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Electrical check > < Encoding control unit

A4 Mk1

Running Gear Self-diagnosis for ABS, ESP
ABS/EDL/TCS Bosch 5.0
Reading measured value block

The control unit can transfer measured values to the fault reader V.A.G 1551. This test data delivers information about the condition of the system and the sensors connected. In many cases the transferred test data can be used to support the fault finding and remedy. The measured values available from the Bosch type 5.0 system are grouped in three display groups, which can be called up via display group numbers.

  • ‒ Connect fault reader V.A.G 1551 and select "Brake electronics" with address word 03 .

Notes:

  • ◆ When the printer is switched on, the contents of the display will be printed out on the fault reader log.
  • ◆ When "Read measured value block", also check wiring and connectors for loose contacts.
  • ‒ Check the control unit version => Page 01-49 and press the ⇒ key.
 
→ Indicated on display:
Rapid data transfer     HELP
Select function XX
  • ‒ Press keys 0 and 8 for "Read measured value block" function.
 
→ Indicated on display:
Rapid data transfer     Q
08 - Read measured value block
  • ‒ Confirm input with Q key.
 
→ Indicated on display:
Read measured value block     Help
Enter display group number     XXX
  • ‒ Press keys 0, 0 and 1.
  • ‒ Confirm input with Q key.

Test table, display group 1

  • ◆ The display zones 1 to 4 show the actual wheel speeds at the tyre circumference in km/h. These are calculated by control unit -J104 on the basis of the pulses received from the wheel speed sensors. If one of the display zones shows no reading, proceed as for fault codes 00283, 00285, 00287, 00290 "Speed sensor". Fault table => Page 01-95.
  • ◆ In order to check that the speed sensor signals are correctly assigned to the four wheels, the vehicle must be raised. On vehicles with manual gearbox put the gear lever in neutral. On vehicles with automatic gearbox move the selector lever to position "N". Turn appropriate wheel by hand. The other wheels must be prevented from rotating.
  • ◆ When the vehicle is accelerated uniformly on a dry surface, the displayed values will increase continuously in rising whole numbers, e.g. 6km/h, 7km/h, 8 km/h.... The difference between displayed values 1 to 4 should be no more than ±1 km/h(rounding errors).If the values jump, for instance from... 6km/h, 7km/h, to 12 km/h... or if the difference between the displayed values is greater than ±1 km/h then check the installation of the wheel speed sensors and rotors.

=> FWD and 4WD Running Gear; Repair group 40

=> FWD and 4WD Running Gear; Repair group 42

Reading measured value block

1 ⇒

◂ Indicated on display

1 ... 19 1)
km/h

1 ... 19 1)
km/h

1 ... 19 1)
km/h

1 ... 19 1)
km/h

Wheel speed, rear right

Wheel speed, rear left

Wheel speed, front right

Wheel speed, front left

1) Control unit -J104 terminates self-diagnosis if speed exceeds 19 km/h.

Display group numbers can be selected in sequence by pressing keys <-1 and 3-> on V.A.G 1551 or arrow keys ↑ and ↓ on V.A.G 1552.

  • ‒ Press key C in order to enter the display group number manually.
 
→ Indicated on display:
Reading measured value block
Enter display group number XXX
  • ‒ Press keys 0, 0 and 2.
  • ‒ Confirm input with Q key.

Test table, display group 2

Reading measured value block

2 ⇒

◂ Indicated on display

0 or 1

0 or 1

0 or 1

0 or 1

Solenoid valve relay:
On vehicles with FWD this display is shifted one zone to the left.
- 0 ⇒ Not permissible during "Read measured value block" function; relay not actuated when ignition switched on.
Perform "Electrical check" , Test step 11.
- 1 ⇒ Specified value; relay actuated by control unit -J104 when ignition is switched on.

Voltage at return pump motor:
On vehicles with FWD this display is shifted one zone to the left.
- 0 ⇒ Specified value, no voltage applied to return pump motor.
- 1 ⇒Not permissible during "Read measured value block" function; voltage applied to return pump motor.
Perform "Electrical check" , Test step 12.

Brake light switch: additional signal for 4WD models only:
- 0 ⇒ Brake pedal not operated
- 1 ⇒ Brake pedal operated



Check brake light switch in the event of deviation.
=> Current Flow Diagrams, Electrical Fault-finding and Fitting Locations

Brake light switch: Signal for FWD and 4WD:
- 0 ⇒ Brake pedal not operated
- 1 ⇒ Brake pedal operated



Check the brake light switch in the event of deviation.
=> Current Flow Diagrams, Electrical Fault-finding and Fitting Locations

Display group numbers can be selected in sequence by pressing keys <-1 and 3-> on V.A.G 1551 or arrow keys ↑ and ↓ on V.A.G 1552.

  • ‒ Press key C in order to enter the display group number manually.
 
→ Indicated on display:
Reading measured value block
Enter display group number XXX

Note for display group 3:

If display zones for engine speed and actual engine torque are to be read out with engine running communication between fault reader and control unit must be terminated with "End output" function => Page 01-14. Then start engine and set up diagnostic link between fault reader and control unit again.

  • ‒ Press keys 0 and 8 for "Read measured value block" function.
  • ‒ Confirm input with Q key.
  • ‒ Press keys 0, 0 and 3.
  • ‒ Confirm input with Q key.

Test table, display group 3

Reading measured value block

3 ⇒

◂ Indicated on display

60 ... 8000
rpm

0 ... 100
%

0 or 1

---

TCS switch: (only on vehicles with traction control system (TCS/TCS):
- 0 ⇒ TCS switch not activated.
- 1 ⇒TCS switch actuated; system status switches from "TCS OFF" to "TCS ON" or vice versa.
- The TCS warning lamp will light up if the TCS is switched off with the TCS switch.
Check TCS switch in the event of deviation. "Electrical check" => Page 01-65, Test step 22.

Actual engine torque (MMI): (only on vehicles with traction control system (TCS/TCS):
- 0% ⇒Vehicle in overrun phase.
- 20% - 30% ⇒equivalent to engine idling.
- 100% ⇒ Engine delivering maximum torque.
If no display appears, proceed as described for fault code 00647 "ABS-TCS/engine electrical connection 2": Fault table => Page 01-95.

Engine speed: (only on vehicles with traction control system (TCS/TCS):
- The display indicates engine speed in steps of 60 rpm, starting at 60 rpm.
If no display appears, proceed in line with fault 00529 "Speed information missing, no signal". Fault table => Page 01-95.

Electrical check > < Encoding control unit