

0.05 0.0m/s2 1.265/s

The next display group number down/up can be consecutively selected by pressing key -1- or key -3- respectively.

Press C key to enter next display group number.

If ⇒key is pressed, keys 0 and 8 then have to be pressed to return to "Reading measured value block" sequence.

All three values must be positive when negotiating a left-hand bend forwards.

All three values must be negative (-) when negotiating a right-hand bend forwards.

Reading measured value block			4 ⇒	Display group number: 004
0,0°	0.0m/s2	0.53°/s		◂ Indicated on display (example)
				Not used
			Yaw rate sender: - Specification with vehicle stationary on flat surface:± 2.5°/s - Test step 15 =>Page 01-146
		Lateral acceleration sender: - Specification with vehicle stationary on flat surface:± 0.5m/s2 - Specification on full steering lock at a speed of 20 km/h in a left-hand bend: Measured value increases constantly with positive (not displayed) sign - Specification on full steering lock at a speed of 20 km/h in a right-hand bend: Constant increase in measured value with negative (-) sign Function 04 "Basic setting", Display group number 63 =>Page 01-136
	Steering angle sender: - Specification with vehicle stationary on flat surface: ±4.5° Function 04 "Basic setting", Display group number 60 =>Page 01-134

Display group number 005

‒ Press keys 0, 0 and 5.
‒ Confirm entry with Q key.

→ A measured value block always has 4 display zones -arrows-. Explanatory notes on values 1 - 4 in the individual display zones are given in the following test table.

Reading measured value block 5 ⇒

⇒ 1 ⇒ 2 ⇒ 3 ⇒ 4

→ Indicated on display (with vehicle stationary):

Reading measured value block 5⇒

- 0.42 bar - 0.63 bar

The next display group number down/up can be consecutively selected by pressing key -1- or key -3- respectively.

If ⇒key is pressed, keys 0 and 8 then have to be pressed to return to "Reading measured value block" sequence.

Reading measured value block			5 ⇒	Display group number: 005
-0.42 bar	-0.63 bar			◂ Indicated on display (example)
				Not used
			Not used
		Brake pressure sender - Specification with brake not pressed: <7 bar - Test steps 16 and 17 =>Page 01-140
	Brake pressure sender - Specification with brake not pressed: <7 bar - Test steps 16 and 17 =>Page 01-140

Display group number 125

‒ Press keys 1, 2 and 5.
‒ Confirm entry with Q key.

→ A measured value block always has 4 display zones -arrows-. Explanatory notes on values 1 - 4 in the individual display zones are given in the following test table.

Reading measured value block 125 ⇒

⇒ 1 ⇒ 2 ⇒ 3 ⇒ 4

→ Indicated on display (with vehicle stationary):

Reading measured value block 125 ⇒

Engine 1 Steering angle 1

Press C key to enter next display group number.

If ⇒key is pressed, keys 0 and 8 then have to be pressed to return to "Reading measured value block" sequence.

Reading measured value block			125 ⇒	Display group number: 125
Engine 1	Steering angle 1	4WD 1	Gearbox 1	◂ Indicated on display (example)
				Gearbox data bus 1) - 1 ⇒Data bus link - 0 ⇒No data bus link2)
			Not used
		Steering angle data bus - 1 ⇒Data bus link - 0 ⇒No data bus link2)
	Engine data bus - 1 ⇒Data bus link - 0 ⇒No data bus link2)

1) Vehicles with automatic gearbox only

2) Interruption in data bus link or data bus wires interchanged

=> "Current Flow Diagrams, Electrical Fault-finding and Fitting Locations" binder

Running gear self-diagnosis for ESP, steering
Self diagnosis, V.A.G Inspection Service
Performing self-diagnosis
Reading measured value block

Final control diagnosis > < Checking of brake pressure solenoid valve, in brake servo -N247

Audi Workshop Service and Repair Manuals

A2

Running gear self-diagnosis for ESP, steering Self diagnosis, V.A.G Inspection Service Performing self-diagnosis Reading measured value block

Running gear self-diagnosis for ESP, steering Self diagnosis, V.A.G Inspection Service Performing self-diagnosis Reading measured value block

Running gear self-diagnosis for ESP, steering
Self diagnosis, V.A.G Inspection Service
Performing self-diagnosis
Reading measured value block

Running gear self-diagnosis for ESP, steering
Self diagnosis, V.A.G Inspection Service
Performing self-diagnosis
Reading measured value block