Audi Workshop Service and Repair Manuals

Faults displayed by warning lamps in instrument cluster 1 -  “Brake warning” symbol 2 -  ABS warning lamp -K47- 3 -  Handbrake warning lamp -K14- 4 -  Traction control system warning lamp -K86-

“Brake warning” symbol	ABS warning lamp -K47-	Traction control system warning lamp -K86-	Explanation
On	On	On	Test sequence after switching on ignition (first two seconds).
Off	Off	Off	System OK (2 seconds after switching on ignition)
Off	Off	On	TCS/ESP failure or TCS/ESP deactivated by manual switch; ABS, EDL and EBPD remain active
Off	Off	flashes	TCS/ESP control function is operating
Off	On	On	ABS/EDL/TCS system failure (e.g. wheel speed sensor defective), the EBPD remains fully functional.
On	On	On	ABS/EDL/TCS/EBPD system failure (e.g. several wheel speed sensors defective)
On	Off	Off	Brake fluid level too low; all systems remain functional

WARNING There is a risk of accident if the ABS warning lamp -K47- and the “brake warning symbol” both light up. The function of the brake system will be impaired. As the brake pressure is no longer controlled by the electronic brake force distribution the rear wheels tend to brake excessively. Due to this the rear of the vehicle may break away unexpectedly.

The ABS warning lamp -K47--item 2- lights up during the test sequence (self-test) The system runs through an automatic test sequence when the ignition is switched on: the ABS warning lamp -K47- is activated by the ABS with EDL control unit -J104- and lights up for 2 seconds. During this period the control unit tests the following functions via self-test. t  The voltage supply is checked, at least 10.0 V. t  The control unit including the valve windings is checked. t  A speed sensor check (electrical test) is carried out; this is only completed at 20 km/h. t  Control unit code is checked. If the system does not perform the test sequence: –  Check voltage supply of ABS with EDL control unit -J104- (perform electrical check, step 3 → Anchor).

The ABS warning lamp -K47--item 2- stays on after the test sequence is completed If a fault affecting only the anti-lock brake system is detected by self-diagnosis, the ABS is switched off. The conventional brake system remains fully functional. The causes of the fault may be as follows: t  Voltage supply is below 10 Volts. t  A fault exists which affects only the ABS. t  A sensor fault has occurred after the last start (sporadic fault). In this case the ABS warning lamp goes out automatically after the vehicle is started again and the road speed exceeds 20 km/h. t  Connection between ABS with EDL control unit -J104- and instrument cluster is faulty or instrument cluster faulty (perform electrical check, step 15 → Anchor).

The ABS warning lamp -K47--item 2- goes out after the test sequence is completed, but “brake warning symbol”-1- remains on and the gong sounds three times All systems remain functional. The causes of the fault may be as follows: t  Brake fluid level too low. t  Fault in instrument cluster → Electrical system, self-diagnosis; Rep. Gr.01 or → Current flow diagrams, Electrical fault finding and Fitting locations.

A - Vehicles without navigation system: the ABS warning lamp -K47--item 2- does not go out after the test sequence is completed, and “brake warning” symbol -1- is on B - Vehicles with navigation system: the ABS warning lamp -K47--item 2- does not go out after test sequence is completed and handbrake warning lamp -K14--3- lights up when vehicle speed first exceeds 10 km/h or engine speed first exceeds 2000 rpm, and the gong sounds three times The ABS system is defective and the EBPD system deactivated.   WARNING There is a risk of accident if the ABS warning lamp -K47- and the “brake warning symbol” both light up. The function of the brake system will be impaired. As the brake pressure is no longer controlled by the electronic brake force distribution the rear wheels tend to brake excessively. Due to this the rear of the vehicle may break away unexpectedly.

The traction control system warning lamp -K86--item 4- remains on after the test sequence is completed The causes of the fault may be as follows: t  A fault in the system affecting only the TCS/ESP. ABS/EDL and EBPD remain fully functional. t  The TCS/ESP system was switched off with the traction control system switch -E132-. t  Short circuit to positive in traction control system switch -E132- t  Short circuit to earth for activation of traction control system warning lamp -K86-. t  Open circuit in wiring for activation of traction control system warning lamp -K86-.

The traction control system warning lamp -K86--item 4- lights up for 100 milliseconds after the ignition is switched on t  A coding without TCS/ESP control has been entered.

The ABS warning lamp -K47--item 2- and the “brake warning” symbol -1- flash and the traction control system warning lamp -K86- remains on after the test sequence is completed The causes of the fault may be as follows: t  The control unit is not coded (Code 00000).   Note If the ABS warning lamp -K47- and the “brake warning” symbol do not light up but the brake system is not fully functional, the fault must be traced in the conventional brake system → Brake system; Rep. Gr.46 and → Rep. Gr.47.